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The fascinating field of 3d–4f single-molecule magnets (SMMs) has gained considerable attention since the breakthrough work of slow relaxation of magnetization in a CuII–TbIII system. In this report, we present the synthesis of three new isostructural and isomorphous [CuLn(L)(NO3)3(H2O)] complexes (Ln = Gd (1), Tb (2), and Dy (3)), derived from a compartmental Schiff base ligand, H2L. To further unravel the magnetic dynamics, we also developed two closely related ZnII–DyIII complexes, [ZnDy(L)(NO3)3(py)] (4) and [ZnDy(L)(OAc)(piv)(NO3)] (5), with py, OAc, and piv representing pyridine, acetate, and pivalate ions, respectively. These complexes offer an opportunity to explore the influence of paramagnetic CuII and diamagnetic ZnII ions on dynamic magnetic behaviors. Magnetic susceptibility measurements indicate a dominant Stark sublevel depopulation effect for the DyIII ions in complexes 4 and 5, alongside pronounced ferromagnetic interactions between the CuII ion and the respective LnIII ions in 1–3, as commonly observed for ≥4f7 ions. Intriguingly, all synthesized complexes exhibit dynamic magnetic behavior in the presence of an applied magnetic field, indicating that the ferromagnetic influence of CuII ions and the charge polarization from the ZnII ion play crucial roles in shaping their magnetic properties. The most important achievement of this study is the observation of field-induced slow relaxation of magnetization in complex 1, despite the isotropic nature of the GdIII ion. Given the scarcity of CuII–GdIII systems demonstrating single-molecule magnet behavior, this work adds a remarkable contribution to the expanding field of GdIII-based SMMs, offering fresh insights and broadening the horizons of future research in this promising area. [ABSTRACT FROM AUTHOR]

The 1,1-azoliumdithiocarboxylate cAACMe-CS2 (1a) was prepared and its redox chemistry was evaluated and compared to NHC based dithiocarboxylates IDipp-CS2 (1b) and IMes-CS2 (1c). Radical anions [carbene-CS2]˙− were prepared by metallic reduction as the potassium or magnesium ion complexes [K(18-crown-6)(cAACMe-CS2)] (2a), [K(18-crown-6)(NHC-CS2)] (NHC = IDipp: 2b, IMes: 2c), and [Mg(DippNacNac)(cAACMe-CS2)] (3) and extensively characterized (SC-XRD, EPR, UV/VIS/NIR, DFT). These complexes represent the first examples of isolated radical anions of 1,1-dithiolenes. [ABSTRACT FROM AUTHOR]

Nickel is an important element utilized in various industrial/metallurgical processes, such as surgical and dental prostheses, Ni-Cd batteries, paint pigments, electroplating, ceramics, computer magnetic tapes, catalysis, and alloy manufacturing. However, its extensive use and associated waste production have led to increased nickel pollution in soils and water bodies, which adversely affects human health, animals and plants. This issue has prompted researchers to develop various optical probes, hereafter luminescent/colorimetric sensors, for the facile, sensitive and selective detection of nickel, particularly in biological and environmental contexts. In recent years, numerous functionalized chemosensors have been reported for imaging Ni2+, both in vivo and in vitro. In this context, metal-based receptors offer clear advantages over conventional organic sensors (viz., organic ligands, polymers, and membranes) in terms of cost, durability, stability, water solubility, recyclability, chemical flexibility and scope. This review highlights recent advancements in the design and fabrication of hybrid receptors (i.e., metal complexes and MOFs) for the specific detection of Ni2+ ions in complex environmental and biological mixtures. [ABSTRACT FROM AUTHOR]

This article considers the problem of the influence of the solvation shell on the ultraviolet-visible absorption spectra of π-conjugated complexes of different metal ions with dicarbonyl ligands. Based on a wide spectral dataset that has been previously collected, we report the direct correlation between the wavelength of maximum absorbance of the complexes and the coordination properties of the metal ions. Chalcogen-bearing diketones (2-furoyl-trifluoroacetone, 2-thenoyl-trifluoroacetone, 2-selenophen-trifluoroacetone, and 2-tellurophen-trifluoroacetone) demonstrate a significant redshift (17–29 nm) of the absorption bands for complexes of metal ions with various solvation shells. The spectral shift increases with an increasing number of water molecules in the hydration sphere. Detailed measurements show the red shift even for different lanthanide complexes. The discovered relationships allow us to compare at a qualitative level the structure of the solvation shell of π-conjugated dicarbonyl complexes. [ABSTRACT FROM AUTHOR]

Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications. [ABSTRACT FROM AUTHOR]

Four novel Co(II) coordination compounds 1–4 of the general formula [Co(Ln)2][Co(NCY)4]·mCH3CN (where Ln are tridentate ligands L1 = 2,6-bis(1-hexyl-1H-benzimidazol-2-yl)pyridine for 1 and 2; L2 = 2,6-bis(1-octyl-1H-benzimidazol-2-yl)pyridine for 3; L3 = 2,6-bis(1-dodecyl-1H-benzimidazol-2-yl)pyridine for 4, Y = O for 1, 3, and 4 and Y = S for 2; m = 0 for 1 and 3, m = 0.5 for 2 and m = 2 for 4) were prepared and characterised. The molecular structures of all four compounds consist of the hexacoordinate complex cation [Co(Ln)2]2+ and tetracoordinate complex anion [Co(NCY)4]2−, with distorted octahedral and tetrahedral symmetry of coordination polyhedra, respectively. The electronic structures of all compounds feature an orbitally non-degenerate ground state well-separated from the lowest excited state, which allows the analysis of the magnetic anisotropy by the spin Hamiltonian model. ZFS parameters, derived from both CASSCF-NEVPT2 calculations and magnetic data analysis, indicate that tetrahedral anions [Co(NCY)4]2− exhibit small axial parameters ‖D‖ spanning the range of 2.2 to 7.7 cm−1, while octahedral cations [Co(Ln)2]2+ display significantly larger ‖D‖ parameters in the range of 37 to 95 cm−1. For 1–3, the Fourier-transform infrared magnetic spectroscopy (FIRMS) revealed a reasonable transmission with a magnetic absorption around the expected value for the ZFS accompanied by features allowing to identify phonon frequencies and simulate spin-phonon couplings. Dynamic magnetic investigations unveiled the field-induced slow relaxation of magnetisation, with maximal relaxation times (τ) of 92(2) μs for 2 at 2 K and BDC = 0.3 T. The temperature evolution of τ was analysed using a combination of Orbach, direct and Raman relaxations (Ueff = 8(1) K (5.6 cm−1)) or Orbach, direct and spin-phonon induced relaxations (Ueff = 10.3(9) K (7.2 cm−1)). The rest of the complexes, namely 1, 3, and 4 show field-induced slow relaxation of magnetisation with τ smaller than 16 μs. [ABSTRACT FROM AUTHOR]

In this work we report the synthesis, structural characterization and magnetic properties of a family of butterfly complexes {Cr2Ln2} with Ln = Tb (4), Ho (5), Er (6), Tm (7) and Yb (8), extending the family of previously reported isostructural compounds with Gd (1), Dy (2) and Y (3). As in 1 and 2, an anti-ferromagnetic Cr(III)–Ln(III) exchange interaction is found. For oblate ions 4 and 5, SMM behavior with a purely Orbach relaxation mechanism is observed with thermal barriers of 38 cm−1 (4) and 32 cm−1 (5). Complex 4 displays hysteresis opening up to 2.4 K with loss of magnetization at zero field. The prolate complex ions 6 and 7 are field-induced SMM's with dominant Orbach, direct and QTM relaxation mechanisms. Compound 8 did not show SMM properties. [ABSTRACT FROM AUTHOR]

4-(Aminomethyl)benzoic acid (Hamb) has been found to complex the uranyl ion in its neutral, zwitterionic form in a series of mixed-ligand complexes synthesized under solvo-hydrothermal conditions with several dicarboxylate coligands. [UO2(tdc)(Hamb)]·5H2O (1), [UO2(pda)(Hamb)]·CH3CN (2), and [UO2(cam)(Hamb)]·CH3CN (3), where tdc2−, pda2− and cam2− are 2,5-thiophenedicarboxylate, 1,2-phenylenediacetate and (1R,3S)-(+)-camphorate, respectively, crystallize as simple chains in which the dicarboxylate ligand is bridging and Hamb is terminal, all carboxylates being κ2O,O′-chelating. [UO2(pht)(Hamb)]·0.5H2O (4), where pht2− is phthalate, is a ribbonlike chain in which both ligands are bridging, while the presence of the coordinated solvent N,N-dimethylacetamide (dma) prevents polymerization in [(UO2)4(O)2(pht)2(Hamb)2(dma)2]·2H2O (5), a bis(μ3-oxo)-bridged tetranuclear assembly. 1,2-Phenylenedioxydiacetate (pdda2−) gives [UO2(pdda)(Hamb)]·0.5CH3CN (6), another ribbonlike chain in which only pdda2− is bridging. Finally, [UO2(pim)(Hamb)] (7), involving the pimelate ligand (pim2−) is a double-stranded, ribbonlike chain in which two UO2(pim) linear polymers are bridged by the Hamb ligands. In all these complexes, the ammonium group of Hamb is involved in extended hydrogen bonding giving rise to weakly bonded assemblies of higher periodicity. All complexes except 5 and 6 are emissive, with photoluminescence quantum yields between 2 and 11%, and with the exception of a broad signal associated with 1, all display the usual vibronic fine structure, with peak positions clearly related to the uranium coordination numbers. [ABSTRACT FROM AUTHOR]

A systematic study of the impact on the chemical reactivity of the oxidising n-dodecane radical cation (RH˙+) with f-element complexed 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) has been undertaken utilizing time-resolved electron pulse radiolysis/transient absorption spectroscopy and high-level quantum mechanical calculations. Lanthanide ion complexed species, [Ln((HEH[EHP])2)3], exhibited vastly increased reactivity (over 10× faster) in comparison to the non-complexed ligand in n-dodecane solvent, whose rate coefficient was k = (4.66 ± 0.22) × 109 M−1 s−1. Similar reactivity enhancement was also observed for the corresponding americium ion complex, k = (5.58 ± 0.30) × 1010 M−1 s−1. The vastly increased reactivity of these f-element complexes was not due to simple increased diffusion-control of these reactions; rather, enhanced hole transfer mechanisms for the complexes were calculated to become energetically more favourable. Interestingly, the observed reactivity trend with lanthanide ion size was not linear; instead, the rate coefficients showed an initial increase (Lu to Yb) followed by a decrease (Tm to Ho), followed by another increase (Dy to La). This behaviour was excellently predicted by the calculated reaction volumes of these complexes. Complementary cobalt-60 gamma irradiations for select lanthanide complexes demonstrated that the measured kinetic differences translated to increased ligand degradation at steady-state timescales, affording ∼38% increase in ligand loss of a 1 : 1 [La((HEH[EHP])2)3] : HEH[EHP] ratio system. [ABSTRACT FROM AUTHOR]

Herein, we apply three different copper-exchanged materials (Na–[Al]SBA-15, silica, Na–MCM-22) as hosts for a direct synthesis of CuI(1,1′-bis(diphenylphosphino)ferrocene = dppf) complexes in cationic ion exchange position. Using 31P MAS NMR spectroscopy, we show that identical complexes as after ion exchange are generated if the solids are applied as reactants directly. The homogeneity of copper exchanges is evaluated by EDX spectroscopy. Both CuI and CuII result in the formation of complexes, thereby oxidizing dppf. Cu-particles were not reactive. Optimized conditions for a maximized complex formation are identified applying quantitative 31P MAS NMR spectroscopy and ICP-OES. Only accessible copper in cationic position of the solids forms the complexes. This enables a quantification of the amount of copper in mesopores vs. the total copper amount. Thus, besides a new synthesis of the complex a suitable method for quantitative elucidation of the location of copper cations is demonstrated herein. [ABSTRACT FROM AUTHOR]

trans-9,10-Dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (deadcH2), in its racemic or R,R enantiomeric forms, has been used to synthesize eight uranyl ion complexes under solvo-hydrothermal conditions. [UO2(deadc)]·1.5CH3CN (1) and [H2NMe2]2[(UO2)2(deadc)3]·2H2O (2) crystallize as monoperiodic coordination polymers in which deadc2− forms both 4- and 7-membered chelate rings. Although synthesized in the same conditions as 2, the enantiomerically pure complex [H2NMe2]4[(UO2)2(O)(R,R-deadc)2]2 (3) is a discrete tetranuclear complex containing two μ3-oxo anions. Association with the zwitterion Ni(tpyc)2, where tpyc− is 2,2′:6′,2′′-terpyridine-4′-carboxylate, gives [(UO2)2(deadc)(deadcH)(NO3)Ni(tpyc)2]·CH3CN·2H2O (4), a rake-shaped monoperiodic assembly. [UO2(deadc)(DMA)] (5), [UO2(deadc)] (6) and [PPh4]2[(UO2)2(R,R-deadc)3] (7) crystallize as diperiodic networks with the fes, sql and hcb topologies, respectively, the thick layers formed being coated on both sides by protruding, hydrophobic dibenzobarrelene groups. Finally, [(UO2)2Ag2(deadc)3(CH3CN)2]·0.5H2O (8) contains monoperiodic uranyl–deadc2− subunits which are assembled into a triperiodic framework by bridging silver(I) cations, the latter interacting with both carboxylate groups and aromatic rings. Except for 6, all these complexes are emissive with photoluminescence quantum yields of 2–26%, and most spectra display the usual vibronic fine structure of uranyl emission. [ABSTRACT FROM AUTHOR]

A configurationally-labile helical dye, 2,4,5,7-tetranitrofluorenone oximate, is used to probe complexes made of enantiopure macrocycles and mono/divalent metal ions. Induced electronic circular dichroism (ECD) and 1H NMR responses are amplified at room temperature only in the presence of K+ and Na+ ions despite larger binding efficiency with alkaline earth metal ions. [ABSTRACT FROM AUTHOR]

Salt cluster ions produced by electrospray ionization are used for mass calibration and fundamental investigations into cluster stability and charge separation processes. However, previous studies have been limited to relatively small clusters owing to the heterogeneity associated with large, multiply-charged clusters that leads to unresolved signals in conventional m/z spectra. Here, charge detection mass spectrometry is used to measure both the mass and charge distributions of positively charged clusters of KCl, CaCl2, and LaCl3 with masses between ∼1 and 10 MDa by dynamically measuring the energy per charge, m/z, charge, and mass of simultaneously trapped individual ions throughout a 1 s trapping time. The extent of remaining hydration on the clusters, determined from the change in the frequency of ion motion with time as a result of residual water loss, follows the order KCl < CaCl2 < LaCl3, and is significantly lower than that of a pure water nanodrop, consistent with tighter water binding to the more highly charged cations in these clusters. The number of ion emission events from these clusters also follows this same trend, indicating that water at the cluster surface facilitates charge loss. A new frequency-based method to determine the magnitude of the charge loss resulting from individual ion emission events clearly resolves losses of +1 and +2 ions. Achieving this individual charge state resolution for ion emission events is an important advance in obtaining information about the late stages of bare gaseous ions formation. Future experiments on more hydrated clusters are expected to lead to a better understanding of ion formation in electrospray ionization. [ABSTRACT FROM AUTHOR]

A supramolecular approach using a polyviologen-pillar[5]arene complex as segregated ion pairs was shown to be highly efficient for the conversion of CO2 with epoxides into cyclic carbonates without the need for metals or solvents. The enhanced catalytic performance was achieved by cooperative ion pair segregation and CO2 fixation. [ABSTRACT FROM AUTHOR]

A supramolecular approach using a polyviologen-pillar[5]arene complex as segregated ion pairs was shown to be highly efficient for the conversion of CO2 with epoxides into cyclic carbonates without the need for metals or solvents. The enhanced catalytic performance was achieved by cooperative ion pair segregation and CO2 fixation. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) are unique hybrid porous materials formed by combining metal ions or clusters with organic ligands. Thiol and thioether-based MOFs belong to a specific category of MOFs where one or many thiols or thioether groups are present in organic linkers. Depending on the linkers, thiol-thioether MOFs can be divided into three categories: (i) MOFs where both thiol or thioether groups are part of the carboxylic acid ligands, (ii) MOFs where only thiol or thioether groups are present in the organic linker, and (iii) MOFs where both thiol or thioether groups are part of azolate-containing linkers. MOFs containing thiol-thioether-based acid ligands are synthesized through two primary approaches; one is by utilizing thiol and thioether-based carboxylic acid ligands where the bonding pattern of ligands with metal ions plays a vital role in MOF formation (HSAB principle). MOFs synthesized by this approach can be structurally differentiated into two categories: structures without common structural motifs and structures with common structural motifs (related to UiO-66, UiO-67, UiO-68, MIL-53, NU-1100, etc.). The second approach to synthesize thiol and thioether-based MOFs is indirect methods, where thiol or thioether functionality is introduced in MOFs by techniques like post-synthetic modifications (PSM), post-synthetic exchange (PSE) and by forming composite materials. Generally, MOFs containing only thiol-thioether-based ligands are synthesized by interfacial assisted synthesis, forming two-dimensional sheet frameworks, and show significantly high conductivity. A limited study has been done on MOFs containing thiol-thioether-based azolate ligands where both nitrogen- and sulfur-containing functionality are present in the MOF frameworks. These materials exhibit intriguing properties stemming from the interplay between metal centres, organic ligands, and sulfur functionality. As a result, they offer great potential for multifaceted applications, ranging from catalysis, sensing, and conductivity, to adsorption. This perspective is organised through an introduction, schematic representations, and tabular data of the reported thiol and thioether MOFs and concluded with future directions. [ABSTRACT FROM AUTHOR]

We report three CoII-based complexes with the general formula [CoII(L)(X)2] by changing the halide/pseudo-halide ions [X = NCSe (1SeCN); Cl (2Cl) and Br (3Br)]. The obtained τ5 and CShM values confirm a distorted square pyramidal geometry around the CoII ion in all these complexes. In these three complexes, the central CoII ion is situated above the basal plane of the square pyramidal geometry. The extent of distortion from the ideal SPY-5 geometry differs upon changing the coordinating halide/pseudo-halide ion in these complexes. This essentially results in the alteration of the anisotropic parameter D and hence impacts the magnetic properties in these complexes. This phenomenon has been corroborated with the aid of theoretical investigations. All these complexes display field-induced SIM behaviour with magnetic relaxation occurring through a combination of processes depending on the applied dc magnetic field values and dilution. [ABSTRACT FROM AUTHOR]

Four uranyl ion mixed-ligand complexes involving anionic and zwitterionic carboxylate donors have been synthesized under solvo-hydrothermal conditions. [(UO2)2(pda)2(bet)2] (1), where pda2− is 1,3-phenylenediacetate and bet is betaine, crystallizes as a monoperiodic coordination polymer in which all ligands are κ2O,O′-chelated and UO2(pda)(bet)2 units are decorating groups to the UO2(pda) chain. In [bcebpH2][UO2(bcebp)(H2O)2][UO2(tcenm)]4·2H2O (2), where tcenm3− is tris(2-carboxylatoethyl)nitromethane and bcebp is 4,4′-bis(2-carboxylatoethyl)-4,4′-bipyridinium, the two ligands are separated into different polymeric units, di- (hcb) and monoperiodic, respectively, and hydrogen bonding of the bcebpH22+ counterions to chains results in heteropolycatenation, with the counterions crossing four hexagonal networks. [(UO2)2(pht)2(bcpmb)] (3), where pht2− is phthalate and bcpmb is 1,4-bis(4′-carbonylatopyridiniomethyl)benzene, is a diperiodic network with V2O5 topology, while [(UO2)4(O)2(kpim)2(bcpmb)] (4), where kpim2− is 4-ketopimelate, is a diperiodic network with bis(μ3-oxo)-bridged U4O2 secondary building units as nodes and sql topology. In this last case, the large size of the rings allows for 2D + 2D → 3D inclined polycatenation to occur. The relative strength of anionic and zwitterionic carboxylate donors and the importance of weak interactions in the structures are discussed. [ABSTRACT FROM AUTHOR]

Three MnII complexes, named Mn2(HATNA)2(CH3OH)4 (1), {[Mn3(ATNA)2(DMF)2(H2O)2]·0.5DMF·0.5H2O}n (2, DMF = N,N-dimethylformamide), and {[Mn6(ATNA)4(H2O)10]·8DMSO·2.5H2O}n (3, DMSO = dimethyl sulphoxide), were successfully synthesized by the reaction of the ligand azotetrazole-3-hydroxy-2-naphthoic acid (H3ATNA) and Mn(CH3COO)2 in CH3OH, DMF, and DMSO, respectively. A binuclear structure was found for complex 1, with the two Mn(II) ions doubly bridged through N–N linkers from the two tetrazole rings. Both 2 and 3 displayed one-dimensional structures. Magnetic studies show that antiferromagnetic interactions of Mn(II) ions existed in complexes 1–3. All the complexes exhibited luminescence emission peaks at room temperature. [ABSTRACT FROM AUTHOR]

Four Co(II) complexes [CoII2(H2L1)Cl2]·2MeCN (1), [CoII2(H2L2)Cl2] (2), [CoII2(H2L1)(acac)2]·2MeCN (3), and [CoII2(H2L2)(acac)2]2 (4) (acac = acetylacetone, H2L1 = N,N′-bis[(2-hydroxybenzylideneamino)propyl]piperazine, H2L2 = N,N′-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl)piperazine) based on symmetric Schiff base ligands were synthesized and charactered. They are all symmetric Co(II) dimers, in which Co(II) ions in complexes 1 and 2 are four-coordinate tetrahedral, and Co(II) ions in complexes 3 and 4 are five-coordinate trigonal bipyramidal. The coordination geometries of the Co(II) ions change from tetrahedral to trigonal bipyramidal by regulating the coordination anions. Furthermore, remote substituents of the aromatic benzene rings in the ligands were fine-tuned. Magnetic studies indicate that remote substituents of the ligands, as well as the coordination geometries, have no significant effect on the magnetic properties of these four Co(II) dimer complexes. [ABSTRACT FROM AUTHOR]

The two triple-armed species tris(2-carboxyethyl)nitromethane (H3tcenm) and tris(2-carboxyethyl)phosphine (H3tcep) have been used to synthesize seven uranyl ion complexes under (solvo)-hydrothermal conditions and in the presence of various structure-directing cations. The three carboxylate groups chelate three different cations and the nitro group is uncoordinated in [H2NMe2][UO2(tcenm)]·3H2O (1), [C(NH2)3][UO2(tcenm)]·0.5H2O (2) and [PPh3Me][UO2(tcenm)] (3), which crystallize as diperiodic coordination polymers with the hcb topology and minor variations in shape depending on the counterion. The two isomorphous complexes [UO2(tcenm)M(bipy)2][UO2(tcenm)]·3H2O, with M = Ni (4) or Cu (5) and bipy = 2,2′-bipyridine, display the same arrangement, with a M(bipy)22+ group bridging two adjoining carboxylate donors in one uranyl equatorial plane. [(UO2)2(tcenm)2Cu(R,S-Me6cyclam)]·2H2O (6), where R,S-Me6cyclam = 7(R),14(S)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, is the only triperiodic framework in the series, with the tcs topology resulting from CuII pillaring diperiodic, uranyl-based sql networks. H3tcep is oxidized in situ to give the phosphine oxide H3tcepo, which is partially deprotonated in [UO2(Htcepo)] (7); the phosphine oxide and the two carboxylate groups are coordinated, and the diperiodic, three-dimensional network formed has the point symbol {66} and the vertex symbol 62·62·63·66·64·64, with the rings involved in Hopf links formation. Only complexes 3 and 7 are significantly emissive in the solid state, with photoluminescence quantum yields of 9%, and the emission maxima positions are in agreement with the number of uranyl equatorial donors. [ABSTRACT FROM AUTHOR]

We report a joint experimental and theoretical study of RuO2/TiO2 heterostructures. In the experimental section, mesoporous RuO2/TiO2 heterostructures were prepared by impregnation of mesoporous TiO2 nanoparticles which were synthesized from a new precursor, Na2[Ti(C2O4)3], in an aqueous solution of ruthenium(III) chloride followed by calcination at 300 °C. Using various techniques, the prepared TiO2 and RuO2/TiO2 heterostructures were extensively characterized. The photoelectocatalytic application of the as-prepared heterostructures was then investigated toward the hydrogen evolution reaction (HER). The results illustrated that RuO2 is dispersed uniformly on the TiO2 surface. The loading of RuO2 on TiO2 decreases the band gap energy and extends the absorption edge to the visible light region. This wide absorption extends the photoelectrocatalytic activity of RuO2/TiO2 heterostructures. To obtain a deeper understanding of the increase of the photoelectrocatalytic activity of RuO2/TiO2 heterostructures compared to pure TiO2, theoretical calculations at the density functional theory (DFT) level were performed on some model clusters of pure TiO2 and the RuO2/TiO2 heterostructure. The theoretical results elucidated that the recombination ratio of electron–hole pairs decreases effectively for RuO2/TiO2 compared to pure TiO2. [ABSTRACT FROM AUTHOR]

An electrochemical chiral sensing platform based on a multi-substituted ferrocene–cuprous ion (Cu+) complex is constructed for the discrimination of electroactive amino acid (AA) isomers. Due to the opposite configurations of the AA isomers, the developed multi-substituted ferrocene–Cu+ can preferably combine with a right-handed AA (D -AA) isomer to form the ternary complex of multi-substituted ferrocene–Cu+- D -AA through π–π interactions, resulting in higher peak currents of D -AA. Therefore, the isomers of electroactive AA can be successfully discriminated. Among the tested electroactive AA isomers, the chiral sensing platform exhibits higher discrimination capability toward the isomers of tryptophan (Trp) than that of tyrosine (Tyr) and cysteine (Cys), which might be ascribed to the stronger π–π interactions between the benzene ring of the multi-substituted ferrocene and the indole ring of the Trp isomers. [ABSTRACT FROM AUTHOR]

The subcomponent self-assembly of 4,6-dihydrazinopyrimidine and o-vanillin/salicylaldehyde with different DyIII salts leads to the formation of Dy2 (1–3) and grid-like Dy4 (4) compounds with formulas of [Dy2L(DMF)4(NO3)4]·2DMF (1), [Dy2L2(CH3COO)4(CH3OH)2]·10H2O (2), [Dy2L′2(CH3COO)4(CH3OH)2]·2H2O·2CH3OH (3) and [Dy4Na2L2(μ2-OH)2(PhCOO)8(CH3OH)(H2O)]·CH3CN·2CH3OH·7H2O (4). In all cases, the DyIII ions are nine coordinate but the different features of coordinated solvent molecules and anions result in diverse coordination geometries in their respective structures. Notably, by introducing various axial coordinating anions with different electronegativities (NO3−, CH3COO− and C6H5COO−), the effective energy barriers were progressively enhanced (52–207 K) in this system. Detailed magnetic studies for these complexes revealed obvious magnetic interactions in complex 1 and clear single molecule magnet (SMM) behavior with anisotropy barriers of 52, 56 and 58.4 K for 1–3, respectively. Moreover, we find that the incorporation of benzoates into the axial position of the DyIII ions in complex 4 leads to the occurrence of two clear distinct relaxation processes, with energy barriers of 94.9 and 207.2 K, respectively. This result presents an example of the effects of axial coordinating anions on the SMM behavior, providing a valid route towards enhancing the slow magnetic relaxation of 4f based SMMs via incorporating diverse coordination anions into the subcomponent self-assembly system. [ABSTRACT FROM AUTHOR]

Three complexes of formulae [Fe2(L)2Cl4] (1), [Co2(L)2Cl4] (2) and [Ni(L)2Cl2]·CH2Cl2 (3) were synthesized from the reactions of the L ligand (L = 1-chloro-3-(pyridin-2-yl)imidazo[1,5-a]pyridine) with chloride salts of FeII, CoII, and NiII ions under solvothermal conditions. The structures of 1–3 were determined by single-crystal X-ray diffraction analysis. The binuclear complexes 1 and 2 are isostructural. The two metal ions of each complex show different coordination environments. Complex 3 displays a mononuclear structure. The magnetic properties of 1–3 were studied. Complex 1 exhibits a slow magnetization relaxation behaviour. The catalytic properties of complexes 1–3 toward the OER under basic conditions were studied. They were all catalytically active, and complex 3 showed a higher activity. [ABSTRACT FROM AUTHOR]

As a part of our ongoing research, we have synthesized a new fluorescence probe, p-C4A, based on a calix[4]arene substituted with 4-aminoquinoline moieties with amide linkages. p-C4A can selectively recognize Li+ and PO43− ions and has been characterized via an emission study, an absorption study, ESI-MS spectroscopy, a 1H NMR study and cyclic voltammetry. The fluorescence sensor p-C4A can operate over a concentration range of 5–170 nM for Li+ sensing and 5–80 nM for PO43− sensing. The R2 values obtained for the sensing of Li+ and PO43− ions are 0.9962 and 0.9911, respectively. p-C4A demonstrates a minimum detection limit of 6.15 nM for Li+ and 9.0 nM for PO43−. The quantum yields of p-C4A as its Li+ and PO43− ion complexes were found to be 0.014 and 0.27, respectively. Herein, we report an easy-to-use, low-cost, disposable, paper-based, fluorescent, wax-printed device for the rapid chemical screening of Li+ and PO43−. This device can be used as a quick, portable, multiple-test panel that is simple, lightweight, and disposable. Moreover, in order to assess its analytical applicability, the prepared sensor was successfully used for the determination of Li+ and PO43− from wastewater samples, validating the proposed ion recovery method with 96–99% recovery rates. [ABSTRACT FROM AUTHOR]

Although progress has been made in the design and synthesis of chiral lanthanide clusters with pleasing structural connections and special shapes, assembly rules that guide their directional construction are still lacking. We reacted R/S -mandelic acid hydrazide, 2,3-dihydroxybenzaldehyde and DyCl3·6H2O under solvothermal conditions to obtain two octanuclear chirality clusters R-1 and S-1 , which are the enantiomers of each other. R/S -mandelic acid hydrazide and 2,3-dihydroxybenzaldehyde underwent an in situ reaction under "one-pot" conditions to generate a monohydrazone-type organic ligand R/S -mandelic acid hydrazide-2,3-dihydroxybenzaldehyde hydrazone (R/S -H2L). Four R/S -H2L ligands captured eight metal-centered Dy(III) ions and presented an annular arrangement, which assembled to form a pinwheel-shaped chiral cluster R/S-1. The benzene rings at the four vertices of R/S-1 can rotate freely as rotors. This is the first discovery of an annular growth mechanism during the self-assembly of lanthanide clusters. By changing the metal salt to Dy(NO3)3·6H2O, two twist-shaped hexanuclear clusters R-2 and S-2 , which are the enantiomers of each other were obtained. Four R/S -H2L and two R/S -H3L ligands captured six metal-centered Dy(III) ions, respectively, and were assembled through a linear growth mechanism to form the twist-shaped chiral clusters R/S-2. This is the first time that a linear growth mechanism has been proposed for the directional construction of lanthanide clusters with specific shapes. Circular dichroism results showed that R/S-1 and R/S-2 were both chiral clusters and enantiomers of each other. Magnetic studies showed that both R/S-1 and R/S-2 exhibit obvious single-molecule magnet (SMM) behaviors under zero-field conditions. This work is the first to propose an annular/linear growth mechanism for the design and synthesis of lanthanide clusters and allows the directional construction of chiral lanthanide clusters with special shapes and structural connections. [ABSTRACT FROM AUTHOR]

Phase transition materials that can exist in two energetically stable states are suitable for a range of applications in electronics and physics. In this work, we report a new organic–inorganic hybrid compound, [(CH3)3NH]4[Fe(SCN)6]Cl, which undergoes a structural phase transition at about 195 K accompanied with the thermal hysteresis of dielectric bistability as well as anisotropic dielectric relaxation along the crystallographic a-, b-, and c-axis in a broad temperature range, which may be considered as a potential relaxor-type dielectric material. The analyses of the dynamic structures revealed that the structural phase transition was induced by the synergetic effect of orientation of the (CH3)3NH+ cations, displacement of the Cl− anions, and slight tilling of the [Fe(SCN)6]3− complex ions. Among these, the slowly progressive reorientation of the (CH3)3NH+ cations are mainly responsible for the prominent dielectric relaxation behavior. Further studies on dielectric relaxation disclose a rather narrow distribution of the relaxation time and practically a mono-dispersive type dielectric relaxation process, which may be considered as a Debye model. [ABSTRACT FROM AUTHOR]

Due to the heterometallic synergistic effects from different metals, heterometallic clusters are of great importance in small-molecule activation and catalysis. For example, both biological nitrogen fixation and photosynthetic splitting of water into oxygen are thought to involve multimetallic catalytic sites with d-block transition metals. Benefitting from the larger coordination numbers of f-block metals (rare-earth metals and actinide elements), heterometallic clusters containing f-block metal–metal bonds have long attracted the interest of both experimental and theoretical chemists. Therefore, a series of effective strategies or platforms have been developed in recent years for the construction of heterometallic clusters with f-block metal–metal bonds. More importantly, synergistic effects between f-block metals and transition metals have been observed in small-molecule activation and catalysis. This tutorial review highlights the recent advances in the construction of heterometallic molecular clusters with f-block metal–metal bonds and also their reactivities and applications. It is hoped that this tutorial review will persuade chemists to develop more efficient strategies to construct clusters with f-block metal–metal bonds and also further expand their applications with heterometallic synergistic effects. [ABSTRACT FROM AUTHOR]

In this work, we report two supramolecular isomorphic dodecanuclear cobalt complexes, [Co12(mtz)3(L)6(NO3)2(OH)(N3)3]·(OH)3 (1) and [Co12(mtz)3(L)6(NO3)2(OH)(N3)(OAc)]·(OH)4 (2), (Hmtz = 5-methyl-1H-tetrazole, H2L = 7,7′-(ethane-1,1-diyl) diquinolin-8-ol) crystallizing in the P¯ space group with the same unit cell parameters. In 1 and 2, two pirate hat-like hexanuclear Co6(NO3)(L)3 units form the same dodecanuclear metal shell, but the ligands between the hexanuclear units as the core are distinct. The introduction of acetate anions leads to a blue shift of the absorption band in the visible region. Magnetism studies indicate an antiferromagnetic interaction between the CoII ions in the clusters. [ABSTRACT FROM AUTHOR]

The cellulose solution state and formation mechanism are fundamental and essential issues in cellulose science and related industry. Herein, we revealed the cellulose solution state and formation mechanism in a series of ionic liquids (ILs) and IL/co-solvent systems. The types and amounts of ILs and co-solvents have a significant influence on the initial solution state and the dissolution process of cellulose. Acetate-based ILs and a high co-solvent content are beneficial to the formation of a molecularly dispersed state. In contrast, chloride-based ILs or a low content of co-solvents make cellulose adopt a coexistence state of single molecular chains and undissolved cellulose microdomains, which gradually convert into a molecularly dispersed state. The hydrogen-bonding basicity and microstructure of ILs and co-solvents are the determining factors for the initial solution state and dissolution process of cellulose. In IL/co-solvent systems with a high hydrogen-bonding basicity (>0.92) and a small ion cluster structure, a molecularly dispersed solution of cellulose forms directly. Such a clear and comprehensive outline of the solution state, dissolution process and regulation principles is of critical significance to understand cellulose dissolution, characterize the physical properties of cellulose, control homogeneous derivatization, and process cellulose materials. [ABSTRACT FROM AUTHOR]

To enhance light absorption in the visible region for the utilization of sunlight, eight mixed-valence polynuclear CuI/CuII clusters have been synthesized for evaluating their photothermal conversion performance. They are fabricated considering the ligand's electron density distribution inhomogeneity using 1,2,3-triazole (3N) or tetrazole (4N) and different mono-phosphine ligands. We report here the synthesis, crystal structure, characterization, optical properties, and photothermal conversion performance of these clusters. X-ray crystal structures reveal that those pentanuclear clusters are neutral clusters with octahedrally- coordinated copper(II) ion being surrounded by four tetrahedrally coordinated copper(I) ions. Interestingly, with the introduction of the mixed-valence centers, these compounds show additional light absorption centers in 350-600 nm via the IVCT transition mechanism, compared with our previously reported Cu(II) compounds. These clusters show excellent photothermal conversion performance, with an average equilibrium temperature (~60 °C) and a temperature increment (~40 °C), which are also superior to Cu(II) complexes (the average equilibrium temperature ~55 °C). This work proves that it is possible to design and prepare new polynuclear mixed-valence CuI/CuII clusters for achieving high-performance photothermal conversion materials. [ABSTRACT FROM AUTHOR]

We report the peculiar characteristics of a polydentate Schiff base towards zinc(II) ions in the presence of pseudohalides (thiocyanate and azide) and the charge transport properties of zinc complex mediated devices in the solid state. The designed polydentate chelator, [HL = (Z)-2-methoxy-6-(((2-methoxy phenyl)imino)methyl)phenol)], was synthesized by coupling of o-anisidine and o-vanillin in ethanol under reflux, and the ligand was isolated in a single-crystalline phase in an orthorhombic system with the Pbca space group. Interestingly, the ligand bears unique structural features towards the coordination with zinc ions in the presence of thiocyanate and azide ions leading to mononuclear and dinuclear zinc–Schiff base–pseudohalide complexes (ZnP11NCS and ZnP11N3), respectively. In the ZnP11NCS complex, the Schiff base ligand becomes protonated to a zwitterionic form, which causes their monodentate/bidentate behaviour towards Zn(II) ions. In contrast, the ligand, P11, under identical reaction conditions, behaves as a tridentate chelating ligand towards Zn(II) ions in the ZnP11N3 complex having a symmetric μ1,1-phenoxo-bridge. In both complexes, NCS and N3 ions coordinate with Zn(II) ions in a terminal coordination mode. Crystal engineering approaches and Hirshfeld surface and energy framework analysis of the complexes delineate the dominant contribution of H⋯S and H⋯N hydrogen bonding and C–H⋯π interactions for a structural assortment of the compounds. Further, the complexes have been employed to construct devices to explore the charge transport properties in the dark and a shower of photons. The ZnP11N3 complex exhibits better charge transport properties than ZnP11NCS as evident from high DC conductivity measurement values and relaxation times caused by optical phonon activation under dark and light conditions. This feature might be utilized to explore their template applications in designing electronic devices as per the industry's needs. [ABSTRACT FROM AUTHOR]

Three ½ mass oriented rare earth element (REE) M2+ correction approaches (fixed factor, a dual internal standard, and an in-sample) are evaluated for use in an ICP-MS environmental method update. The multi-variant-based evaluation includes analyzing the same 19 REE-fortified matrices on eight different days over a two-month period using two instrument tunes. These REE-fortified matrices were also analyzed using HR-ICP-MS and ICP-MS/MS to estimate the reference value for use in the principal component analysis (PCA) and hierarchical modeling evaluation. A fixed factor is unable to compensate for matrix and mass dependent drift and because of this it generates the largest across matrix, tune, and day 95th percent confidence bounds for the REE corrections on both As (1.1 ppb) and Se (23 ppb) using samples fortified with 100 ppb Nd, Sm & Gd. The PCA analysis indicated that M2+ ions cluster together across matrix, tune and day better than M1+ and these tighter correlations are reflected in reduced 95th percentile confidence bounds for dual M2+ internal standards (M2+; As = 0.3 ppb; Se = 5.4 ppb; n = 704) relative to M1+ internal standards (M1+; As = 0.6 ppb; Se = 12.0 ppb; n = 1056). The use of an in-sample M2+ correction produced comparable 95th percent confidence bounds (As = 0.2 ppb; Se = 3.4 ppb; n = 352) relative to the M2+ internal standard approaches. Finally, the hierarchical modeling indicated M2+ ions as internal standards tend to minimize the across day variability induced by cone changes and the daily reoccurring matrix shifts in the M2+/M1+ ratio associated with 250 ppm matrices of Na, Ca, and Mg. This internal standard driven reduction in variability can be beneficial in compliance monitoring methods. [ABSTRACT FROM AUTHOR]

This study presents a molecular surface modification approach to synthesizing a family of silver chalcogenolate clusters (SCCs) containing the same [Ag12S6] core and different surface-bonded organic ligands (DMAc or pyridines; DMAc = dimethylacetamide), with the aim of tuning the luminescence properties and increasing the structural stability of the SCCs. The SCCs displayed strong and tuneable luminescence emissions at 77 K (from green to orange to red) as influenced by the peripheral pyridine ligands. In addition, SCC 5 protected by pyridine molecules was stable in ambient air, humid air and even liquid water for a long time (up to 1 week), and it was more structurally stable than SCC 1 bonded with DMAc molecules under the same conditions. The high structural stability of SCC 5 can be explained by the ability of pyridine molecules to form strong coordination bonds with silver atoms. This study offers a new way of designing structurally stable metal nanoclusters with tuneable physicochemical properties. [ABSTRACT FROM AUTHOR]

Some of the uncertainties inherent to solvo-hydrothermal synthetic methods which often hinder isolation of the desired product are discussed and illustrated by the structural characterisation of four uranyl ion complexes with long-chain saturated or unsaturated aliphatic dicarboxylate ligands, this being placed in the context of previous results. [Zn(phen)2(HCOO)][UO2(muc)(HCOO)] (1), where H2muc is trans,trans-muconic (trans,trans-1,6-hexa-2,4-dienedioic) acid, includes formate anions, generated in situ from N,N-dimethylformamide (DMF) hydrolysis, as chelating ligands on both metal centres, which limits polymer periodicity. [UO2(muc)(NMP)] (2) was obtained in the presence of PPh4+ cations, but coordination of N-methyl-2-pyrrolidone (NMP) results in formation of a neutral monoperiodic polymer instead of an anionic one. Similarly, NMP complexation prevents inclusion of [Co(en)3]3+ cations in [UO2(C8)(NMP)] (3), where H2C8 is 1,8-octanedioic acid, another monoperiodic coordination polymer. No solvent is coordinated in [H2NMe2]2[(UO2)2(C13)3] (4), where H2C13 is 1,13-tridecanedioic acid, but the desired [Co(en)3]3+ counterions are displaced by H2NMe22+ cations generated in situ from DMF hydrolysis, giving a diperiodic network with the KIa topological type, isomorphous to that formed from 1,15-pentadecanedioic acid. Complexes 1 and 2 are non-emissive in the solid state, while 4 displays a broad uranyl emission peak with unresolved fine structure. [ABSTRACT FROM AUTHOR]

Bimetallic cluster ion pairs containing a quaternary phosphonium and an ultrasmall Cu2Ag3 anionic cluster protected by thiolates: (PPh3R′′)[Cu2Ag3(SR′)6] (R′SH = cyclohexylthiol (CySH), R′′ = Ph, 1; Me, 2; Et, 3; Pr, 4; R′SH = tert-butylthiol (tBuSH) and R′′ = Ph, 5) were reported. Without any chiral source, 1 crystallizes as conglomerate crystals with homochiral packings and spontaneous resolution occurs, while four other clusters 2–5 crystallize as racemic crystals with heterochiral packings. These results indicate that racemic and homochiral crystallization in the cluster system could be controlled through fine-tuning internal achiral structural components. [ABSTRACT FROM AUTHOR]

Endohedral Zintl clusters—multi-metallic anionic molecules in which a d-block or f-block metal atom is enclosed by p-block (semi)metal atoms—are very topical in contemporary inorganic chemistry. Not only do they provide insight into the embryonic states of intermetallic compounds and show promise in catalytic applications, they also shed light on the nature of chemical bonding between metal atoms. Over the past two decades, a plethora of endohedral Zintl clusters have been synthesized, revealing a fascinating diversity of molecular architectures. Many different perspectives on the bonding in them have emerged in the literature, sometimes complementary and sometimes conflicting, and there has been no concerted effort to classify the entire family based on a small number of unifying principles. A closer look, however, reveals distinct patterns in structure and bonding that reflect the extent to which valence electrons are shared between the endohedral atom and the cluster shell. We show that there is a much more uniform relationship between the total valence electron count and the structure and bonding patterns of these clusters than previously anticipated. All of the p-block (semi)metal shells can be placed on a ladder of total valence electron count that ranges between 4n +2 (closo deltahedra), 5n (closed, three-bonded polyhedra) and 6n (crown-like structures). Although some structural isomerism can occur for a given electron count, the presence of a central metal cation imposes a preference for rather regular and approximately spherical structures which maximise electrostatic interactions between the metal and the shell. In cases where the endohedral metal has relatively accessible valence electrons (from the d or f shells), it can also contribute its valence electrons to the total electron count of the cluster shell, raising the effective electron count and often altering the structural preferences. The electronic situation in any given cluster is considered from different perspectives, some more physical and some more chemical, in a way that highlights the important point that, in the end, they explain the same situation. This article provides a unifying perspective of bonding that captures the structural diversity across this diverse family of multimetallic clusters. [ABSTRACT FROM AUTHOR]

Complexation and structural investigations of the solid complex of UO22+ ions and N,N,N′,N′-tetramethyl diglycolamide isolated from a room temperature ionic liquid, for the first time, revealed that the nature and the structural features of the complex are identical to those of the complex isolated from an aqueous medium. [ABSTRACT FROM AUTHOR]

A facile bottom-up method for the synthesis of lithium titanate nanoplates using a peroxo titanium complex ion precursor is reported. Instead of employing complicated treatment with high alkali concentration, the self-organization reaction between lithium and titanium ions in the prepared ion precursor can enable the formation of layered lithium titanate crystals (Li2−xHxTi2O5, where x = 0.1 and 1.52 for as-synthesise and acid-treated samples, respectively) under low alkaline conditions. We demonstrate that layered lithium titanate crystals can be grown anisotropically into individual nanoplates. Our work presents an easy and useful platform for the production of titanate materials with various morphologies based on the interaction with ionic species. [ABSTRACT FROM AUTHOR]

We describe the implementation of a simple three-electrode surface-induced dissociation (SID) cell on a cyclic ion mobility spectrometer (cIMS) and demonstrate the utility of multipass mobility separations for resolving multiple conformations of protein complexes generated during collision-induced and surface-induced unfolding (CIU & SIU) experiments. In addition to CIU and SIU, SID of protein complexes is readily accomplished within the native instrument software and with no additional external power supplies by entering a single SID collision energy, a simplification in user experience compared to prior implementations. A set of cyclic homomeric protein complexes and a heterohexamer with known CID and SID behavior were analyzed to investigate mass and mobility resolution improvements, the latter of which improved by 20–50% (median: 33%) compared to a linear travelling wave device. Multiple passes of intact complexes, or their SID fragments, increased the mobility resolution by an average of 15% per pass, with the racetrack effect being observed after ∼3 or 4 passes, depending on the drift time spread of the analytes. Even with modest improvements to apparent mobility resolving power, multipass experiments were particularly useful for separating conformations produced from CIU and SIU experiments. We illustrate several examples where either (1) multipass experiments revealed multiple overlapping conformations previously unobserved or obscured due to limited mobility resolution, or (2) CIU or SIU conformations that appeared 'native' in a single pass experiment were actually slightly compacted or expanded, with the change only being measurable through multipass experiments. The work conducted here, the first utilization of multipass cyclic ion mobility for CIU, SIU, and SID of protein assemblies and a demonstration of a wholly integrated SIU/SID workflow, paves the way for widespread adoption of SID technology for native mass spectrometry and also improves our understanding of gas-phase protein complex CIU and SIU conformationomes. [ABSTRACT FROM AUTHOR]

The synthesis, solution studies, photochemical properties and the X-ray structure of a chromone based fluorescent PdII complex are reported. The ligand contains two chromone units linked as side arms to an ethylenediamine moiety; in the PdII complex the metal ion preorganizes the two hydroxychromone units forming a rigid structure with a negatively charged pocket formed by four oxygen atoms that is able to interact with hard metal cations, such as ions, giving rise to stable bimetallic complexes. Upon interaction with LaIII and GdIII, in particular, the emission intensity at 423 nm increases by a factor of 2 and 8, respectively, while the other rare earth ions quench the fluorescence. Spectrofluorimetric studies on real matrices showed the possibility to use this system as a selective fluorescence probe to detect and trace the presence of Gadolinium in environmental water acting as an OFF–ON chemosensor, with a LOD of 0.4 ppm and a LOQ of 1.2 ppm. [ABSTRACT FROM AUTHOR]

2,2′:6′,2′′-Terpyridine-4′-carboxylic acid (tpycH) has been used as a ligand in the synthesis of four uranyl ion complexes under solvo-hydrothermal conditions. The homometallic complex [(UO2)2(tpyc)(HCOO)(OH)2] (1) contains additional hydroxide and formate anions generated in situ and it crystallizes as a monoperiodic coordination polymer in which uranyl cations are bound to both the carboxylate group and the terpyridine N3 site. Addition of PbII gives the heterometallic complex [UO2Pb(tpyc)(HCOO)2(OH)(H2O)2] (2), in which uranyl is bound to the carboxylate group while lead(II) occupies the N3 site, further hydroxide- and formate-bridging resulting in a diperiodic arrangement. Both complexes [UO2Ni(tpyc)2(OH)(H2O)]·NO3·1.5H2O (3) and [(UO2)2Ni2(tpyc)4(O)(H2O)4]·(NO3)2·6H2O (4) contain the neutral, octahedral Ni(tpyc)2 "expanded ligand" unit, the uranyl cations being bound to the divergent carboxylate groups and to bridging hydroxo or oxo groups. Complex 3 crystallizes as a heavily corrugated diperiodic assembly in which hydroxo-bridged dinuclear secondary building units are the nodes of a network of sql topology. Chiral, diperiodic polymers with the same topology but a different shape and which are involved in twofold parallel interpenetration, are formed in 4. [ABSTRACT FROM AUTHOR]

A photoelectrochemical (PEC)–electrochemical (EC) dual-mode biosensing strategy based on COF@MOF heterostructure was developed for efficiently analyzing Cr(III) ions. A two-dimensional phthalocyanine-based COF (CoPc-PT-COF) was in situ grown on a Cu-based MOF (Cu-MOF) substrate via covalent binding between carboxyl groups in Cu-MOF and amino groups in CoPc-PT-COF (denoted as CoPc-PT-COF@Cu-MOF). The coexistence of both phthalocyanine and bipyridine in CoPc-PT-COF@Cu-MOF affords the outperformed electro- and photo-activities, thus serving as a photoelectric beacon with favorable energy-band configuration and amplified electrochemical response. Due to the high porosity and rich functionality of the obtained heterostructure, the DNA strands can be tightly anchored over CoPc-PT-COF@Cu-MOF via diverse interactions. Thanks to the specific recognition between DNA strands and Cr3+ ions, the CoPc-PT-COF@Cu-MOF-based biosensor can be used to determine Cr3+ ions in an aqueous environment by PEC–EC mode. The gained biosensor shows an extremely low limit of detection (LOD) of 14.5 fM (for PEC) and 22.9 fM (for EC) within the Cr3+ concentration range from 0.1 pM to 100 nM, along with high selectivity, good reproducibility and stability. Moreover, this novel biosensor exhibits acceptable applicability for analyzing the trace Cr3+ from diverse samples (e.g., river and tap water). As a result, this work provides new insights into the construction of a high-efficiency PEC–EC dual-mode biosensor for detecting heavy metal ions from complex environments. [ABSTRACT FROM AUTHOR]

In a structural chemistry context, the dense packing and the structure-directing agent (SDA) often play a crucial role in the formation of the desired crystal structure. Herein, we present two isomorphous decavanadate-type polyoxometalates, M2(NH4)4−x[V10−xMoxO28]·10H2O (M = Li and x = 0.13 for 1; M = Na and x = 0.95 for 2), prepared by solution evaporation under ambient conditions and characterized by the techniques of EDS, ICP-MS, TG, XPS, X-band EPR spectroscopy, and X-ray single crystal and powder diffractions. Both 1 and 2 crystallized in the space group P1¯ with analogous cell parameters, containing thermodynamically stable [M2(H2O)10]2+ (M = Li or Na) clusters, NH4+ ions and decavanadate-type polyoxoanions with V5+ and Mo6+ ions. The polyoxoanions and {M2(H2O)10}2+ cluster cations, owing to their comparable dimensions, arrange alternately to form dense packing along the a + c, c- and a-axis directions. As earlier reported, however, [(H2O)0.3@K6(H2O)12]H4.45[PV7.45Mo4.55O40]·11H2O (3) crystallizes in a CsCl-type dense packing structure under analogous crystal growth conditions. In 3, the thermodynamically-stable (H2O)0.3@K6(H2O)12 cluster cation and Keggin-type {Mo4.55V7.45PO40}10.45− polyoxoanion have comparable dimensions. This study clearly reveals the structure-directing effect of thermodynamically-stable aqueous alkali metal ion clusters, initially formed in the reaction mixture, on a polyoxoanion configuration in vanadium–molybdenum polyoxometalate solid solutions. [ABSTRACT FROM AUTHOR]

Herein, we designed a diversified sensing platform for D-penicillamine based on amino-functionalized Zrbased metal--organic frameworks (UiO-66-NH2 MOFs) and 3-aminophenylboronic acid (APBA)@Alizarin Red (ARS). The boronic acid group of 3-aminophenylboronic acid could react with Alizarin Red to form an APBA@ARS complex with a yellow fluorescence emission at 580 nm and ultraviolet absorption at 435 nm. APBA@ARS can greatly quench the fluorescence of UiO-66-NH2 MOFs at 450 nm via fluorescence resonance energy transfer (FRET). When copper ions were present in the reaction system of APBA and Alizarin Red, the copper ions could complex with Alizarin Red to prevent the generation of APBA@ARS, and the absorption of Cu@ARS at 530 nm occurred. Thus, the absorbance of APBA@ARS at 435 nm declined, restoring the fluorescence of UiO-66-NH2 MOFs. Nevertheless, when D-penicillamine and copper ions coexist in the APBA and Alizarin Red reaction system, the copper ions would complex with the sulfhydryl group of D-penicillamine and no longer hinder the generation of APBA@ARS, and the fluorescence of UiO-66-NH2 MOFs is quenched again. Meanwhile, the absorbance of APBA@ARS at 435 nm enhanced and the absorbance at 530 nm decreased. Thus, a fluorescence and colorimetric dual-signal sensing platform was constructed for D-penicillamine detection, which could detect D-penicillamine in the 1-20 μM and 2-50 μM ranges with the limit of detection (LOD) values of 0.46 μM and 1.38 μM, respectively. Furthermore, this sensing platform could also realize the intelligent RGB detection via mobile phones due to the obvious color change of the reaction system. [ABSTRACT FROM AUTHOR]

Droplet microfluidic optodes, or "droptodes", have emerged as a powerful technology for rapid detection of small ions in complex matrices. While using segmented aqueous phases provides the benefits of sample isolation, the influence of the liquid nature of the oil carrier phase has not yet been explored. In this paper, we examine the influence of microfluidic parameters on droptode efficiency, using potassium-sensitive droptodes as a model system. We found that while changing flow rates on device does not change droptode performance, both channel geometry and droplet size significantly impact droptode efficiency. Specifically, enhanced mixing of the droplets leads to faster equilibration on device and lowers limits of detection by about one order of magnitude. We also found that increasing the size of the sample droplet, at the expense of the size of the oil carrier/sensing phase, leads to higher sensitivity in the linear region of the droptode. These easily manipulated properties will allow one device to potentially be adapted for several different applications, based upon the type and concentration range of measurement required. [ABSTRACT FROM AUTHOR]

Transition metals have a long history in heterogeneous catalysis. Noble or precious transition metals have been widely used in this field. The advantage of noble and precious metals is obvious in 'heterogeneous catalysis'. However, the choice of Earth abundant metals is a sustainable alternative due to their abundance and low cost. Preparing these metals in the nanoscale dimension increases their surface area which also increases the catalytic reactions of these materials. Nevertheless, metals are unstable in the nanoparticle form and tend to form aggregates which restrict their applications. Loading metal nanoparticles (MNPs) into highly porous materials is among the many alternatives for combating the unstable nature of the active species. Among porous materials, highly crystalline metal–organic frameworks (MOFs), which are an assembly of metal ions/clusters with organic ligands, are the best candidate. MOFs, on their own, possess catalytic activity derived from the linkers and metal ions or clusters. The catalytic properties of both non-noble metal nanoparticles (MNPs) and MOFs can be improved by loading non-noble MNPs in MOFs yielding MNP@MOF composites with a variety of potential applications, given the synergy and based on the nature of the MNP and MOF. Here, we discussed the synthesis of MNP@MOF materials and the applications of non-noble MNP@MOF materials in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Diglycolamide extractants, and in particular N,N,N′,N′-tetraoctyl diglycolamide (TODGA), are currently under investigation for use in nuclear fuel reprocessing by liquid–liquid separations. Several processes, such as ARTIST, i-Sanex, and EURO-GANEX processes, have been developed around the TODGA extractant. The solvent typically combines TODGA with a modifier in an alkane diluent. Due to the high radiation produced by the actinides and fission products present in the fuel, radiolytic degradation can greatly alter the chemistry of these solutions. The radiolysis and hydrolysis of the diglycolamide-based extractant was investigated. The effects of the presence of 1-octanol as phase modifier in organic phase and nitric acid concentration in aqueous phase were investigated. Nitric acid provides a slight protective effect, whereas the presence of 1-octanol seems to have a slight sensitizing effect. Fukui function calculations were done to supplement the experimental data and give an improved understanding of the behaviour of TODGA organic solutions after radiolysis. An increase in nitric acid concentration protects TODGA from radiolysis as nitrate absorbs the radicals. The slight sensitizing effect of 1-octanol is due to a combination of several competitive effects: a protective effect from TODGA–octanol adducts and a sensitizing effect from an increase in the water concentration in the organic phase, which produces ˙OH radicals. Lanthanide extraction was performed with irradiated solutions to identify the degradation products that complex metal ions. Among the identified degradation products in solution, compounds retaining the diglycolamide skeleton and [2-(dioctylamino)-2-oxoethoxy]acetic acid participate in the lanthanide complexation to form mixed Ln-degradation product-TODGA complexes. In contrast, 2-hydroxy-N,N-dioctylacetamide acts more like a phase modifier rather than directly complexing lanthanide ions. [ABSTRACT FROM AUTHOR]

Molecular ferroelectrics as a class of functional materials have broad applications in information storage and molecular devices. It is necessary to expand the ferroelectric family or modulate ferroelectricity in order to better utilize ferroelectric materials. Herein, two pairs of chiral tetranuclear copper-clusters containing different halogen anions formulated as [Cu4(L2−)2(HL−)2(MeOH)2]2+·2Cl− (complexes 1 and 2) and [Cu4(L2−)2(HL−)2(H2O) (MeOH)]2+·2Br− (complexes 3 and 4) were successfully synthesized through a pair of chiral Schiff-base ligand L / D -H2L (H2L = 2-(((1-hydroxy-3-phenylpropan-2-yl)imino)-methyl-6-methoxyphenol)), coordinate with CuCl2·2H2O and CuBr2 respectively. The solid-state circular dichroism (CD) spectra excellently demonstrate that complexes 1 and 2, and complexes 3 and 4 are a pair of enantiomers, respectively. It is noteworthy to mention that the halogen anions contained in the crystal structure have a crucial effect on the ferroelectricity of tetranuclear copper-clusters. Complexes 1 and 3 can exhibit different ferroelectricity, which is verified by the hysteresis loop. When test frequency and voltage are 1 Hz and 800 V, respectively, the remanent polarization and coercive field of complex 1 are 0.68 μC cm−2 and 1.43 kV cm−1, respectively, while those of complex 3 are 0.12 μC cm−2 and 3.45 kV cm−1, respectively. The ferroelectric performance of complex 1 is superior to that of complex 3. Moreover, polarization is at the same level to that of classical ferroelectric material Rochelle salt (0.25 μC cm−2) and is better than some ferroelectrics incorporating halogen in coordination compounds. Importantly, this study provides a route to enlarge the ferroelectric material family or further modulate ferroelectricity by altering halogen anions in the crystal structure. [ABSTRACT FROM AUTHOR]