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In this study, we report a new syringe aldehyde-derived hydrazinyl-imidazole based fluorescent sensor (L) for sensitive detection of different inorganic quenchers (halide ions, bicarbonate ion, sulphide ion and transition metal ions). The chromophore (L) was obtained in good yield by the 1:1 condensation reaction of 2-hydrazino-4,5-dihydroimidazole hydrobromide and 4-hydroxy-3,5-dimethoxy benzaldehyde. L exhibited strong fluorescence in the visible region (around 380 nm) and its interaction with different quenchers was studied in details via fluorescence technique. For the halide ions series, its sensitivity is higher for NaF (Climit = 4 × 10− 4 M) than for NaCl while the fluorescence quenching occurred mainly through a dynamic process. Similar considerations were observed for HCO3− and S2− quencher too, when static and dynamic quenching take place simultaneously. Regarding transition metal ions, at a fixed ion concentration (4 × 10− 6 M), best performance was achieved for Cu2+ and Fe2+ (fluorescence intensity was reduced by 79% and 84.9% respectively), while for other metal ions, the sensor performance was evaluated and found to be very less (< 40%). Thus, minimum detection limits (10− 6 – 10− 5 M range) recommended the use of such derivatives as highly sensitive sensors capable to monitor delicate changes in varied environments. [ABSTRACT FROM AUTHOR]

The controllable synthesis of non-classical nucleobase pairs that can mimic partial biological behavior is very important for the in-depth study of DNA or RNA. Here, three different interaction modes of uracil–uracil base pairs (U-motif) have been explored in the coordination complexes of 2′-deoxyuracil 5′-monophosphate (dUMP) and uracil 5′-monophosphate (UMP) with transition metal ions by single crystal structural analysis and DFT calculations for the first time. The results indicate that the structural diversity of non-classical nucleobase pairs may be a bank of supramolecular interactions, which will contribute to the study of supramolecular chemistry and biochemistry. [ABSTRACT FROM AUTHOR]

Polyoxometalates (POMs) exhibit unique structural characteristics and excellent physical and chemical properties, which have attracted significant attention from scholars in the fields of anticancer research and chemotherapy. Herein, we successfully synthesized and structurally characterized two novel polyoxovanadates (POVs), denoted as POVs-1 and POVs-2, where [M(1-vIM)4]2[VV4O12]·H2O (M: NiII and MnII, 1-vinylimidazole abbreviated as 1-vIM) serve as ligands. The two POVs are isomeric and consist of fundamental structural units, each comprising one [V4O12]4− cluster, two [M(1-vIM)4]2+ cations, and one water molecule. Subsequently, we evaluated the cell viability of human hepatocellular carcinoma (HepG-2) cells treated with the synthesized POVs using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazoliumbromide) assay. And the changes in cell nucleus morphology, mitochondrial membrane potential (Δψm), and reactive oxygen species levels in HepG-2 exposed to POVs were monitored using specific fluorescent staining techniques. Both hybrid POVs showed potent inhibitory activities, induing apoptosis in HepG-2 cells along with significant mitochondria dysfunction and a burst of reactive oxygen species. Notably, the inhibitory effects of POVs-2 were more pronounced than those of POVs-1, which is primarily attributed to the different transition metal ions present. These findings underscore the intricate relationship between the metal components, structural characteristics, and the observed antitumor activities in HepG-2 cells. [ABSTRACT FROM AUTHOR]

For its important roles in biology, nitrogen monoxide (·NO) has become one of the most studied and fascinating molecules in chemistry. ·NO itself acts as a "noninnocent" or "redox active" ligand to transition metal ions to give metal–NO (M–NO) complexes. Because of this uncertainty due to redox chemistry, the real description of the electronic structure of the M–NO unit requires extensive spectroscopic and theoretical studies. We previously reported the Ni–NO complex with a hindered N3 type ligand [Ni(NO)(L3)] (L3− denotes hydrotris(3-tertiary butyl-5-isopropyl-1-pyrazolyl)borate anion), which contains a high-spin (hs) nickel(II) center and a coordinated 3NO−. This complex is very stable toward dioxygen due to steric protection of the nickel(II) center. Here, we report the dioxygen reactivity of a new Ni–NO complex, [Ni(NO)(I)(L1″)], with a less hindered N2 type bis(pyrazolyl)methane ligand, which creates a coordinatively unsaturated ligand environment about the nickel center. Here, L1″ denotes bis(3,5-diisopropyl-1-pyrazolyl)methane. This complex is also described as a hs-nickel(II) center with a bound 3NO−, based on spectroscopic and theoretical studies. Unexpectedly, the reaction of [Ni(NO)(I)(L1″)] with O2 yielded [Ni(κ2-O2N)(L1″)2](I3), with the oxidation of both 3NO− and the I− ion to yield NO2− and I3−. Both complexes were characterized by X-ray crystallography, IR, and UV–Vis spectroscopy and theoretical calculations. [ABSTRACT FROM AUTHOR]

[Display omitted] To develop Co-free LiNiO 2 -based layered cathode materials is crucial for meeting the demands of the lithium-ion batteries with high energy density, long cycling life, and low cost. Herein, the LiNi 1 -x-y Al x Mg y O 2 materials are synthesized by the solid–solid interface elemental interdiffusion strategy. It is elucidated that the Mg2+ and Al3+ ions are mainly doped in the Li slabs and transition metal slabs, respectively, leading to the alteration of the crystal lattice. Furthermore, the incorporation of the Mg2+ ions may induce more Ni2+ ions formed in the transition metal slabs, which would have great impact on the electrochemical performance of the materials. The LiNi 1 -x-y Al x Mg y O 2 materials with optimized Mg/Al co-doping exhibit much better electrochemical performance than the pristine LiNiO 2 and Al-doped LiNiO 2 materials, including cycling stability and rate capability. The in-situ XRD characterization and structural analysis show that stabilization of the crystal structure, preservation of the integrity of the secondary particles, and enlargement of the interlayer spacing by the Mg/Al co-doping are the main factors responsible for the superior performance of the materials. The Mg/Al co-doping strategy might be the promising approach for the design of the cobalt-free nickel-rich materials. [ABSTRACT FROM AUTHOR]

Coordination polymers of transition metal ions are fascinating and important to coordination chemistry. One of the ligands known to form particularly interesting coordination polymers is 3,3′,5,5′-tetramethyl-4,4′-bipyrazole (Me4bpzH2). Group 11 metal(I) ion coordination polymers, other than those of copper(I), are relatively easy to handle because of their low reactivity towards dioxygen and moisture. However, the known silver(I) coordination polymers often have poor solubility in common solvents and so cannot be easily analyzed in solution. By using a tetramethyl substituted bipyrazole ligand, we have synthesized more soluble silver(I) complexes that contain the trifluoromethyl group in the coordinated ions CF3CO2− and CF3SO3− in [Ag(CF3CO2)(Me4bpzH2)] and [Ag(CF3SO3)(Me4bpzH2)]. We determined both structures by single-crystal X-ray analysis at low temperatures and compared them in detail. Moreover, we investigated the solution behavior of these coordination polymers by 1H-NMR, IR, Raman, UV–Vis spectroscopies, and their low-temperature, solid-state photoluminescence. The high-energy band at ~330 nm corresponded to ligand-centered (bipyrazole) fluorescence, and the low-energy band at ~400 nm to ligand-centered phosphorescence resulting from the heavy atom effect. [ABSTRACT FROM AUTHOR]

The reaction of hydroxybenzoates with divalent first row transition metal ions afforded four mononuclear complexes, [M(OH2)6](dhbzc)2·2H2O (M = Co2+, 1 or Mn2+, 2), [Ni(OH2)6](hbzc)2·2H2O (3) and [Ni(OH2)5(hbzc)](hbzc)·3H2O (4) (where dhbzc− = 2,6-dihydroxybenzoate and hbzc− = 4-hydroxybenzoate). The complexes were characterized by single crystal and powder X-ray diffraction analyses, infrared spectroscopy, and thermogravimetric analysis. Results showed that the hydrogen bonds present in dhbzc− impaired its coordination to Co2+ and Mn2+. Thereafter, Hirshfeld surface analyses (HS) and 2D fingerprint plots were used to investigate the intermolecular contacts in 1–4. The offset π···π stacking of the dhbzc− counterions in 1 and 2 lead to C···C close contacts over C···H/H···C ones. Complexes 3 and 4 presented the usual herringbone aromatic-based packing for the hbzc− rings with a predominance of C···H/H···C close contacts. The existence of water molecules in the crystal lattices of 1–4 was determined by TG analyses, which proved the presence of coordinated and uncoordinated water molecules. The thermal decomposition patterns were analyzed in light of the percentage of the strongest intermolecular close contacts. [ABSTRACT FROM AUTHOR]

As a new type of smart material, color-changing materials have great application potential in the fields of optical storage information and optical devices. The viologen ligand 1,1'-bis(4-carboxybenzyl)-4,4'-bipyridine dichloride (H2 BpybcCl2 ) with a flexible skeleton is used as a functional ligand, and the transition metal ion Mn2+ and Cd2+ self-assembled to synthesize two isostructural coordination polymers [Mn(Bpybc)Cl2·H2O]n (1) and [Cd(Bpybc)Cl2 ·4H2O]n (2) . X-ray single crystal diffraction showed that the two compounds had a one-dimensional chain structure. Viologen free radicals were generated by light-induced electron transfer under the irradiation of ultraviolet light, and both compounds showed obvious photochromic behavior. [ABSTRACT FROM AUTHOR]

Bismuth (Bi3+)‐included lead‐free metal halide (LFMH) materials attract much attention in lighting, display, photodetectors, X‐ray detectors, and photovoltaic fields, due to the tunable luminescence and optoelectronic performance in response to crystal and electronic structure, morphology, and particle sizes. This review summarizes Bi3+‐included LFMH materials about their preparation approach, crystal and electronic structure properties, luminescence performance, and emerging applications. Notably, Bi3+ ions not only can act as framework cation to construct stable LFMH structure, but can also incorporate into LFMH materials as activators or sensitizers to generate remarkable luminescence tuning and band engineering. The Bi3+ effect on the luminescence and optoelectronic properties of LFMH materials, including, promotion of exciton localization, enhancement of light absorption in near‐ultraviolet region, action as sensitizer ions to transfer energy to rare earth or transition metal ions and emission of highly‐efficient light is systematically summarized. The proposed structure‐luminescence relationship offers guidance for the optimization of current Bi3+‐included LFMH materials and the exploitation of new LFMH derivatives. [ABSTRACT FROM AUTHOR]

[Display omitted] • The interaction of H 2 midp (L) with several +2 metal ions was studied. • 1:1 M−L species were detected in the potentiometric titrations for most metal ions. • For Cu(II), a trinuclear complex [M 3 (midp) 2 ] 2 + was detected in solution. • Polynuclear coordination compounds based on Zn(II), Cu(II) and Ni(II) were prepared and characterized. • 1D coordination polymers were crystallized. Six new polynuclear coordination compounds based on 3 d transition metal ions (Cu(II), Ni(II)) and Zn(II) with the flexible dicarboxylate compound N -methyliminodipropionic acid (H 2 midp) were prepared and characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. Four of these compounds are 1D coordination polymers, namely [Cu(midp)(H 2 O)] (1), [Cu 3 (midp) 2 (H 2 O) 4 ](NO 3) 2 ·6H 2 O (2) [Cu 3 (midp) 2 (H 2 O) 4 ](CF 3 SO 3) 2 ·4H 2 O (3) and [NaZn(Hmidp) 2 ](CF 3 SO 3) (6). The structural analysis revealed that the chain structure of 1 is composed of [Cu(midp)(H 2 O)] units connected by the free carboxylato oxygen atom of neighbor units, in an alternate fashion. In 2 and 3 , on the other hand, there are two [Cu(midp)H 2 O] units, connected by a central Cu(II) ion coordinating again to the free oxygen atom of the carboxylato groups. The Zn(II) compound is heteronuclear and the complex adopts a 1D cationic polymeric structure with zinc and sodium ions connected by two Hmidp– anions. The two other compounds are dinuclear, [Cu 2 (Hmidp) 2 (μ -H 2 O) 2 (H 2 O) 2 ](CF 3 SO 3) 2 ·6H 2 O (4) and ([Ni 2 (midp) 2 (H 2 O) 4 ] (5). Additionally, a Co(II) and a Cu(II) coordination compound were obtained with the same ligand and characterized by IR spectroscopy, thermal analysis and elemental analysis including metal quantification. For the copper compound the formula [Cu(Hmidp)](ClO 4)·3H 2 O (7) is proposed while for the Co(II) compound (8) the proposed formula is [Co(midp)(H 2 O) 2 ]. Solution studies of the ligand–M(II) systems (M(II) = Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb) were also carried out in order to help the selection of the best synthetic conditions and also to complement the structural knowledge in the exploration of the potential formation of coordination polymers in these systems. [ABSTRACT FROM AUTHOR]

• Synthesis of Mg 0.5 Zn 0.5 Mn 1.95 (Fe/Co/Ni) 0.05 O 4 by auto-combustion method. • Structural, morphological, optical, dielectric analysis on the prepared samples. • High dielectric constants and low losses are suitable for communication devices. This work aimed at synthesizing Mg 0.5 Zn 0.5 Mn 1.95 (Fe/Co/Ni) 0.05 O 4 nanoparticles using sol–gel auto-combustion method. Structural studies (XRD, Rietveld, Raman) confirmed the tetragonal spinel structure with I41/amd space group and average crystallite size ranged between 18–22.8 nm. The morphologies and compositions of these nanoparticles were studied using SEM and EDX. UV–Vis spectra demonstrated significant enhancement in the absorbance values. The estimated optical band gaps vary between 1.6 to 1.77 eV. Frequency-dependent dielectric and impedance spectroscopic studies (at room temperature) reveal exciting results. Thus, tailoring of dielectric properties and optical band gaps of these transition metals doped Mg-Zn manganite nanoparticles may find potential applications in optoelectronics devices. [ABSTRACT FROM AUTHOR]

• A new Pd(II) complex of biphenol-ethylenediamine ligand L and five complexes of L with Ni2+, Cd2+, Cu2+, Pd2+ were compared. • Roles of solvent molecules and molecular conformation (driven by the metal geometry) in solid state assembly were studied. • Hirshfeld surface analysis, 2D fingerprint plots and energy frameworks assessed the interactions within crystal packings. • The solvent plays a minor role in the solid state assembly, compared to the molecular conformation driven by the metal ion. A new Pd(II) complex of the previously reported ligand N,N′-bis[(2,2′-dihydroxybiphen-3-yl)methyl]-N,N′-dimethylethylenediamine (L) was obtained from N,N -dimethylformamide/water. The roles in the solid state assembly of solvent molecules and molecular conformation were studied by comparing six complexes of L containing different metal centers (Ni(II), Cd(II), Cu(II), Pd(II)). Hirshfeld surface analysis, 2D fingerprint plots and energy frameworks calculations were used to investigate the intermolecular interactions within the crystal packings. Pd(II) and Ni(II) complexes arrange to form ribbons, while Cd(II) and Cu(II) complexes form 3D networks. Interactions between complexes and solvent molecules in the previously reported Pd(II) complex are replaced by complex-complex interactions in the new Pd(II) complex, while butanol and methanol are interchangeable in the interactions within the Ni(II) complexes. The present study suggested that the solid state assembly of these systems is mainly driven by the molecular conformation, that depends in turn by the metal ion involved, while the solvent only plays a minor role. [Display omitted] [ABSTRACT FROM AUTHOR]

CsPbCl3 nanocrystals (NCs) exhibit vast potential in high‐energy emission applications owing to their wide‐bandgap characteristics, that differ from those of CsPbBr3 and CsPbI3 NCs. Recently, significant developments related to CsPbCl3 NCs have been achieved with regard to tunable emission, luminescence efficiency, and stability, along with their use as hosts for the sensitization of transition metals or rare‐earth ions. This review describes the important factors that influence the optical properties of CsPbCl3 NCs based on factors such as crystal structure, defect compositions, and surface states. In addition, fundamental strategies for improving the performance of CsPbCl3 NCs are discussed, including direct synthesis, post‐treatment methods, and cation doping by either single‐ or co‐doping. The prospects of CsPbCl3 NCs for related optoelectronic applications are reviewed, with emphasis on practical hurdles that need to be overcome in the future. [ABSTRACT FROM AUTHOR]

CsPbCl3 nanocrystals (NCs) exhibit vast potential in high‐energy emission applications owing to their wide‐bandgap characteristics, that differ from those of CsPbBr3 and CsPbI3 NCs. Recently, significant developments related to CsPbCl3 NCs have been achieved with regard to tunable emission, luminescence efficiency, and stability, along with their use as hosts for the sensitization of transition metals or rare‐earth ions. This review describes the important factors that influence the optical properties of CsPbCl3 NCs based on factors such as crystal structure, defect compositions, and surface states. In addition, fundamental strategies for improving the performance of CsPbCl3 NCs are discussed, including direct synthesis, post‐treatment methods, and cation doping by either single‐ or co‐doping. The prospects of CsPbCl3 NCs for related optoelectronic applications are reviewed, with emphasis on practical hurdles that need to be overcome in the future. [ABSTRACT FROM AUTHOR]

A new magnetic compound NaNiFe2(VO4)3 has been obtained by the solid-phase synthesis and studied by X-ray diffractometry, nuclear gamma resonance, and magnetometry. The crystal structure of multicomponent vanadate is described by a triclinic symmetry space group P1. The unit cell contains six nonequivalent mixed cationic positions occupied by different-valence ions of transition metals, iron Fe3+ and nickel Ni2+, which facilitates the implementation of a state with the local charge neutrality violation. In addition, two types of iron atom sites have been found, which have an oxygen environment in the form of octahedra and square pyramids with their nonequiprobable population by iron and nickel. The temperature and field dependences of the magnetization have been found to be typical of a paramagnet containing ferromagnetic clusters in a wide temperature range. [ABSTRACT FROM AUTHOR]

X-ray crystal structures of multinuclear Cu(II) and Ni(II) complexes with 6+6 macrocyclic amine show variable coordination numbers of metal ions and various conformations adopted by the ligand. In Cu(II) complexes the macrocycle provides N3 donor set for each metal ion, while in the Ni(II) complex alternating N3 and N4 environments of the metal ions are observed. [Display omitted] An extended macrocyclic amine L derived from the [6+6] condensation of trans-1,2- diaminocyclohexane and 2,6-diformylpyridine contains 18 nitrogen atoms in its main cycle. All of these atoms can be engaged in the formation of polynuclear complexes with transition metal ions and the macrocycle L is able to bind six Cu(II), Ni(II) or Zn(II) ions within its interior. X-ray crystal structures of these complexes indicate variable coordination numbers of metal ions as well as various conformations adopted by the macrocyclic ligand. In the hexanuclear Cu(II) complex with coordinated nitrate anions Cu(II) ions are hexacoordinate and exhibit highly distorted octahedral geometry, while in analogous complexes with coordinated sulphate anions Cu(II) ions are pentacoordinate of distorted square pyramid geometry. Both complexes are relatively symmetric having (approximate) S 6 axis and adopt a circular doughnut shape with a central void not occupied by metal ions. The NMR spectrum of the zinc(II) derivative also reflects the symmetrical coordination. In contrast, the macrocycle L is squeezed and less symmetric in the octanuclear chloride derivative where two additional Cu(II) ions are linked to a hexanuclear macrocyclic unit via chloride bridges. The macrocycle is also squeezed in the hexanuclear Ni(II) complex containing metal ions of approximate octahedral geometry. In all three Cu(II) complexes the macrocycle provides N 3 donor set for each metal ion, while in the Ni(II) complex alternating N 3 and N 4 environments of the metal ions are observed. [ABSTRACT FROM AUTHOR]

Heteronuclear alcoholate complexes [M{Al(OiPr)4}2(bipy)] (2‐M, M = Fe, Co, Ni, Cu, Zn) and [M{Al(OcHex)4}2(bipy)] (3‐M, M = Fe, Co, Ni, Zn) are formed by adduct formation of [M{Al(OiPr)4}2] (1‐M, M = Fe, Co, Ni, Cu, Zn) with 2,2'‐bipyridine and transesterification reaction with cHexOAc. According to crystal structure analyses, in 2‐M and 3‐M the central transition metal ion M2+ is coordinated by two chelating Al(OR)4– moieties and one bipyridine ligand in an octahedral arrangement. Treating 1‐Cu with 2,2'‐bipyridine leads to a reduction process, whereat the intermediate [Cu{Al(OiPr)4}(bipy)2][Al(OiPr)4] (4) could be structurally characterized. During conversion of the iso‐propanolate ligands in 1‐Cu to cyclohexanolate ligands, Cu2+ is reduced to Cu+ forming [Cu{Al(OcHex)4}(py)2] (5). UV/Vis‐spectra and results of thermolysis studies by TG/DTA‐MS are reported. [ABSTRACT FROM AUTHOR]

A series of novel functionalized p-tert-butyldihomooxacalix[4]arene mono-Schiff bases were conveniently synthesized by two-step reaction process. The synthetic rout included alkylation of p-tert-butyldihomooxacalix[4]arene with O-chloroalkoxy-substituted benzaldehydes and sequential condensation with 2-hydroxybenzohydrazide, 2-picolinohydrazideand aminothiourea. The single crystal structures of two p-tert-butyldihomooxacalix[4]arenederivatives were determined by X-ray single crystal diffraction method. The coordination abilities of dihomooxacalix[4]arene mono-Schiff bases towards transition metal ions were preliminarily investigated by UV-Vis spectra. [ABSTRACT FROM AUTHOR]

Copper and nickel complexes of a highly fluorescent morpholine derivative were synthesized and characterized using 1H NMR, IR, HR-MS as well as single crystal X-ray crystallography. A morpholine substituted methyl 3-hydroxy-2-naphthoate was synthesized. The morpholine derivative displayed an intense fluorescence. Owing to the presence of suitable donor atoms, it was employed for the detection of transition metal ions. The crystals of copper and nickel complexes of the fluorescence active ligand were grown via vapor diffusion method. The ligand structure and its metal complexes were characterized using 1H NMR, IR, HR-MS and single crystal X-ray crystallography. The synthesized ligand displayed selective turn-off fluorescence response in the presence of Cu2+ and Ni2+ ions. Fluorescence active letters were encoded successfully on filter paper utilizing metal complexes as a tool towards digital writing. [ABSTRACT FROM AUTHOR]

Two new Cu(II) and Zn(II) Crystal Structures based on Pyrazolone are reported, which displays good antibacterial properties. [Display omitted] • HPMBP was synthesized successfully via the Friedel-Crafts reaction. • [Cu(HPMBP)(2,2′-bpy)(Cl)]·H 2 O and [Zn(HPMBP)(2,2′-bpy)(Cl)]·H 2 O were synthesized. • Cu(II) and Zn(II) ions exhibit a square pyramidal configuration. • The Zn-based complex has better antimicrobial properties than HPMBP. • The Cu-based complex has better antimicrobial properties than HPMBP. 4-Benzoyl-3-methyl-1-phenyl-5-pyrazolone (HPMBP) was synthesized via the Friedel–Crafts reaction and characterized through 1H NMR spectroscopy, Infrared spectroscopy and Electrospray ionization time-of-flight(ESI-TOF). The Cu(II) and Zn(II) coordination complexes, namely, [Cu(HPMBP)(2,2′-bpy)(Cl)]·H 2 O(1) and [Zn(HPMBP)(2,2′-bpy)(Cl)]·H 2 O(2), were synthesized in CH 3 OH(HPMBP:2,2′-bipyridine:M = 1:1:1, M = Cu, Zn). Single crystal X-ray diffraction(SCXRD) studies show that Cu(II) and Zn(II) exhibit a distorted square pyramidal configuration through two oxygen atoms of HPMBP, two cis -nitrogen atoms of 2,2′-bipyridine and monodentate chloride ion. Moreover, the Hirshfeld surface analysis of the in complexes was performed using crystallographic calculations. Furthermore, the antibacterial activities of 1 and 2 are more potent than HPMBP, in particular, the antimicrobial properties of 2 are better than those of 1. Scanning electron microscopy (SEM) indicated that 1 had a regular strip shape, while 2 had an irregular circular shape. Our work provides a theoretical basis for studying the antibacterial activity of transition metal ion complexes. [ABSTRACT FROM AUTHOR]

Three novel metal-organic complexes, formulated as [Cu 2 (2-HBA) 2 (bimb) 4 ] (1), {[Cd(CEDA)(bimb)]·H 2 O} n (2), and {[Ag 2 (bimb) 2 ]·(1,4-CDA)·13H 2 O} (3) (bimb = 1,2-bis((1 H -imidazole-1-yl)methyl)benzene; 2-HBA = 2-hydroxybenzoic acid; CEDA = cyclohex-4-ene-1,2-dicarboxylic acid; 1,4-CDA = cyclohexane-1,4-dicarboxylic acid), were synthesized by self-assembly of mixed ligands with Cu(II), Cd(II), and Ag(I) under hydrothermal conditions and characterized by means of single-crystal X-ray diffraction, X-ray powder diffraction, infrared spectra, thermogravimetric analysis, fluorescence spectra and UV–vis absorption spectra. 1 is shown as a 0D structure, which is formed by Cu2+, 2-HBA ligands and bimb ligands. 2 displays a 1D ladder structure, which is built by Cd2+, CEDA ligands and bimb ligands, and it is assembled into 2D structure by hydrogen bonding. 3 possesses a 0D [Ag(bimb)] 2 dimer which is assembled into 3D structure by the Ag O weak interaction and hydrogen bonding. Interestingly, a rare 13-core water cluster participates in forming the network of 3. The UV–vis spectrum and luminescence properties were also studied and discussed. Image 1 • Three novel metal-organic complexes were hydrothermal synthesized. • A rare 13-core water cluster participates in forming the network of compound 3. • The three diverse structures are mainly attributed to the weak interactions. • The UV–vis spectrum and luminescence properties were studied. [ABSTRACT FROM AUTHOR]

Efficient oxynitride phosphors CaSi 2 O 2 N 2 :Eu2+, Ce3+ for application as down-conversion luminescent materials in wLEDs were prepared from the precursor Ca 3 (PO 4) 2 :Eu3+, Ce4+ at the relatively low temperature (1400 °C), as well as a kind of novel phosphor of Ca 2 AlSi 3 O 2 N 5 : Eu2+/Mn2+ was synthesized with CaCN 2 as calcium resource. The structures and photoluminescent properties of oxynitride phosphors doped with rare earth and transition metal ions were systematically researched. The results indicate that the photoluminescence (PL) intensity can be highly improved when Eu2+/Ce3+ ions are doped with appropriate amounts in CaSi 2 O 2 N 2 matrix. The rare earth or transition metal ions occupy two different lattice sites in the Ca 2 AlSi 3 O 2 N 5 host according to the PL spectra. • The CaSi 2 O 2 N 2 : nEu2+, mCe3+ phosphors have been successfully synthesized from the precursor Ca 3 (PO 4) 2. • Novel phosphors Ca 2 AlSi 3 O 2 N 5 , a thermally stable phase of CaAlSiN3, were convieniently obtained with CaCN 2 as raw materials. • Synthesis temperature only requires 1400°C, neither vacuum box or high-pressure nitrogen is required. • The PL intensity can be highly improved when Eu2+ ions are doped with appropriate amounts of Ce3+ in CaSi 2 O 2 N 2. • The PL and PLE spectra data analysis confirms that Ca2+ ions have two different kinds of sites in the Ca 2 AlSi 3 O 2 N 5 host. [ABSTRACT FROM AUTHOR]

• Computational model of Sr 3 MgSi 2 O 8-σ N σ were built and investigated. • The substituting nitrogen ions tended to be spreading among the lattice. • The energy needed for one oxygen substituted by one nitrogen is about 89.50 eV. • This work is useful for understanding nitrogen replacing oxygen in Sr 3 MgSi 2 O 8-δ. In this work, influence of the nitrogen substituting for oxygen on the crystal structures and electronic band structures of Sr 3 MgSi 2 O 8-σ N σ (σ = 0, 0.125 and 0.250) materials had been investigated by the first-principles calculation. For the initial Sr 3 MgSi 2 O 8 without nitrogen substitution, the band gap is about 5.889 eV between the conduction band and valence band. Analysis of its density of states (DOS) indicates that the conduction band is mainly constituted by Sr- d orbit. The valence band is mainly constituted by O- p orbit. After the nitrogen substituting for oxygen occurs, the band gap gradually decreases to 4.421 eV in the case σ = 0.250. Top of the valence band is still locating near 0 eV while bottom of the conduction band drops down to 4.421 eV. On the other hand, it can be observed that the N- p orbit hybridized into the top of the valence band which induced a new band above the O- p orbit. For Sr 3 MgSi 2 O 8-σ N σ materials with rare earth ions or transition metal ions serving as luminescence centres, this condition would influence the charge transfer process between the host materials and the luminescence centres. In addition, the energy needed for the substitution of one nitrogen anion for one oxygen anion is calculated to 89.50 eV. This illuminates clearly that the preparation condition of nitrogen oxide compounds is harsh. This work is helpful for better understanding the influence of nitrogen substituting for oxygen on the crystal structures and electronic band structures of Sr 3 MgSi 2 O 8-σ N σ materials. [ABSTRACT FROM AUTHOR]

The interaction of a poly-functional ligand derived from o-vanillin and 2-thiophenemethylamine (oVATPNH2) with transition metal ions Cu(ii) and Zn(ii) leads to the formation of stable coordination compounds, namely [Cu(oVATPNH2)2] and [Zn(oVATPNH2)2]. Their crystal structures have been determined by X-ray diffraction methods. Two molecules of the deprotonated ligand acting in a bidentate fashion build a nearly square planar environment around Cu(ii) and a distorted tetrahedral coordination arrangement for Zn(ii). The complexes were characterized by spectroscopic techniques, including solid state FTIR, Raman, EPR and diffuse reflectance and solution UV-vis and EPR. Their thermal behavior has been analyzed by means of TGA and DTA. DFT theoretical studies, using computational methods based on DFT, were employed to assist the interpretation and assignment of spectroscopic data. Cytotoxicity assays against two human breast cancer cell lines, namely MCF-7 and MDA-MB-231, revealed an enhancement of the effectiveness of the complexes as compared with both the ligand and the free metal ions. The results for the copper compound are promising, as its cytotoxic effect was stronger than the reference metallodrug cisplatin in both cancer cell lines tested. [ABSTRACT FROM AUTHOR]

Abstract One hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstate, [Cu(Himi) 4 ][(pz) 0.5 {Cu 3 Na 3 (AsW 9 O 33) 2 }](Hpz) 3 ·H 2 O (1), (pz = pyrazine, imi = imidazole) has been synthesized and structurally characterized. Basic frameworks of 1 is constructed from sandwich-type [(pz) 0.5 {Cu 3 Na 3 (AsW 9 O 33) 2 }] anions, [Cu(Himi) 4 ] complex, free protonated pz ligands and water molecule. The transition metal ions Cu2+ and Na+ in the central belt connect alternately in an edge-sharing mode forming a hexa-nuclear ring. Pz ligand and [Cu(Himi) 4 ] as bridge connect to {Cu 3 Na 3 (AsW 9 O 33) 2 } fragments, respectively, which forms a enormous ten-members ring, then leading to constitute a novel 2D ABAB arrangement layer structure. The pz as bridge to link two hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstates is first observed. Additionally, compound 1 shows excellent photocatalytic activity for the degradation of MB and RhB dye under UV irradiation. The photocatalytic reaction mechanism has been also investigated. In addition, the electrochemical and electrocatalytic activity upon the reduction of H 2 O 2 also has been studied. Graphical abstract Unlabelled Image Highlights • A new 2D hexa-nuclear ring Cu/Na-substituted sandwich-type arsenotungstate has been synthesized under hydrothermal conditions. • Compound 1 has excellent photocatalytic activity on MB and RhB. • Compound 1 displays better electrochemical and electrocatalytic behaviors. [ABSTRACT FROM AUTHOR]

Graphical abstract Six metal polycarboxylate complexes tuned by N-donor co-ligands and transition metal ions have been successfully synthesized and structurally characterized. The photoluminescent and magnetic properties of partial complexes were studied. Abstract Six transition metal–organic complexes based on 3,5-di(3,4-dicarboxylphenyloxy)benzoic acid (H 5 L) and different N-donor co-ligands, namely, Cu(H 3 L)(2,2′-bpy)·H 2 O (1), Zn 2 (HL)(2,2′-bpy) 2 (2), Cd 2 (HL)(2,2′-bpy) 2 (H 2 O) (3), Cd 2 (HL)(phen) 4 ·5H 2 O (4), Cu(H 3 L)(phen) (5), and Cu(H 3 L)(4,4′-bpy)·H 2 O (6) (2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine), were successfully synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Complexes 1 and 5 possess discrete zero-dimensional (0D) structures which are further assembled into three-dimensional (3D) supramolecular frameworks by hydrogen-bonding interactions and π–π stacking interactions. Complexes 2 and 3 display similar 3D frameworks with different topologies. Complex 4 shows a one-dimensional (1D) chain which is further connected into a two-dimensional (2D) supramolecular layer via π–π stacking interactions. Complex 6 exhibits a 1D chain which is further extended into a 3D supramolecular network through hydrogen-bonding interactions. The H 5 L ligand is partially deprotonated in 1 – 6. The N-donor co-ligands and transition metal ions have important effects on the architectures of 1 – 6. The photoluminescent properties of 2 – 4 and the magnetic properties of 1 and 6 were also studied. [ABSTRACT FROM AUTHOR]

In the current study, four new phenolic oxime ligands (HL1ox-HL4ox) containing diazo groups (-N=N-) were synthesized and used for liquid-liquid extraction of heavy metal ions [Cu(II), Ni(II), and Zn(II)]. The new compounds were characterized by analytical and spectroscopic methods. Solid-state structures of HL1ox-HL3ox were determined by single-crystal X-ray diffraction studies. Hirshfeld surface analysis of the compounds was performed to determine the contribution of different intermolecular contacts to the stability of the structures. The HL1ox-HL4ox ligands showed higher extraction performance for Cu(II) ion than Ni(II) and Zn(II) ions. The effect of pH on extraction capacity was investigated and the oxime compounds showed high extraction capacity at low pH values. The effects of the substitute groups (at the meta position of the phenol ring) on the extraction were investigated. Within the oxime ligands, the HL3ox compound exhibited higher extraction capacity for Cu(II) ions. The better extraction value of HL3ox is attributed to the weak hydrogen bond type interactions, which result in more stable complexes. [ABSTRACT FROM AUTHOR]

In this work, we studied effects of Ni 2 O 3 and Co 2 O 3 doping on crystal structures, microstructures, orthorhombic and tetragonal phase transition temperature ( T o-t ), and electrical properties of [Li 0.06 (Na 0.57 K 0.43 ) 0.94 ][Ta 0.05 (Sb 0.06 Nb 0.94 ) 0.95 ]O 3 (LNKTSN) lead-free ceramics. The experimental results showed that the Ni 2 O 3 addition with appropriate amount could shift the T o-t downwards to the room temperature, and thus obviously increasing the room-temperature piezoelectric coefficient ( d 33 ), dielectric coefficient ( ε r ) and electromechanical coupling coefficient ( k p ) of the LNKTSN ceramics. These were consistent with previous experimental results obtained in Fe 2 O 3 doped LNKTSN ceramics. On the contrary, Co 3+ doping shifted continuously the T o-t upward and deteriorated obviously piezoelectric properties of LNKTSN ceramics. Fe, Co and Ni had similar ion radii and were expected to result in the same (donor or acceptor) doping effects on electrical properties of LNKTSN ceramics. The different doping effects between Co 3+ (deterioration) and Ni 3+ or Fe 3+ (improvement) on the electrical properties of LNKTSN ceramics suggested that the coexistence of orthorhombic and tetragonal phases at room temperature due to downward shift of T o-t , rather than ion doping (donor or acceptor doping) effects was the main cause for enhanced room-temperature piezoelectric properties. This conclusion can be extended to all KNN-based materials in general, thus offering principle guide for future development of new lead-free materials with good piezoelectric properties. [ABSTRACT FROM AUTHOR]

Under hydrothermal conditions, a new two-dimensional (2D) zinc coordination polymer, [Zn(tdc)(bimm)]n, was synthesized based on thiophene-2,5-dicarboxylic acid (H2tdc) and 1,2-bis(imidazol-1'-yl)methane (bimm) mixed ligands. Single crystal X-ray structural analysis shows adjacent Zn2+ ions are connected by tdc2- anions to form a one-dimensional (1D) [ZnL]n chain in the complex. Then flexible bimm ligands expand 1D chains into a 2D layer by linking neighboring Zn2+ ions. These adjacent layers are further stacked together by direct C-H···π supramolecular interactions, generating a double-layer 2D supramolecular structure. In topology, the 2D lay could be rationalized to a uninodal 4-connected non-interpenetrated sql net with {44.62} topology. In addition, solid state properties such as thermogravimetric analysis and luminescence were also investigated. [ABSTRACT FROM AUTHOR]

With the objective of incorporating some divalent transition-metal ions in thoria and to comprehend its effect on the crystal structure, electronic as well as catalytic properties, Ni2+, Cu2+ and Cd2+ substituted thoria samples were synthesized by the epoxide gel method. Of the two concentrations investigated, 10 mol% of Ni2+, Cu2+, and Cd2+ could be substituted retaining the fluorite structure and phase separation into individual oxides was noticed for 15 mol%. The average crystallite size of thoria and 10 mol% substituted samples was 14 nm. Le-Bail structural refinements of Powder X-ray diffraction (PXRD) patterns indicated marginal increase in unit cell constant for the Cd2+ substituted sample and a decrease for Ni2+ and Cu2+ substituted samples. In addition to broadening of the band at around 460 cm-1 (F2g vibration of the fluorite), less intense band near 560-590 cm-1 emerged for all the transition-metal ion-containing samples in the Raman spectra implying the formation of oxygen defects. The absorption edge in the UV-visible spectra moved toward higher wavelength for Cd2+, Ni2+ and Cu2+ containing samples as compared to pure thoria. In addition, d-d transition was observable for Ni2+ and Cu2+ containing samples. By virtue of these changes in the electronic structure of transition-metal ion-containing samples, they were examined as catalysts for the degradation of aqueous Rhodamine- 6G (Rh-6G) dye solutions under visible radiation. [ABSTRACT FROM AUTHOR]

Two transition metal coordination polymers (CPs), namely, Cd(1,4-NDC)(py) ( 1 ), Co 2 (1,4-NDC) 2 (DMF) 2 ( 2 ) (1,4-NDCH 2 = 1,4-naphthalenedicarboxylic acid, py = pyridine, DMF = N , N -dimethylformamide) have been synthesized and characterized. Compound 1 contains one-dimensional chains, which are further linked by the NDC 2 − ligands to form a three-dimensional framework with a 5,5T2 topology network. There exist two types of left-hand helical chains interconnected to each other through the Cd(II) center in compound 1 . Although compound 2 has been reported previously, in this work the synthetic method of 2 is modified to obtain high quality crystals. In addition, the magnetic property of compound 2 is investigated, which shows the metamagnetic behavior induced by the external field. [ABSTRACT FROM AUTHOR]

The literature studies on the complexes of aminobenzoic acids, especially fenamates, with transition, post-transition and rare earth metals reveal a great interest in this subject. In this paper the binary and ternary complexes of aminobenzoic acids involving oxygen-, nitrogen- and phosphorus-donor coligands were described. We compared the complexes’ synthesis methods, their physicochemical properties, spectroscopic studies as well as composition and geometry. The complexes have been characterized in terms of their biological activity and applications as medicals, hybrid organic–inorganic materials, luminescent materials, green corrosion inhibitors, catalysts and magnetic materials. [ABSTRACT FROM AUTHOR]

Dithizone, since its discovery in 1878, has become essential in colorimetric assays for numerous transition metal ions. However, despite it being a vital reagent its coordination chemistry is not fully understood. Here we give insight into the binary complexes of dithizone, which contain two different metal ions, and the secondary complexes with Cu(ii) which can either involve reduction of the metal ion or double deprotonation of dithizone giving the self-assembled [(H-DPTC)8Cu8] and [(DPTC)4Cu4] species respectively. [ABSTRACT FROM AUTHOR]

This work describes the synthesis, anticancer activity and electron structure study of two Cu (II) complexes with coumarin-3-formyl-(3-(aminomethyl) pyridine) ligand (L) - C1 (Cu 2 L 2 (OAc) 4) and C2 (CuL 2 (NO 3) 2). The structure of C1 and C2 was confirmed by elemental analysis, FTIR, and single-crystal X-ray analysis. Complex C1 crystallizes as binuclear where two Cu (II) ions are bridged by four acetate ligands while C2 is a mononuclear complex with twisted octahedral geometry. Density functional theory (DFT) calculations revealed that electronic transitions originate from metal-ligand charge transfer and d - d transitions of metal ions. According to the results of UV–Vis and fluorescence titrations, C1 and C2 intercalate with DNA with the binding constants of 6.9 × 105 M−1 and 5.9 × 105 M−1, respectively. The in vitro cytotoxicity assays on four cancer cell lines (HeLa, HepG2, MCF-7 and A549) and a normal HUVEC cell line indicated higher anti-MCF-7 activity of C2 compared with cisplatin (IC 50 = 2.86 ± 0.08 μM vs. 9.07 ± 0.10 μM). Moreover, C2 had superior selectivity since IC 50 toward HUVEC cells was over 150 μM compared with 0.58 ± 0.05 μM for cisplatin. We concluded that the anti-MCF activity of mononuclear C2 complex is better than that of binuclear C1 and cisplatin. Therefore, C2 has been selected as a hit compound to develop novel non‑platinum anticancer agents through modification of coumarin-amide structure and variation of copper (II) salts. The anticancer activities, DNA interaction, and electron structure of Cu (II) complexes with coumarin-amide ligand (L)- C1 (Cu 2 L 2 (OAc) 4) and C2 (CuL 2 (NO 3) 2) were reported. C2 has been selected as a hit compound to develop novel non‑platinum anticancer agents because of its higher anti-MCF-7 activity and lower cytotoxicity than that of cisplatin. [Display omitted] • Two novel Cu (II) complexes (C1, C2) with coumarin-amide ligand were synthesized. • These complexes were characterized by single-crystal X-ray diffraction analysis. • The anti-MCF-7 activity of complex C2 is better than that of C1 and cisplatin. • Complexes C1 and C2 could effectively bind with DNA through intercalation mode. • DFT calculations of molecular orbitals and charge transfer were studied. [ABSTRACT FROM AUTHOR]

The local structure around the transition metal (TM) ions (Cr 3+ and Mn 2+ ) centers in K 2 MgF 4 , namely tetragonal (TE) center I, monoclinic (MO) center II and orthorhombic (OR) centers III, have been explored by semi-empirical calculations in the frame of superposition model (SPM). We proposed the most appropriate structural model for each center by matching the theoretically predicted zero-field splitting parameters (ZFSPs) with the experimental ones obtained by EPR spectroscopy. It is shown that the tetragonality of MgF 6 octahedra increases with the substitution of both Cr 3+ and Mn 2+ for Mg 2+ sites as well as with a rather higher value for the latter one. A tilt angle of 12.51° is found for MO Cr 3+ center, which is comparatively small, as compared to the other A 2 BF 4 crystals such as K 2 ZnF 4 and Tl 2 ZnF 4 . Almost three times larger relaxation of intervening F-ligand than that of other equatorial F-ligands is also indicated for OR Cr 3+ center. [ABSTRACT FROM AUTHOR]

The synthesis, X-ray crystallographic structure, and water uptake measurements of the first coordination polymer made of a cyclodextrin and a transition metal ion (in this case, Cu2+) are shown. This coordination polymer is made by connecting paddle-wheel Cu2+ units through a γ-cyclodextrin functionalized with eight carboxylate groups, is stable in water, and shows selective water-induced reversible structural transformations. [ABSTRACT FROM AUTHOR]

In this paper an investigation into the effect of transition metal ion and selenate/fluorophosphate doping on the structures of Na 2 M(SO 4 ) 2 ·2H 2 O (M=transition metal) materials is reported. In agreement with previous reports, the monoclinic (Kröhnkite) structure is adopted for M=Mn, Fe, Co, Cu, while for the smallest first row divalent transition metal ion, M=Ni, the triclinic (Fairfieldite structure) is adopted. On selenate doping there is a changeover in structure from monoclinic to triclinic for M=Fe, Co, Cu, with the larger Fe 2+ system requiring the highest level of selenate to complete the changeover. Thus the results suggest that the relative stability of the two structure types is influenced by the relative size of the transition metal: oxoanion group, with the triclinic structure favoured for small transition metals/large oxoanions. The successful synthesis of fluorophosphate doped samples, Na 2 M(SO 4 ) 2−x (PO 3 F) x ·2H 2 O was also obtained for M=Fe, Co, Cu, with the results showing a changeover in structure from monoclinic to triclinic for M=Co, Cu for very low levels (x=0.1) of fluorophosphate. In the case of M=Fe, the successful synthesis of fluorophosphates samples was achieved for x≤0.3, although no change in cell symmetry was observed. Rather in this particular case, the X-ray diffraction patterns showed evidence for selective peak broadening, attributed to local disorder as a result of the fluorophosphate group disrupting the H-bonding network. Overall the work highlights how isovalent doping can be exploited to alter the structures of Na 2 M(SO 4 ) 2 ·2H 2 O systems. [ABSTRACT FROM AUTHOR]

Changes in structure and magnetic properties accompanying guest removal, inclusion, or exchange in two CN-bridged 2D networks of honeycomb topology: {[Ni(cyclam)]3[Fe(CN)6]2}n (1) and {[Ni(cyclam)]3[Cr(CN)6]2}n (2) (cyclam = 1,4,8,11-tetraazacyclotetradecane) were studied by PXRD and magnetic measurements. For each compound four pseudopolymorphic forms differing in structure and magnetic characteristics were identified: fully hydrated form stable in water, partly hydrated form stable in the air at ambient conditions, anhydrous form, and MeOH-modified form. All forms can be reversibly transformed into one another by several interconversion pathways, which fully correspond between Fe and Cr compounds. All forms of 1 and 2 are metamagnetic-like with varied Tc and critical field Hcr. For several forms, differently shaped magnetic hysteresis loops can be observed. For the partly hydrated and MeOH modified forms structure models are proposed on the basis of PXRD data. Correlations between structural features and magnetic properties are discussed. [ABSTRACT FROM AUTHOR]

Stacking interactions between two benzene molecules that coordinate transition metal ions within organometallic sandwich and half-sandwich compounds were investigated by performing Cambridge Structural Database (CSD) search and DFT-D calculations. Calculations of interaction energies revealed that stacking interactions between coordinating benzenes of sandwich (−3.69 kcal/mol) and half-sandwich compounds (−3.29 kcal/mol) are significantly stronger than the stacking interaction between noncoordinating benzenes (−2.73 kcal/mol). At large horizontal displacements (offset r = 5.0 Å), these sandwich∥sandwich interactions are remarkably strong (−3.03 kcal/mol), while half-sandwich∥half-sandwich interactions are significantly weaker (−1.27 kcal/mol). The results of calculations are in good agreement with the data in the crystal structures from the CSD, where 76% of sandwich∥sandwich contacts have large horizontal displacements, which is significantly more than 46% of half-sandwich∥half-sandwich contacts arranged in this fashion. The study provides valuable information about interactions of aromatic molecules relevant to crystal engineering, materials design, and molecular recognition. [ABSTRACT FROM AUTHOR]

A major environmental concern related to nuclear energy is wastewater contaminated with uranium, thus necessitating the development of pollutant-reducing materials with efficiency and effectiveness. Herein, highly selective mesoporous silicas functionalized with amine-bridged diacetamide ligands SBA-15-ABDMA were prepared. Different spectroscopy techniques were used to probe the chemical environment and reactivity of the chelating ligands before and after sorption. The results showed that the functionalized SBA-15-ABDMA had a strong affinity for uranium at low pH (pH = 3) with desirable sorption capacity (68.82 mg/g) and good reusability (> 5). It showed excellent separation performance with a high distribution coefficient (K d,U > 105 mL/g) and separation factors SF U/Ln > 1000 at a pH of 3.5 in the presence of lanthanide nuclides, alkaline earth metal and transition metal ions. In particular, SiO 2 spheres-ABDMA was used as a column material, which achieved excellent recovery of U(VI) (> 98%) and good reusability for samples of simulated mining and nuclear industries wastewater. XPS and crystallography studies clearly illustrated the tridentate coordination mode of U(VI)/PEABDMA and the mechanism and origin behind the high selectivity for U. [Display omitted] • U(VI) sorbents based on amine-bridged diacetamide-functionalized silica are presented. • High U(VI) sorption performance and selectivity are observed at low pH. • Separation of uranium from wastewater are achieved by chromatography. • Coordination mode and selectivity of U(VI) are illustrated by crystallography. [ABSTRACT FROM AUTHOR]

Two new 3d–4f heterometallic 1D chains of formulae {[Dy2M2L4(NO3)(H2O)3][Dy2M2L4(NO3)(CH3COO)(H2O)2]·NO3·12H2O·2C2H5OH}n [M = Ni (1); Co (2)] have been prepared using the multidentate ligand 2-{[(2-hydroxy-3-methoxyphenyl)methylidene]amino}benzoic acid (H2L), which has NO and OO′ chelating pockets that are able to selectively encapsulate LnIII and transition metal ions, respectively. Crystal structure analyses reveal that the two complexes are isostructural and display one-dimensional ladder-like double helical chain structures, in which the two single helical chains {[Dy2M2L4(NO3)(H2O)3]+} and {Dy2M2L4(NO3)(CH3COO)(H2O)2} (M = Ni(1), Co(2)) both run along the c-axis and have opposite chirality. Complexes 1 and 2 represent the first example of 3d–4f double-chain frameworks in which the compositions of the two individual chains are different. Variable temperature dc magnetic susceptibility studies reveal different strengths of ferromagnetic interactions between the magnetic centers in 1 and 2, which is mainly attributed to the different metal centers and finally results in the distinctive magnetic dynamic behaviors. [ABSTRACT FROM AUTHOR]

Two species trivalent transition metal ions, nonmagnetic Al 3+ , Bi 3+ and magnetic Cr 3+ , Mn 3+ substituted barium hexaferrite powders are synthesised via dynamic hydrothermal method then calcinated at different temperatures. Powder XRD patterns analysis and Rietveld refinement indicate magnetoplumbite-type crystalline phase. The crystallite size calculated using Scherer's formula varies from 153 to 248 nm as it is affected by the ionic radius of trivalent metal ions and calcination temperatures. The morphological features show agglomerations of spherical-shaped particles with an average size of 400 ± 50 nm for BaBiFe 11 O 19 and hexagonal-shaped particles 1–2 μm for the other substitutions. Magnetic studies show a ferromagnetic behaviour for all samples. The nonmagnetic Al 3+ , Bi 3+ substituted materials have lower saturation magnetization (Ms) and remanence (Mr) than the magnetic substitutions Cr 3+ , Mn 3+ . These results reveal that Ms and Mr are related to the magnetic moment of each metallic ion and its distribution in the lattice. For magnetic substitution, Ms of manganese substitution (61.10 emu/g) is found higher than that of chromium (60.33 emu/g) since Mn 3+ has a magnetic moment of 5μ B greater than Cr 3+ with 3μ B . Coercivity Hc and maximum energy product (BH) max determined from M−H loops exhibit an increasing trend with calcination temperature as they are related to the crystallite size. Hc and (BH) max of BaMnFe 11 O 19 are found maximum 0.426 T and 7.47 kJ m −3 , respectively. [ABSTRACT FROM AUTHOR]

By the low-gradient Čzochralski method, both undoped and copper ion activated LiMg(MoO) crystals are grown. The charge state and structural position of impurity copper ions are determined using EPR. Investigations of the luminescence properties reveal that luminescence with a maximum at λ = 520 nm is observed for LiMg(MoO) crystals. A decrease in the temperature increases the intensity of this luminescence. It is found that the doping of LiMg(MoO) crystals with copper ions also increases the luminescence intensity with a maximum at λ = 520 nm. It is supposed that cation vacancies, which provide the charge compensation when copper ions substitute for lithium ions, are responsible for the luminescence. [ABSTRACT FROM AUTHOR]

Four m -methylbenzoate (mb)-bridged heterometallic complexes, [DyM(H 2 O)(phen)(mb) 5 ] (phen = 1,10-phenanthroline, M = Ni ( 1 ), Fe ( 2 ), Cu ( 3 ), and Zn( 4 )), were solvothermally synthesized by varying different transition metal ions, and structurally and magnetically characterized. Structural analyses reveal that all the four samples are crystallographically isostructural, exhibiting triple carboxylate-bridged heterometallic binuclear structures with chelating phen molecule as terminus. Resulting from different magnetic nature of the transition metal ions, metamagnetic and weak antiferromagnetic interactions are respectively mediated between Dy III –Ni II and Dy III –Fe II ions by bidentate bridging carboxylate moiety. By contrast, strong ferromagnetic coupling is observed between Dy III –Cu II . More interestingly, the former two complexes display field-induced single-molecule magnetic behavior with the anisotropy barriers of 20 and 17 K, while 3 show frequency-dependent ac response by quantum tunneling. Thus, the combined dc and ac magnetic results from the simple binuclear model afford significant information for the heterometallic 3 d –4 f SMMs. [ABSTRACT FROM AUTHOR]

The reactions of Zn(II), Mn(II), and Ni(II) acetates with 1-picolinoyl-4-phenyl-3-thiosemicarbazide (Hppts) yielded [Zn(ppts)2]·CHCl3(3), [Mn(ppts)2]·THF (4), and [Ni(ppts)2]·THF (5), respectively, but HgCl2gave a cyclized product N-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole-2-yl-amine (2). The treatment of Hppts with conc. H2SO4formed N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-yl-amine (1). Hppts is a nonfluorescent material, but3,4and the cyclized products 1,3,4-oxadiazole/1,3,4-thiadiazole are fluorescent. The cyclized ligand N-phenyl-5-(pyridin-2-yl)-1,3,4-thiadiazole-2-amine (1) formed [Zn(2-Hppt)2(OAc)2] (6) and [Cd2(2-Hppt)2(OAc)2(μ-OAc)2] (7) in which Cd(II) has a binuclear acetate-bridged seven coordinate pentagonal bipyramidal geometry. Complex7is also a fluorescent material with maximum emission at 425 nm at an excitation wavelength of 254 nm. [ABSTRACT FROM PUBLISHER]

Many living organisms transform inorganic atoms into highly ordered crystalline materials. An elegant example of such biomineralization processes is the production of nano-scale magnetic crystals in magnetotactic bacteria. Previous studies implicated the involvement of two putative serine proteases, MamE and MamO, during the early stages of magnetite formation in Magnetospirillum magneticum AMB-1. Here, using genetic analysis and X-ray crystallography, we show that MamO has a degenerate active site, rendering it incapable of protease activity. Instead, MamO promotes magnetosome formation through two genetically distinct, noncatalytic activities: activation of MamE-dependent proteolysis of biomineralization factors and direct binding to transition metal ions. By solving the structure of the protease domain bound to a metal ion, we identify a surface-exposed di-histidine motif in MamO that contributes to metal binding and show that it is required to initiate biomineralization in vivo. Finally, we find that pseudoproteases are widespread in magnetotactic bacteria and that they have evolved independently in three separate taxa. Our results highlight the versatility of protein scaffolds in accommodating new biochemical activities and provide unprecedented insight into the earliest stages of biomineralization. [ABSTRACT FROM AUTHOR]

By changing the metal salts, two new transition metal-based coordination polymers (CPs), {[Co(DBA)(dmbpy)]·(DMF)·(HO)} ( 1), and {[(MeNH)Cd(DBA)]·(DMF)} ( 2) ((HDBA = 4,4′-methylenedibenzoic acid, dmbpy = 3,3′-dimethyl-4,4′-bipyridine) has been synthesized under the same reaction conditions (DMF and 130 °C) and were structurally characterized. Both compounds are synthesized using dual linkers (HDBA and dmbpy). 1 performs a 2-fold interpenetration 3D framework with pcu topology and is stable in aqueous solutions at pH range from 5 to 9, whereas 2 shows a 2D (4,4) network and is unstable in air. Furthermore, the magnetic and 3D luminescent properties of 1 and 2 are also investigated, respectively. The results suggest that metal salts influence on the final resulting CPs and the introduction of water repellent functional groups within the structure can largely enhance the hydrophobic properties of CPs. [ABSTRACT FROM AUTHOR]

The compounds (Hbipy) 2 [Co(bipy) 2 (H 2 O) 4 ] 2 (CoW 12 O 40 )·2bipy·7H 2 O ( 1 ) and [Ni 2 (Hbipy) 2 (bipy)(H 2 O) 4 (H 2 W 12 O 40 )]·5H 2 O ( 2 ) (bipy = 4,4-bipyridine) were synthesized hydrothermally and characterized by elemental analysis, IR spectroscopy, TG analyses, solid ultraviolet diffuse spectroscopy and single crystal X-ray diffraction method. In 1 the complex ions, [Co(bipy) 2 (H 2 O) 4 ] 2+ , construct a supramolecular layer through π-π stacking interaction. The heteropolyanions with central Co atom and supramolecular layers are linked by hydrogen bonds. In 2 a 2D structure is formed from metatungstate anions and binuclear Ni-bipy complexes through the coordination of metatungstate anions and bipy to Ni ions. Between the layers and bipyridine molecules are the hydrogen bond interactions. The formation of 1 and 2 shows that the solution acidity and metal ions influence greatly the structure of the compounds. Solid ultraviolet diffusion results indicate that the compounds 1 and 2 are potential semiconductor materials. In 1 and 2 there exists a weak antiferromagnetic interaction. [ABSTRACT FROM AUTHOR]

The first neutral coordination complex of adenosine-5′-diphosphate (ADP) with transition metal Cu(II) ion, [Cu(phen)(H 2 ADP)(NO 3 )]·H 2 O ( ADP–Cu ) (ADP = adenosine-5′-diphosphate, phen = 1, 10-phenanthroline monohydrate) has been synthesized and investigated by X-ray single-crystal diffraction method. Based on its crystal structure and supramolecular assembly analysis, the molecular and supramolecular chirality of ADP–Cu was studied comprehensively by liquid- and solid-state circular dichroism (CD) spectroscopy. It is the first example of the study about the chirality and supramolecular chirality for polyphosphate nucleotide coordination complex. [ABSTRACT FROM AUTHOR]

Interest in perovskites evenly spans Materials Science and Geophysics. Due to their inimitably lattice flexibility enabling small as well as large ions to be accommodated, perovskites have become a base structure for new technological applications. Understanding the mechanisms governing their evolution at non-ambient conditions (such as high-pressure and high-temperature) is fundamentally important both for devising functional materials and in order to provide the most reliable possible deep-Earth model. With particular attention being paid to the chemical nature of the constituent ions, a suite of orthorhombic perovskites has been selected and contrasted using several parameterizations and models. A new perspective on the pressure-induced distortion of orthorhombic perovskite structures has enabled their compressional behaviour to be redefined. [ABSTRACT FROM AUTHOR]