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The rational design of 2D polyoxometalate-based metal-organic framework (POMOF) nanosheets on a conductive substrate as a self-supporting electrode is highly attractive but a great challenge. Herein is the first demonstration of POMOF nanopillar arrays consisting of 2D nanosheets as a self-supported electrode for the hydrogen evolution reaction (HER) in acidic conditions. Single-crystal X-ray analysis reveal that our as-prepared 2D [Co

A warm persistent luminescence (PersL) material SrBaZn2Ga2O7:Bi3+ was prepared using the conventional high-temperature solid-phase reaction method. We first investigated the PersL properties of SrBaZn2Ga2O7:Bi3+ in detail via PersL spectra, PersL excitation spectrum, PersL decay curves, and thermoluminescence (TL) spectra. The highlight of this study is that in addition to the 254 nm light source, the low-energy light source of 365 nm and sunlight can effectively excite electrons and charge traps, resulting in preferable orange PersL performance. The PersL decay time of the representative sample can last for 960 s after excitation by a 365 nm light source and 900 s after excitation by simulated sunlight. Meanwhile, the PersL color can be regulated by changing the excitation wavelength. In order to explain the infrequent PersL phenomena after different light source excitations, we recorded a series of TL spectra as a function of different light sources, different charging times, and different decay times to reveal the distribution of traps in the material and the influence of trap distribution on trapping and detrapping processes. This novel sunlight-activated orange PersL material is expected to promote the development of sunlight-activated PersL materials and expand potential applications in solar energy utilization and anticounterfeit marking.

Rational design of metal-organic frameworks (MOFs) into ultrathin two-dimensional (2D) nanosheets with controllable thickness is significantly attractive but is also a significant challenge. Herein, the authors report, for the first time, the synthesis of ultrathin 2D nickel-based MOF nanosheets with a thickness of only about 2 nm via a ligand-assisted controllable growth strategy, which cannot be acquired from the exfoliation of their bulky counterparts or the conventional hydrothermal method. The correlation between 2D nanosheets and crystal growth preference was demonstrated through a judicious choice of a specific [Ni(BIP)(

Two Ni-substituted polyoxometalates (NiSPs), [Ni6(Py)6(H2O)5(μ3-OH)3(PW9O34)]2·10H2O (1), [Ni7(Py)6(Im)(H2O)5O(WO4)(μ3-OH)3(H2PW9O34)]·3H2O (2) (Py = pyridine, Im = imidazole), were successfully hydrothermally synthesized. Compounds 1 and 2 have significantly different configurations by introducing different amounts of imidazole ligands. For compound 1, two malposed {Ni6(Py)6PW9} units that are face to face are bridged by two Ni-O-W bonds to constitute an isolated dimeric structure. Differently, the {Ni7(Py)6(Im)PW9}2 dimer in compound 2 connects with four adjacent dimers by four {WO4} groups in an interesting two-dimensional (2-D) arrangement. The magnetism of compounds 1 and 2 was studied, and magnetic test results demonstrated that both compounds have ferromagnetic interactions between the nickel centers. Meanwhile, the third-order nonlinear optical (NLO) measurements indicated that compound 1 can serve as potential nonlinear optical materials.

A series of V-substituted α-MnO2 (KxMn8-yVyO16·nH2O, y = 0, 0.2, 0.34, 0.75) samples were successfully synthesized without crystalline or amorphous impurities, as evidenced by X-ray diffraction (XRD) and Raman spectroscopy. Transmission electron microscopy (TEM) revealed a morphological evolution from nanorods to nanoplatelets as V-substitution increased, while electron-energy loss spectroscopy (EELS) confirmed uniform distribution of vanadium within the materials. Rietveld refinement of synchrotron XRD showed an increase in bond lengths and a larger range of bond angles with increasing V-substitution. X-ray absorption spectroscopy (XAS) of the as-prepared materials revealed the V valence to be >4+ and the Mn valence to decrease with increasing V content. Upon electrochemical lithiation, increasing amounts of V were found to preserve the Mn-Mnedge relationship at higher depths of discharge, indicating enhanced structural stability. Electrochemical testing showed the y = 0.75 V-substituted sample to deliver the highest capacity and capacity retention after 50 cycles. The experimental findings were consistent with the predictions of density functional theory (DFT), where the V centers impart structural stability to the manganese oxide framework upon lithiation. The enhanced electrochemistry of the y = 0.75 V-substituted sample is also attributed to its smaller crystallite size in the form of a nanoplatelet morphology, which promotes facile ion access via reduced Li-ion diffusion path lengths.

Luminescent copper(I) halide complexes with bi- and tridentate rigid ligands have gained wide research interests. In this paper, six tetracoordinate dinuclear copper(I) halide complexes, Cu2X2(ppda)2 [ppda = 2-[2-(dimethylamino)phenyl(phenyl)phosphino]-N,N-dimethylaniline, X = I (1), Br (2), Cl (3)] and Cu2X2(pfda)2 [pfda = 2-[2-(dimethylamino)-4-(trifluoromethyl)phenyl(phenyl)phosphino]-N,N-dimethyl-5-trifluoromethylaniline, X = I (4), Br (5), Cl (6)], were successfully prepared and systematically characterized on their structures and photophysical properties. Complexes 1-5 have a centrosymmetric form with a planar Cu2X2 unit, and complex 6 has a mirror symmetry form with a butterfly-shaped Cu2X2. Solid complexes 1, 4, and 5 emit delayed fluorescence at room temperature, intense blue to greenish yellow (λmax = 443-570 nm) light, and their peak wavelengths are located at 443-570 nm with microsecond lifetimes (τ = 0.4-19.2 μs, ΦPL = 0.05-0.48). Complexes 2, 3, and 6 show prompt fluorescence, very weak yellowish green to yellow (λmax = 534-595 nm) emission with peak wavelengths at 534-595 nm, and lifetimes in nanoseconds (τ = 4.4-9.3 ns, ΦPL < 0.0001). (Metal + halide) to ligand and intraligand charge transitions are the main origin of the emission of the complexes. Solution-processed, complex-4-based nondoped and doped devices emit yellow green light with CIE coordinated at (0.41, 0.51), a maximum EQE up to 0.17%, and luminance reaching 75.52 cd/m2.

How to incorporate chromophores into MOFs is a key for the development of multifunctional photoactive systems. The poor internalization by cancer cells and low efficiency of ROS generation hamper the potential clinic application of Ru-based molecular agents. In this work, a nanoscale Ru-doped metal-organic framework Hf-UiO-Ru (Hf-Ru) with framework-boosted photoactivities was prepared

Catalytic biomass conversions are sustainable processes to produce value-added fuels and chemicals but need stable catalysts that can tolerate harsh hydrothermal conditions. Herein, we report a hydrothermally stable catalyst by alloying Pt with a high-melting-point metal Nb. The Pt/Nb alloy catalysts are prepared by H2 reduction at a high temperature of 900 °C with a high-surface-area carbon black support, which can suppress metal sintering at high temperatures and thus lead to small-sized alloyed Pt/Nb particles of only 2.2 nm. Taking the advantages of surface acid property provided by the Nb sites and the size effect, the prepared C-supported small-sized Pt/Nb alloy catalysts exhibit attractive activities for the hydrogenation of levulinic acid into γ-valerolactone and the water-gas shift reaction. More significantly, benefiting from the inherent stability of high-melting-point Nb, the Pt/Nb alloy catalysts show much enhanced hydrothermal stability compared to commercial Pt/C and Ru/C catalysts.

Luminescent thermochromic materials with a dramatic shift of emission band under different temperatures are highly desirable in temperature sensing fields. However, the design of the synthesis of such compounds remains a great challenge. In this work, two new luminescent thermochromic silver iodides, (emIm)Ag3I4 (1) and (emIm)Ag2I3 (2) (emIm = 1-ethyl-3-methyl imidazole), have been synthesized under solvothermal conditions. Compound 1 features a [Ag3I4]- anionic layer, while compound 2 possesses an infinite [Ag2I3]- chain structure, both of which are charge balanced by emIm+ cations. Particularly, they display luminescent thermochromism with a significant wavelength shift of emission maximum with temperature change. They represent rare examples of infinite layered or chain silver iodides that show luminescent thermochromism. Furthermore, the results indicate that compounds 1 and 2 are promising wavelength-dependent luminescent thermometers.

A series of tunnel structured V-substituted silver hollandite (Ag1.2VxMn8-xO16, x = 0-1.4) samples is prepared and characterized through a combination of synchrotron X-ray diffraction (XRD), synchrotron X-ray absorption spectroscopy (XAS), laboratory Raman spectroscopy, and electron microscopy measurements. The oxidation states of the individual transition metals are characterized using V and Mn K-edge XAS data indicating the vanadium centers exist as V5+, and the Mn oxidation state decreases with increased V substitution to balance the charge. Scanning transmission electron microscopy of reduced materials shows reduction-displacement of silver metal at high levels of lithiation. In lithium batteries, the V-substituted tunneled manganese oxide materials reveal previously unseen reversible nonaqueous Ag electrochemistry and exhibit up to 2.5× higher Li storage capacity relative to their unsubstituted counterparts. The highest capacity was observed for the Ag1.2(V0.8Mn7.2)O16·0.8H2O material with an intermediate level of V substitution, likely due to a combination of the atomic composition, the morphology of the particle, and the homogeneous distribution of the active material within the electrode structure where factors over multiple length scales contribute to the electrochemistry.

It remains a great challenge to introduce large and efficient homogeneous asymmetric catalysts into MOFs and other microporous materials as well as retain their degrees of freedom. Herein, a new heterogeneous strategy of homogeneous chiral catalysts is proposed, that is, to construct a yolk-shell MOFs-confined, large-size, and highly efficient homogeneous chiral catalyst, which can be used as a nanoreactor for asymmetric catalytic reactions.

A new series of axially chiral binuclear Pt(II) complexes with bridging ligands of binaphthalenes and octahydro-binaphthalenes and auxiliary ligands of β-diketones were designed and prepared. These complexes, identified by spectral and electrochemical methods and single-crystal X-ray diffraction, emit an orange-red phosphorescence with a quantum yield up to 21% and 70% in solution and solid, respectively, due to the effect of steric hindrance from bridging ligands and the 2,3-position extension of chiral axis planes. They can be used as emitters in solution-processed organic light-emitting diodes to achieve luminance efficiency, asymmetry factor, and external quantum efficiency up to 5.4 cd A-1, 3.0 × 10-3, and 3.1%, respectively. Moreover, the essential relationships between their chemical structures and luminescence quantum efficiency and asymmetry factor are discussed, which affords explicit insights for designing circularly polarized luminescent materials and devices.

A series of V-substituted α-MnO

With the rapid development of the nuclear industry, how to deal with radioactive iodine waste in a timely and effective manner has become an important issue to be solved urgently. Herein, the defect-engineering strategy has been applied to develop a metal-organic framework (MOF)-based solid adsorbent by using the classical UiO-type Hf-UiO-66 as an example. After simple acid treatment, the produced defect-containing Hf-UiO-66 (DHUN) not only retains its topological structure, high crystallization, and regular shape but also shows a great increase in the Brunauer-Emmett-Teller value and pore size in comparison with the original Hf-UiO (HUN). These formed defects within DHUN have been demonstrated to be important for the great enhancement of the iodine capture and following application in computed tomography imaging in vitro. This present work gives a new insight into the control and formation of defect sites, and this simple and efficient defect-engineering strategy also shows great promise for the development of novel solid adsorbents and other functional MOF materials.

Luminescent copper(I) halide complexes with bi- and tridentate rigid ligands have gained wide research interests. In this paper, six tetracoordinate dinuclear copper(I) halide complexes, Cu

Controlling the chemical bonding of an active atom and carbon support is an effective strategy for enhancing the electrocatalytic activity of a metal-nitrogen/carbon catalyst. Herein, highly dispersed Co atoms are successfully prepared by using an ultrathin g-C3N4@carbon sphere as the support, and subsequently the well-defined Co-N and Co-O bonds on the atomic level are controllably constructed by adjusting the calcination atmosphere. Results show that highly dispersed Co with Co-O and Co-N bonds exhibits excellent oxygen evolution reaction performance in alkaline media at low and high overpotentials, respectively, and outperform most single-atom catalysts reported to date. DFT calculation, coupled with high-angle annular dark-field scanning transmission electron microscopy and X-ray photoelectron spectrometry techniques, reveals that the high activities mainly originate from the precise O-Co-N and N-Co-N coordination in the ultrathin g-C3N4@carbon sphere support. The enhancement mechanism of chemical bonding provides guidance for the atomic exploration and design of electrocatalysts.

In recent years, although low-dimensional hybrid lead halides have received great attention due to the fascinating photoluminescent (PL) properties, the research is still on the early stage and only limited phases have been explored and characterized. Here, by introducing heterometals as mixed structural compositions and optical activity centers, we prepared a series of low-dimensional hybrid heterometallic halides, namely as, [(Me)-DABCO]

The present work reports preparation of 3D composites of reduced graphene oxide (RGO) with coral-like LiFePO4 particles in two steps, which involves the fabrication of LiFePO4 particles by the solvothermal method and the subsequent preparation of RGO/coral-like LiFePO4 composites by the etching method. The microwave absorption properties of LiFePO4 particles, coral-like LiFePO4 particles, and the RGO/coral-like LiFePO4 composites were studied. Our results show that the as-prepared RGO/coral-like LiFePO4 composites exhibit significantly improved microwave absorption properties compared with the pure LiFePO4 particles and coral-like LiFePO4 particles. The RGO/coral-like LiFePO4 composite (S-60) possesses optimized reflection loss (RL) performance with an RL value of −61.4 dB and a broad effective absorption bandwidth of 4 GHz (from 11.36 to 14.88 GHz and 16.32 to 16.8 GHz) at the matching thickness of only 2.4 mm. This demonstrates that the RGO/coral-like LiFePO4 composites can be superior candidates for li...

Two organic-inorganic hybrid complexes, (CH3NH3)Na[Fe(CN)5NO]·H2O (1) and (CH3NH3)2[Fe(CN)5NO] (2), which exhibit stepwise dielectric switching as well as photo-induced structural transformation, are synthesized and examined. In these two compounds, the photo-responsive complex anions, [Fe(CN)5NO]2-, connected by Na+ through N-Na coordination bonds or CH3NH3+ through N···H-N hydrogen bonds, form two-dimensional structures. One organic cation, CH3NH3+, that resides in the intralaminar cavity and plays a role as a template, undergoes a temperature-controlled order-disorder structural phase transition. As the frozen-thawed state change of the polar organic cations modifies the polarizability of materials, stepwise dielectric switching is observed at the phase transition temperature. Furthermore, the photo-induced linkage isomerism of [Fe(CN)5NO]2- building block survives in the new compounds at the low-temperature range, which is verified by variable-temperature IR spectra after photo-irradiation. The coexistence of switchable dielectric properties and photo-induced structural variation suggests multiple optical-electric roles of the present materials.

A series of tunnel structured V-substituted silver hollandite (Ag

Time-resolved transient absorption spectroscopy and computational analysis of D-π-A complexes comprising Fe

The well-known idea of “structure determines properties” can be understood profoundly in the case of hexagonal zinc dicyanometalate. Using density functional theory (DFT) calculations, we show the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) properties of Zn[Au(CN)2]2. The temperature dependence of phonon frequencies within the quasi-harmonic approximation (QHA) is investigated. The abnormal phonon hardening (frequency increase on heating) is detected in the ranges of 0–225, 320–345, and 410–430 cm–1, which can be indicative of the unusual physical properties of Zn[Au(CN)2]2. Due to the significance of low-energy phonon frequencies in Zn[Au(CN)2]2, in this work, the corresponding vibrational mode of the lowest-frequency optical phonon at the zone center is analyzed. The specific topology of a springlike framework that will produce the effects of a compressed spring on heating and an extended spring under hydrostatic pressure is identified and leads to the coexistence...

The development of new visible light-driven photocatalysts based on semiconducting materials remains a greatly interesting and challenging task for the purpose of solving the energy crisis and environmental issues. By using photosensitive [(Me)2-2,2′-bipy]2+ (1,1′-dimethyl-2,2′-bipyridinium) cation as template, we synthesized one new type of inorganic−organic hybrid cuprous and silver halogenides of [(Me)2-2,2′-bipy]M8X10 (M = Cu, Ag, X = Br, I). The compounds feature a three-dimensional anionic [M8X10]2– network composed of a one-dimensional [M8X12] chain based on MX4 tetrahedral units. The photosensitization of organic cationic templates results in narrow band gaps of hybrid compounds (1.66–2.06 eV), which feature stable visible light-driven photodegradation activities for organic pollutants. A detailed study of the photocatalytic mechanism, including the photoelectric response, photoluminescence spectra, and theoretical calculations, shows that the organic cationic template effectively inhibits the rec...

Transition-metal complexes, ruthenium(II) and iridium(III) complexes in particular, with fascinating triplet emissions are rapidly emerging as important phosphorescent dyes for application in the sensing and imaging of biological makers in live cells and organisms. In this contribution, two red-emitting transition-metal complexes, [Ru(bpy)2(DA-phen)](PF6)2 and [Ir(ppy)2(DA-phen)](PF6) (bpy = 2,2′-bipyridine, DA-phen = 4,5-diamino-1,10-phenanthroline, and ppy = 2-phenylpyridine), were designed and synthesized as phosphorescent probes for the highly sensitive and selective detection of methylglyoxal (MGO), an essential biomarker in the etiopathogenesis of several diseases. Both probes showed weak emissions in aqueous media because of the existence of an effective photoinduced-electron-transfer process, while their emissions could be remarkably enhanced upon the addition of MGO. The photophysical and electrochemical properties, as well as phosphorescent responses of the probes toward MGO, were examined. The ...

Controlling the chemical bonding of an active atom and carbon support is an effective strategy for enhancing the electrocatalytic activity of a metal-nitrogen/carbon catalyst. Herein, highly dispersed Co atoms are successfully prepared by using an ultrathin g-C

The present work reports preparation of 3D composites of reduced graphene oxide (RGO) with coral-like LiFePO

An SOD-type metalloaluminophosphate molecular sieve (denoted as SOD-Mn) was ionothermally synthesized by introducing manganese(II) cations into the reaction mixture via MnO-acid or MnO2-reductant reactions. Composition and structure analyses results show that two kinds of manganese(II) cations exist in the SOD-Mn structure. Part of the manganese(II) cations isomorphously substitute the framework aluminum(III) with a substitution degree of ∼30%. The rest of the manganese(II) cations occupy a fraction of the sod cages in their hydrated forms. A comprehensive investigation of the synthesis parameters, crystal sizes, and crystallization kinetics indicates that the in situ released hydrated manganese(II) cations direct the formation of SOD-Mn. Such structure-directing effect may be inhibited by both the fluorination of manganese(II) cations and the water accumulation during crystallization. In the fluoride anion-containing reaction mixture with a low ionic liquid content, the crystallization process is strongly suppressed, and large SOD-Mn single crystals of over 200 μm in size are yielded. SOD-Mn is free from organics and shows improved thermal stability compared with metalloaluminophosphates synthesized by using organic structure-directing agents.

The well-known idea of "structure determines properties" can be understood profoundly in the case of hexagonal zinc dicyanometalate. Using density functional theory (DFT) calculations, we show the uniaxial negative thermal expansion (NTE) and negative linear compressibility (NLC) properties of Zn[Au(CN)

The self-assembly behavior of a tritopic 2,2':6',2″-terpyridine (tpy) ligand with Cd(II), Zn(II), and Fe(II) has been exploited herein to generate a series of tetrameric and hexameric macrocycles. The main advantage of using such transition metals with an octahedral coordination geometry is their distinct coordination abilities (e.g., binding strength and reversibility). With the same ligand, this study reveals that the supramolecular structural variation between tetrameric and hexameric macrocycle architectures can be precisely controlled using different metal ions with the same coordination geometry. When Cd(II) was used, a tetrameric macrocycle was the only observed structure in the self-assembly, whereas Zn(II) and Fe(II) assembled a mixture of tetrameric and hexameric macrocycles. Because of the high stability of Fe(II) as the coordination center, we successfully isolated tetrameric and hexameric macrocycles using a regular column. In-depth characterization was carried out to establish the proposed structures, including multinuclear NMR (1H, 19F, and 13C) analysis, electrospray ionization mass spectrometry, and 2D ion-mobility mass spectrometry.

Two Cu(I) cluster based coordination polymers, [CuI(cis-bpype)]·CH3CN (1) and [Cu4I4(cis-bpype)3(trans-bpype)]·3DMF (2), have been synthesized from cis- and trans-1,2-bis(4-(pyridin-2-yl)phenyl)ethane (cis- and trans-bpype) ligands and {Cu4I4(PPh3)4} as starting materials. In compound 1, adjacent rhomboid-type {Cu2I2} units from the decomposition of {Cu4I4(PPh3)4} starting material connect by cis-bpype ligands to form a 1D framework. Compound 2 also has a 1D structure, but it has a {M2L3}-type coordinated cage constructed by three cis-bpype ligands and two {Cu4I4} secondary building units (SBU), and these coordination cages further link by trans-bpype to form the final frameworks. Upon cooling from 300 to 80 K, these Cu(I) cluster based coordination polymers exhibit interesting thermochromic behavior. In particular, compound 2 gives a chromic process from green luminescence at room temperature to red luminescence at 80 K and its corresponding CIE coordinates shift from green (0.34, 0.43) at 300 K to red (0.46, 0.42) at 80 K, respectively. This red shift of 124 nm (516 to 640 nm) is large enough to ensure a color change visible to the naked eye, which can be potentially utilized as a temperature sensor with a wide range.

The use of the N-heterocyclic carbene (NHC) ligands 1,3-bis(2',6'-diethylphenyl)-4,5-(CH2)4-imidazol-2-ylidene (cyIDep), 1,3-bis(2',6'-diethylphenyl)-imidazolin-2-ylidene (sIDep), and its N-mesityl analogue sIMes enables the preparation of the two-coordinate homoleptic iron(I)-NHC complexes [(cyIDep)2Fe][BAr(F)4] (3, Ar(F) denoted for 3,5-di(trifluoromethyl)phenyl) and [(sIDep)2Fe][BAr(F)4] (4) and the T-shaped iron(I)-NHC complex [(sIMes)2Fe(THF)][BPh4] (5, THF = tetrahydrofuran). Complexes 3-5 were prepared via the sequential protocol of control reduction of iron(II) dihalides by KC8 in the presence of the corresponding NHC ligands followed by halide-abstraction with NaBAr4. Spectroscopic characterization, including single-crystal X-ray diffraction studies and (57)Fe Mössbauer spectroscopy, in combination with density functional theory calculations, suggest their high-spin nature. Solution property study (absorption spectroscopy and cyclic voltammetry) indicates that 3 and 5 keep their corresponding two- and three-coordinate nature in THF solution, and 4 might reversibly coordinate a THF molecule to form, presumably, the T-shaped species [(sIDep)2Fe(THF)][BAr(F)4]. The isolation of 3 and 4 demonstrates the accessibility of homoleptic two-coordinate iron(I)-NHC complexes.

The salt elimination reactions of (IPr2Me2)2FeCl2 (IPr2Me2 = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) with the corresponding aryl Grignard reagents afford [(IPr2Me2)2FeAr2] (Ar = Ph, 3; C6H4-p-Me, 4; C6H4-p-(t)Bu, 5; C6H3-3,5-(CF3)2, 6) in good yields. X-ray crystallographic studies revealed the presence of both tetrahedral and trans square planar isomers for 3 and 6 and the tetrahedral structures for 4 and 5. Magnetic susceptibility and (57)Fe Mössbauer spectrum measurements on the solid samples indicated the high-spin (S = 2) and intermediate-spin (S = 1) nature of the tetrahedral and square planar structures, respectively. Solution property studies, including solution magnetic susceptibility measurement, variable-temperature (1)H and (19)F NMR, and absorption spectroscopy, on 3-6, as well as an (57)Fe Mössbauer spectrum study on a frozen tetrahydrofuran solution of tetrahedral [(IPr2Me2)2(57)FePh2] suggest the coexistence of tetrahedral and trans square planar structures in solution phase. Density functional theory calculations on (IPr2Me2)2FePh2 disclosed that the tetrahedral and trans square planar isomers are close in energy and that the geometry isomerization can occur by spin-change-coupled geometric transformation on four-coordinate iron(II) center.

The development of new visible light-driven photocatalysts based on semiconducting materials remains a greatly interesting and challenging task for the purpose of solving the energy crisis and environmental issues. By using photosensitive [(Me)

Mononuclear Ru-based water oxidation catalysts containing anionic ancillary ligands have shown promising catalytic efficiency and intriguing properties. However, their insolubility in water restricts a detailed mechanism investigation. In order to overcome this disadvantage, complexes [Ru(II)(bpc)(bpy)OH2](+) (1(+), bpc = 2,2'-bipyridine-6-carboxylate, bpy = 2,2'-bipyridine) and [Ru(II)(bpc)(pic)3](+) (2(+), pic = 4-picoline) were prepared and fully characterized, which features an anionic tridentate ligand and has enough solubility for spectroscopic study in water. Using Ce(IV) as an electron acceptor, both complexes are able to catalyze O2-evolving reaction with an impressive rate constant. On the basis of the electrochemical and kinetic studies, a water nucleophilic attack pathway was proposed as the dominant catalytic cycle of the catalytic water oxidation by 1(+), within which several intermediates were detected by MS. Meanwhile, an auxiliary pathway that is related to the concentration of Ce(IV) was also revealed. The effect of anionic ligand regarding catalytic water oxidation was discussed explicitly in comparison with previously reported mononuclear Ru catalysts carrying neutral tridentate ligands, for example, 2,2':6',2″-terpyridine (tpy). When 2(+) was oxidized to the trivalent state, one of its picoline ligands dissociated from the Ru center. The rate constant of picoline dissociation was evaluated from time-resolved UV-vis spectra.

A new bridging ligand 1,3,6,8-tetrakis(1-butyl-1H-1,2,3-triazol-4-yl)pyrene (ttapyr) was designed and synthesized by "click" chemistry. This ligand was used to construct a linear dimetallic biscyclometalated Ru(II) complex [(tpy)Ru(ttapyr)Ru(tpy)](2+) and a monometallic complex [(tpy)Ru(ttapyr)](+), where tpy is 2,2':6',2″-terpyridine. The electronic properties of these complexes were studied and compared by electrochemical and spectroscopic methods with the aid of DFT calculations. One-electron oxidation of [(tpy)Ru(ttapyr)Ru(tpy)](2+) with cerium ammonium nitrate produced a mixed-valent complex [(tpy)Ru(ttapyr)Ru(tpy)](3+). The intramolecular electronic coupling between individual metal centers was quantified by the intervalence charge transfer transition analysis. Mixed-valent complex [(tpy)Ru(ttapyr)Ru(tpy)](3+) exhibits a metal-centered rhombic EPR signal at 77 K with an average g factor of 2.203.

A series of novel Pd(II) and Pt(II) complexes, [PdL(2)Cl(2)]·DMF (1), [Pd(2)(L-H)(2)(bpy)Cl(2)]·(H(2)O)(2)·DMF (2), [Pd(2)(L-H)(2)(phen)Cl(2)]·2H(2)O (3), [PtL(2)Cl(2)]·H(2)O (4), [Pt(2)(L-H)(2)(bpy)Cl(2)]·2H(2)O (5), and [Pt(2)(L-H)(2)(phen)Cl(2)]·H(2)O (6), where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, and L = 1,3-benzothiazol-2-amine, have been synthesized and characterized. The competitive binding of the complexes to DNA has been investigated by fluorescence spectroscopy. The values of the apparent DNA binding constant, calculated from fluorescence spectral studies, were 3.8 × 10(6) (K(app)(4)), 2.9 × 10(6) (K(app)(1)), 2.4 × 10(6) (K(app)(6)), 2.0 × 10(6) (K(app)(5)), 1.2 × 10(6) (K(app)(3)), and 6.9 × 10(5) (K(app)(2)). The binding parameters for the fluorescence Scatchard plot were also determined. On the basis of the data obtained, it indicates that the six complexes bind to DNA with different binding affinities in the relative order 416532. Viscosity studies carried out on the interaction of complexes with Fish Sperm DNA (FS-DNA) suggested that all complexes bind by intercalation. Gel electrophoresis assay demonstrates that all the complexes can cleave the pBR 322 plasmid DNA and bind to DNA in a similar mode. The cytotoxic activity of the complexes has been also tested against four different cancer cell lines. The results show that all complexes have activity against KB, AGZY-83a, Hep-G2, and HeLa cells. In general, the Pt(II) complexes were found to be more effective than the isostructural Pd(II) complexes. The mononuclear complexes exhibited excellent activity in comparison with the dinuclear complexes in these four cell lines. Moreover, on the KB cell line (the human oral epithelial carcinoma), the observed result seems quite encouraging for the six complexes with IC(50) values ranging from 1.5 to 8.6 μM. Furthermore, apoptosis assay with hematoxylin-eosin staining shows treatment with the six complexes results in morphological changes of KB cells. The results induce apoptosis in KB cells.

Three new iron aluminum phosphates |(C(2)H(10)N(2))(4)|[Fe(8 - x)Al(x)F(x)(H(2)O)(2 - x)(PO(4))(8)]·2H(2)O (χ = 1.64, 1.33, 0.80) with ACO-zeotype structures denoted as FeAPO-CJ66(a), FeAPO-CJ66(b), and FeAPO-CJ66(c), respectively, have been synthesized in the fluoride ion system. Their framework structures are made of double 4-ring (D4R) building units formed by the alternating connection of Fe(Al)O(4)F(O) trigonal bipyramids and PO(4) tetrahedra, which possess 3D intersecting 8-ring channels running along the [001], [010], and [100] directions. Fluoride ions or water molecules reside in the center of D4Rs, and diprotonated ethylenediamine cations and water molecules are occluded in the free space of channels to stabilize the whole structure. Notably, the Al/Fe ratios in the frameworks can be effectively controlled from 1/3.9 to 1/5.0 to 1/9.0 by adjusting the amounts of phosphoric acid and hydrofluoric acid added to the initial reaction mixture. Mössbauer and magnetic measurements show that the Fe ions in the compounds are bivalent and undergo antiferromagnetic ordering at room temperature.