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Building metal-organic frameworks (MOFs) covalently modified by onium halides is a promising approach to develop efficient MOF-based heterogeneous catalysts for the cycloaddition of CO

Metal-organic frameworks (MOFs) provide an ideal platform for loading various guests owing to their available space, and can be developed as a class of multifunctional materials. Herein, we cover the design and synthesis of two kinds of exchanged frameworks with multifunctional applications based on H

Two tetra-nuclear Yb

In the present work, a new 3D metal-organic framework (MOF) has been synthesized and characterized. The MOF exhibits good chemical stability in aqueous solutions with the pH scale ranging from 3 to 11. Interestingly, the MOF shows high catalytic activities for the degradation of azo dyes (MO, CR and CBR) under visible light without H2O2. The Ea values of the MOF for MO, CR and CBR degradation are obtained to be 23.49, 52.68 and 15.19 kJ mol-1, respectively. In addition, the MOF can be reused in the catalytic process without the catalytic activity decreasing obviously.

We synthesized a novel MOF with an sqc1575 topology as an ideal host matrix that exhibits luminescence energy transfer with polycyclic aromatic hydrocarbons (PAHs). What's more, the PAHs@MOF composites display an interesting quenching behavior in the presence of the electron donor triethanolamine (TEOA). We report for the first time that the well-defined porosity of a luminescent MOF enables it to serve as a host matrix for encapsulating chromophoric PAH molecules to modulate luminescence properties, and further exploit its reductive quenching properties by using a photocatalytic sacrificial electron donor.

Two new cucurbit[6]uril (CB[6])-based metal-organic rotaxane networks (MORNs) were successfully obtained by tuning the coordination sphere of metal copper clusters. Compounds 1 and 2 exhibited relatively high proton conductivity at 85 °C and 97% relative humidity (RH), providing great promise for fuel cell electrolyte materials.

Two Ni/Co-substituted sandwich-type germanomolybdates, {[M

A novel AIPE-active neutral Ir(III) complex has been synthesized for rapid and reversible phosphorescent sensing of acid–base vapours due to the reversible protonation and deprotonation process occurring on functional Schiff base ligands.

We report an unprecedented {CuII14TeIV10} core containing the novel μ,μ-/μ6-TeIVO32- mode and TeIVO44- embedded within a 36-tungsto-4-silicate POT shell, which constitutes the first example of a tellurous copper cluster in POMs. The structure-stabilizing and templating effects of tellurite anions are crucial for this assembly. Moreover, its visible light-driven catalytic H2 evolution activity and related quenching mechanism are demonstrated, and extensive stability studies are presented.

Electrochemical deposition is an environment-friendly method for functional film fabrication, benefiting from the facile tuning of structure and properties of the film. Metal–organic frameworks (MOFs) play a significant role in the field of energy sources because of their porous nature, large specific surface area and metal ion binding sites. However, the application of such materials is limited by their inherent insulator-like characteristics and poor electrical conductivity. In this study, we designed and fabricated a composite material comprising metal–organic framework/polypyrrole as the positive electrode of a supercapacitor via smear and electrodeposition methods. Electrochemical properties of the electrode materials were studied through galvanostatic charge/discharge (GCD) and cyclic voltammetry (CV) tests. The positive electrode has an excellent specific capacitance of 284.3 F g−1 (180.7 mF cm−2) with 1 mA cm−2 current density. Furthermore, this material as a positive electrode shows high cycling stability after 40 000 cycles (100.7% capacitance retention). This strategy can be extended to fabricate other MOFs and MOFs/conducting polymers composite electrodes for supercapacitors.

Two functionalized polyoxovanadate-based metal–organic polyhedra with heterocube formations are synthesized under solvothermal conditions. The structures of VMOP-18 and VMOP-19 display similar cuboctahedral geometries when the polyoxovanadate {V6O6(OCH3)9X(COO)3}n− (X = VO4, n = 1; SO4, n = 2) building units and organic ligands are considered as triangular faces of the polyhedra. Each cuboctahedron was surrounded by eight neighbouring cuboctahedra via strong C–H⋯π interactions, leading to a 3D open supramolecular structure. Furthermore, the absorption ability toward the ionic dyes of VMOP-18 was investigated. Only cationic dyes can be absorbed into the cavity of VMOP-18, which indicates that the cationic dye absorption process is an ion-exchange process.

We utilise the dual synthesis strategy in terms of bimetallic inorganic building blocks and sulfur containing organic ligand. A novel sulfur-containing bimetallic metal organic framework (Fe2Co-TPDC) with two types of 4-fold meso-helical structures has been successfully synthesized. Benefitting from the uniform distribution of active sulfur sites and the structural stability of the mixed-metallic method, Fe2Co-TPDC can efficiently prevent a shuttle behavior of sulfur and endow a commendable specific capacity. As far as we know, this is the first time that a sulfur-containing bimetallic crystalline MOF with helical structure and prominent specific capacity and remarkable cycling stability has served as an electrode material for LIBs.

A new triazine-based covalent organic polymer (named COP-NT), which showed high catalytic activities for the degradation of acidic and basic dyes, is synthesized. Its structure characteristics were fully investigated, which featured large specific surface area, homogeneous porosity, strong visible light absorption, excellent thermal stability and semiconductor performance. The as-prepared COP-NT exhibits good chemical stability both in acidic and alkaline aqueous solutions, which could be used as an efficient photocatalyst for the degradation of methyl orange (MO), rhodamine B (RhB) and methylene blue (MB). The Ea values for the degradation of MO, RhB or MB are 9.40 kJ mol-1, 30.94 kJ mol-1 or 17.54 kJ mol-1, respectively. Furthermore, COP-NT showed excellent reusability in degrading all the above dyes without obvious performance decay.

Two dimethyltin-functionalized selenotungstates have been obtained: K

In this paper, a sandwich type of polyoxophosphotungstate K

Two novel mixed-addenda Nb/W polyoxometalates are successfully fabricated, and investigated as anode materials for lithium-ion batteries. For the Cs

An unprecedented polytantalotungstate (POTT), Cs12.5K4.5H[Ta12Si4W37O158]·25H2O (1), based on the {SiW9Ta3O40}7− cluster was hydrothermally synthesized. A photocatalytic study revealed that 1 exhibits significant photocatalytic water splitting activity.

The crystal structure of Cd-MOF-74 was obtained for the first time that possesses high sensitivity for the detection of copper ions from water and simulated biological fluids based on changes in luminescent intensity. Furthermore, Cd-MOF-74 could selectively remove Cu2+ from simulated biological fluids that contain Mg2+, Co2+, Zn2+, Fe2+, Ni2+, Na+, and K+. The adsorption capacity of this adsorbent for copper ions reached 189.5 mg g-1 and it quickly adsorbed copper ions within 10 minutes under 10 ppm Cu2+ in the simulated biological system. XPS, PXRD, and gas adsorption measurements revealed that this high sensitivity and selectivity of Cd-MOF-74 resulted from the partial substitution of Cd2+ by Cu2+ in the framework. Although many MOF materials have been employed for sensor or selective adsorption of Cu2+, Cd-MOF-74 is the first example of MOFs showing both capabilities in simulated biological fluids, which represents a pioneering work that extends the applications of MOF materials in the biological field.

Two isostructural vanadium-based metal-organic polyhedra (denoted as VMOP-16 and VMOP-17) were synthesized by a solvothermal method, which are built from unprecedented {V

Assembly of cucurbit[6] and a {Cd2Ge8V12O48} cluster produced two rotaxane-shaped and polyrotaxane-shaped solids by changing the ratio of starting precursors in the system. The high oxygen density of the polyoxoanion surface provides active sites to extend a single rotaxane-shaped hybrid 1 to a 1D polyrotaxane-shaped hybrid 2. This construction strategy may afford an entirely new methodology for polyoxometalate-based hybrid chemistry.

An efficient turn-on fluorescent sensor for PO4(3-) has been developed by rationally designing an in situ-generated iron(iii) complex with a 1,8-naphthalene-based Schiff base unit. The sensor exhibits high sensitivity and selectivity in both solution and solid-state film, even in the presence of other phosphate anions such as HPO4(2-) and H2PO4(-).

A sulfur-free iridium(III) complex (pbi)2Ir(mtpy) (1) was successfully prepared and adopted as a Hg(II)-chemosensor with high selectivity and sensitivity. Multi-signaling responses towards Hg(II) ions were observed by UV-vis absorption, phosphorescence and electrochemistry measurements. With addition of Hg(II) ions, complex 1 presented quenched emission in its phosphorescence spectrum and the detection limit was as low as 2.5 × 10(-7) M. Additionally, its redox peak currents showed a broad linear relationship with the concentration of Hg(II) ions ranging from 0 to 500 μM, which was beneficial for the quantitative detection. Based on the (1)H NMR and ESI-MS analyses, the probing mechanism was tentatively supposed to be the Hg(2+)-induced changes in the local environment of complex 1. Such a response process was useful for achieving simple and effective detection of Hg(II) ions as well as developing more chemosensors.

A di-vanadium-substituted Lindqvist-type polyoxometalate [Cu(C12H8N2)2]2[V2W4O19]·4H2O (1) was hydrothermally synthesized and characterized structurally by single crystal X-ray diffraction analysis. X-ray photoelectron spectroscopy and energy disperse spectroscopy tests further prove the existence of vanadium. Ultraviolet photoelectron spectroscopy and density functional theoretical studies indicate that the energy level of 1 matches well with the conduction band of the TiO2. Furthermore, considering the semiconductor-like nature of 1 and the introduction of transition metal element Cu synchronously extends the absorption to the visible region, which should also be beneficial to the photovoltaic device performance. 1-Doped TiO2 composites (denoted as 1@TiO2) have been successfully fabricated by a simple sol–gel method, and introduced into the dye-sensitized solar cells (DSSCs) as co-sensitizers in N719-sensitized photoanodes by mixing 1@TiO2 with P25 nanoparticles with different weight ratios to enhance the photoelectric conversion efficiency. The investigations show that the DSSC assembled with 1@TiO2/19P25 photoanode has the best performance and the overall improvement of the efficiency is 21.6% compared with pure P25. Furthermore, the electrochemical impedance spectroscopy and open-circuit voltage decay investigations show that the cosensitization of 1 and N719 can promote electron transfer and restrain charge recombinations in the DSSCs, resulting in a longer electron lifetime.

A novel 3D organic-inorganic hybrid framework constructed from tetra-Co(II)-substituted sandwich-type phosphotungstates with a rare 8-connected bcu topology is reported, which exhibited highly efficient photocatalysis activity under visible light and could be used for 5 cycles without any obvious decrease in activity.

A large lanthanide-containing tungstotellurites(iv) nanocluster Na18[Ce10Te8W88O298(OH)12(H2O)40]·54H2O () was synthesized by combining cerium linkers and TeO3(2-) heteroanion templates. The macroanion in consists of two identical [Te4W42O144(OH)6Ce4(H2O)13](14-) subunits and two triangle-shaped {W2O5Ce(H2O)7} linkers.

A thorough theoretical analysis was carried out on the sulfoxidation with H2O2 catalyzed by a tetranuclear peroxotungstate [SiO4{WO(O2)2}4](4-). The active species is the [SiO4{WO(O2)2}4(H2O2)](4-) (SiW4(H2O2)) complex rather than [SiO4{WO(O2)2}4](4-) (SiW4). The catalytic cycle consists of three elementary processes: oxygen transfer, sulfoxide dissociation, and catalyst regeneration. The oxygen transfer occurs from the peroxo oxygen atom O1 of SiW4(H2O2) to the sulfur center of dimethyl sulfide with a moderate Gibbs activation energy (ΔG°(‡)) of 17.1 kcal mol(-1). By comparing potential energy surfaces and condensed Fukui functions (ƒ(+)), the electrophilicity of the outer peroxo atoms in SiW4(H2O2) determines which oxygen transfers to the dimethyl sulfide. Then, the sulfoxide dissociation proceeds with a small ΔG°(‡) value of 2.3 kcal mol(-1) by elongation of the peroxo O1-O4 distance and elimination of the product dimethylsulfoxide. Finally, the catalyst regeneration is found to occur via two successive proton transfers from H2O2 to the oxygen atoms of peroxotungstates with the ΔG°(‡) values of 15.9 and 15.3 kcal mol(-1), which has been firstly examined in the present study. All of these steps occur easily with moderate ΔG°(‡) values, but the oxygen transfer is the rate-determining step of this catalytic reaction. In addition, the catalytic activity of peroxotungstates can be effectively tuned by changing the heteroatom X of [XO4{WO(O2)2}4(H2O2)](n-) in the order: Se(VI) ≈ S(VI)As(V) ≈ P(V)Si(IV).

Two novel pillared MOFs (metal organic frameworks) [Zn2(trz)2(tda)]·DMA CH3OH (1) and [Zn2(trz)2(bpdc)]·DMA (2) were obtained under solvothermal conditions. The resulting MOFs show similar structures but with different interlayer distances based on the different carboxylate ligands. 1 and 2 display a certain degree of framework stability in both acid/base solutions and water. The luminescence intensities of the activated phases 1a and 2a are sensitive to metal ions, particularly Fe(3+) and Cd(2+) ions. Furthermore, the luminescent properties of 1a and 2a well dispersed in different solvents have also been investigated systematically, which demonstrate distinct solvent-dependent luminescent spectra with emission intensities that are significantly quenched by acetone, nitrobenzene and trinitrotoluene.

A facile two-step strategy was developed to fabricate yellow fluorescent glutathione-Au nanoclusters/zeolitic imidazolate framework-8 nanoparticles (GSH-Au NCs/ZIF-8 NPs) and their derived Au/ZnO NPs, which exhibited visible light photocatalytic hydrogen evolution together with degradation of Rhodamine B (RhB).

Recently, the well-known phenalenyl radical π-dimer with its fascinating 2-electron/12-center (2e/12c) bond has attracted our attention. In this work, we designed two molecules, Li3O⋯C13H9 (1a) and BeF3⋯C13H9 (1b). Interestingly, owing to the inductive effect of superatoms, an electron is transferred from Li3O to phenalenyl in 1a, while an electron is transferred from phenalenyl to BeF3 in 1b. Further, we employed 1a and 1b as building blocks to assemble two novel molecules with 2e/12c bonds: Li3O⋯(C13H9)2⋯BeF3 (2a) and Li3O⋯(C13H9)2⋯BeF3 (2b). Remarkably, 2a and 2b with novel 2e/12c bonds exhibit a dramatic interlayer charge-transfer character, which results in a significant difference of dipole moments (Δμ: 2.6804 for 2a and 3.8019 Debye for 2b) between the ground state and the crucial excited state. As a result, the static first hyperpolarizabilities (β0: 5154 for 2a and 12 500 au for 2b) are considerably larger than the values of 347 for 1a and 328 au for 1b. It is our expectation that the results of the present work might provide beneficial information for further theoretical and experimental studies on the fascinating properties of molecules with interlayer charge-transfer character.

We report a rare all-thiol-stabilized [Ag28(S(t)Bu)23](5+) ({Ag28S23} for short) nanocluster with a "crab-like" shape in compound [Ag28(S(t)Bu)23](CF3COO)5·8CH3OH (1), which has been synthesized by the self-assembly of AgS(t)Bu with CF3COOH, Et3N and KBr/KI in methanol. The diffuse reflection spectrum and luminescence spectra of 1 were investigated.

A new 3D extended heteropoly blue Ba4[SiW(V)4W(VI)8O40]·H2O (1) composed of twelve-coordinated α-Keggin anions [SiW(V)4W(VI)8O40](8-) and eight-coordinated Ba sites {BaO8} has been hydrothermally synthesized and fully characterized by elemental analysis, IR spectroscopy, XPS, single crystal X-ray and X-ray powder (XRPD) diffraction. 1 represents the first inorganic 3D framework constructed from four-electron reduced α-Keggin anions linked by alkaline earth metals. The photocatalytic activity of 1 has been evaluated for rhodamine B (RhB) degradation. 1 exhibits excellent catalytic activity for the degradation of RhB in the presence of H2O2and the involvement of visible light makes a more complete degradation. The results of the current study suggest that multi-electron reduced polyoxometalates can catalyze efficient degradation of an organic dye with H2O2.

Recently, two isomeric thiophene-fused benzocarborane derivatives Tb1 and Tb2 with different locations of sulfur atoms, labeled as 1, 4 and 6, 9 of the thiophene were synthesized by Morisaki (Chem.–Eur. J., 2012, 18, 11251–11257) and Barrere (Macromolecules, 2009, 42, 2981–2987), respectively. In the present work, natural bond orbital (NBO) analysis shows that after doping one lithium atom into the isomeric structures Tb1 and Tb2, the electrons transfer to different regions in Tb1 and Tb2. For Tb1-Li, the transferred electrons mainly locate at S1, C2, C3, and S4, but for Tb2-Li, the transferred electrons mainly locate at C2, C3, C7, and C8. Significantly, the charge distribution is a crucial factor influencing the static first hyperpolarizabilities for Tb1-Li and Tb2-Li. Furthermore, the βtot value of Tb1-Li is 6222 au, which is about 160 times larger than that of Tb1 (39 au). However, the βtot value of Tb2-Li (498 au) is only about 5 times larger than that of the corresponding Tb2 (91 au). It is our expectation that this work could provide useful information for the development of nonlinear optical materials based on carboranes.

Two Anderson-type heteropolyanion-supported copper phenanthroline redox couples have been successfully introduced into dye-sensitized solar cells, which can significantly increase the short-circuit photocurrent, open-circuit voltage and the conversion efficiency by 2.2 times, 26.8% and 3.93 times respectively, compared to the pristine copper phenanthroline redox couple.

We report a novel type of organic-inorganic hybrid material with rare two-dimensional nonlinear optical (NLO) properties. The density functional theory (DFT) calculations combined with the finite-field (FF) method show that the designed molecules (6,9 organo-derivatives of B10H14) could carry the characteristic NLO properties of both organic and inorganic materials. Interestingly, due to their unique V-shaped structures, they have large off-diagonal first hyperpolarizability tensors or nonlinear anisotropy, which is an advantage in their practical applications over conventional donor-π-acceptor (D-π-A) NLO-phores. The systematic substitutions of terminal donor/acceptor groups as well as the extension of π-conjugation along the V-shape in these derivatives have been evaluated to guide a purpose-oriented synthesis of NLO material. All the systems in the present study have been categorized into Set-I and Set-II with D-π-A-π-D and A-π-D-π-A configurations, respectively. These designed derivatives show large amplitudes of βz values. For example, systems 3N (6,9-[(N=C=Ph-NO2)2]-B10H12) and 4N (6,9-[((N=C=Ph)2-NO2)2]-B10H12) have βz amplitudes as large as 34.16 and 276.91 × 10(3) a.u. which are 380 and 3000 times larger than those of a typical NLO molecule of urea, respectively. Remarkably, the substitution of nitrogen atoms with 6,9 hydrogen atoms in decaborane is shown to cause a lone pair back donation to vacant p orbitals of 6,9 boron atoms of the decaborane basket. This p orbital overlapping verticalizes the V-arms of the decaborane derivatives and boosts their nonlinear anisotropies due to their larger off-diagonal tensor components. The nonlinear anisotropy values are significantly larger, ranging from 1 (minimum in system 1) to 31.90 (maximum in system 3A) due to their unique V-shape. Comparison of their efficiencies with standard molecules demonstrates that our designed organic-inorganic hybrid molecules have significant potential as excellent candidates for NLO applications.

Water oxidation is a key half reaction in the energy conversion scheme. The reaction mechanism for the oxidation of H2O to O2 catalyzed by single-Ru-substituted polyoxometalates, [Ru(III)(H2O)XW11O39](n-) (X = Si(IV), Ge(IV)), was investigated by means of density functional calculations. The electronic structure of the pre-activation intermediates indicates that the aqua ligand is prone to accommodate the proton coupled electron transfer (PCET) process to achieve the active group [Ru(V)=Oa], and the high valent oxo-ruthenium(V) species are responsible for the O-O forming event. Three possible proton acceptors were designed for the rate-determining step (Ob, Oa, and H2O), the calculated results support that the bridge Ob atom of the polytungstate ligand will act as the most favorable proton acceptor in the O-O bond formation, with an energy barrier of 28.43 kcal mol(-1). A detailed information of the peroxidic intermediates in the oxidation process was also characterized, both the peroxo-species [Ru(IV)(OO)SiW11O39](6-) and [Ru(V)(OO)SiW11O39](5-) show the six-coordinate isomer with an open terminal geometry is more favorable than the close seven-coordinate ones. In addition, the replacement of the heteroatom in XO4(n-) can effectively tune the catalytic activity of polyoxometalates, in the order of Ge(IV)Si(IV).

Herein we designed and synthesized a series of cationic iridium(III) complexes with a phenylbenzoimidazole-based cyclometalated ligand, containing different numbers of carbazole moieties from zero to three (complexes 1–4). The photophysical and electrochemical properties of this series have been systematically investigated. The complexes exhibit strong luminescence in both solution and in neat films, as well as excellent redox reversibility. Introducing carbazole groups into the complexes is found to lead to substantially enhanced photoluminescence quantum efficiency in the neat film, but has little effect on the emitting color and excited-state characteristics as supported by density functional theory (DFT) results. DFT calculations also suggest that functionalized complexes 2–4 reveal better hole-transporting properties than 1. More importantly, all complexes effectively reduce the degradation reaction to some extent in metal-centered (3MC) excited-states, demonstrating their stability. Further studies indicate that restriction of opening of the structures in the 3MC state is caused by the unique molecular conformation of the phenylbenzoimidazole ligand, which is first demonstrated here in cationic iridium(III) complexes without intramolecular π–π stacking. These results presented here would provide valuable information for designing and synthesizing highly efficient and stable cationic iridium(III) complexes suitable for the optical devices.

Polyoxometalate-TiO(2) composites have been successfully introduced into the photoanode of dye-sensitized solar cells to reduce the recombination of the electrons, which results in a longer electron lifetime. The performance of the cells with the polyoxometalate-modified photoanode is better than the cell with a pure P25 photoanode. The effect of the polyoxometalate was studied by electrochemical impedance spectroscopy and open-circuit voltage decay measurement. The results show that the electron lifetime becomes longer following an increase in the amount of the polyoxometalate.

A new cationic Ir(III) complex based on a dendritic ancillary ligand has been designed and synthesized, which simultaneously exhibits piezochromic luminescent (PCL) behavior and aggregation-induced emission (AIE) property for the first time.

Zeolitic Imidazolate Framework-8 (ZIF-8), for the first time for ZIFs, exhibits a remarkable capacity for the anticancer drug 5-fluorouracil (5-FU), around 660 mg of 5-FU/g of ZIF-8, and presents a pH-triggered controlled drug release property. These prove ZIF-8 to be a valuable candidate for delivery of anticancer agents and reveal its potential applications in the treatment of cancer.

A new organic-inorganic hybrid, [Cu(en)(2)](3){[Cu(en)(2)][H(6)SiNb(18)O(54)]}·22H(2)O (1, en = ethylenediamine) containing the crescent-shaped polyoxoanion [H(6)SiNb(18)O(54)](8-) and copper-organic cations has been successfully synthesized, and elemental analyses, IR spectra, thermogravimetric analyses and single-crystal X-ray diffraction were investigated.

The structural and electronic properties of [PW(12)O(40)](3-) (PW(12)) anion deposited on a graphene layer are investigated by using periodic density functional theory. The equilibrium geometries of graphene-PW(12) (G-PW(12)) are examined based on six different configurations. The adsorption energy and charge transfer between PW(12) and graphene are calculated and analyzed. We found that the interaction between PW(12) and graphene are noncovalent. The formation of G-PW(12) complex is theoretically predicted to be feasible from an energetic perspective with electron transfer from the PW(12) to graphene.

DFT investigations have been carried out on encapsulation of Lindqvist-type W(6)O(19)(2-) anion inside hydrogenated (n,n) armchair single-walled carbon nanotubes (h-CNTs) with n = 8, 9, 10 to understand the confinement effect of the CNTs on the rotation of W(6)O(19)(2-). The energy-decomposition analysis (EDA) of interaction between W(6)O(19)(2-) and CNTs shows that with the increase of confinement effect from n = 8, 9, to 10, the destabilizing ΔE(Pauli) plays a more important role in the relative orientation of W(6)O(19)(2-) inside CNTs. For W(6)O(19)(2-)@(9,9) h-CNT, the most stable orientation appears at the y/z angle 45°/36°. The confinement effect reduces significantly the energy gap of W(6)O(19)(2-)@(n,n) h-CNT (n = 8, 9, 10) compared with free W(6)O(19)(2-). Electron transfer from the W(6)O(19)(2-) to CNT is observed.

A long-term stable Pt counter electrode modified by POM-based multilayer film has been fabricated by the electrochemical deposition method, which can markedly increase short-circuit photocurrent, open-circuit voltage and the conversion efficiency when used in dye-sensitized solar cells (DSSCs).

We report the synthesis and characterization of two cationic iridium(III) complexes with dendritic carbazole ligands as ancillary ligands, namely, [Ir(ppy)(2)L3]PF(6) (1) and [Ir(ppy)(2)L4]PF(6) (2), where L3 and L4 represent 3,8-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-1,10-phenanthroline and 3,8-bis(3',6'-di-tert-butyl-6-(3,6-di-tert-butyl-9H-carbazol-9-yl)-3,9'-bi(9H-carbazol)-9-yl)-1,10-phenanthroline, respectively. Their photophysical properties have been investigated and compared. The results have shown that complex 2 is aggregation-induced phosphorescent emission (AIPE) active and exhibits the highest photoluminescent quantum yield (PLQY) of 16.2% in neat film among the reported cationic Ir(III) complexes with AIPE activity. In addition, it also enjoys redox reversibility, good film-forming ability, excellent thermal stability as well as off/on luminescence switching properties, revealing its potential application as a candidate for light-emitting electrochemical cells and organic vapor sensing. To explore applications in biology, 2 was used to image cells.

The electronic structures and photophysical properties of eight Pt-complexes with different N-heterocyclic carbene ligands and potential to serve as light emitting diode materials were investigated by density functional theory and time-dependent density functional theory, employing the BP86 functional for geometry optimisations, SAOP potential for excited state calculations and all-electron TZ2P basis set throughout. Non-radiative and radiative decay rate constants were determined for each system through analyses of the geometric relaxations, d-orbital splitting and spin-orbit couplings at the optimised S(0) and T(1) geometries. Three Pt-systems bound to two N-heterocyclic carbenes were shown to be nonemissive, while a fourth was shown to be emissive from the T(1) excited state. Similar T(1)-initated emission was observed for three other Pt-systems investigated, each bound to four N-heterocyclic carbenes, while a fourth similarly tetra-ligated system showed T(2)-initation of emission. The results highlight the coupling of ligand-identity to photophysical properties and more importantly, the potential for rational optimisation and tuning of emission wavelengths and phosphorescent efficiencies. Encouragingly, two of the tetra-N-heterocyclic carbene ligated systems show strong potential to serve as highly-efficient blue and green light emitting materials, respectively.

With the bottom-up design principle, we use metal-ions to bridge the predesigned tectons (1 [(H(2)L(1))(2)(Mo(8)O(26))]·4H(2)O and 3 [(H(2)L(2))(L(2))(0.5)(Mo(8)O(26))(0.5)]·H(2)O) so that two higher dimensional γ-octamolybdate based inorganic-organic hybrid compounds 2 [Cu(I)(2)(L(1))(3)(Mo(8)O(26))(0.5)] and 4 [Ni(L(2))(2)(HL(2))(2)(Mo(8)O(26))]·4H(2)O are successfully obtained.

Three cationic iridium complexes containing 4,7-bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-1,10-phenanthroline (L(1)) and 4,7-bis(3',6'-di-tert-butyl-6-(3,6-di-tert-butyl-9H-carbazol-9-yl)-3,9'-bi(9H-carbazol)-9-yl)-1,10-phenanthroline (L(2)) as the ancillary ligands, namely, [Ir(ppy)(2)(L(1))]PF(6) (1), [Ir(ppy)(2)(L(2))]PF(6) (2) and [Ir(oxd)(2)(L(2))]PF(6) (3) (ppy is 2-phenylpyridine, oxd is 2,5-diphenyl-1,3,4-oxadiazole), have been designed and prepared. With more intramolecular rotational units on the ancillary ligand (L(2)), 2 and 3 possess a unique aggregation-induced phosphorescent emission (AIPE) property. This phenomenon was unprecedentedly observed in the cationic iridium(III) complexes. In order to investigate the underlying mechanism of this AIPE behavior, their photophysical, temperature-dependent aggregation properties as well as theoretical calculations, were performed. The results suggest that restricted intramolecular rotation is responsible for the AIPE of cationic complexes. Moreover, photoluminescent quantum yields in the neat film, thermal stabilities and off/on luminescence switching of 2 were investigated, revealing its potential application as a candidate for LECs and organic vapor sensing.

A sandwich-type anionic cluster of a new lacunary building block [P(2)W(13)O(51)](14-) has been prepared: [H(6){P(2)W(13)O(51)}(2)Sb(4)](10-) (1) was synthesized in a one-pot self-assembly reaction of [H(2)P(2)W(12)O(48)](12-) with C(4)H(4)KO(7)Sb.0.5H(2)O and characterized by single-crystal X-ray analysis, IR, thermogravimetric analysis, elemental analysis, UV, NMR and electrochemistry. 1 represents the first dimetric, antimony-containing polyoxoanion derived from a vacant Dawson-type tungstophosphate.

The complexes AlQ(3) and Ir(ppy)(3) (Q = 8-hydroxyquinolate; ppy = 2-phenylpyridyl) are typical green emitting fluorescence and phosphorescence materials, respectively. Here we hybridize Ir(ppy)(3) with AlQ(3) to investigate the optoelectronic properties of the Ir(III)-centred derivatives including (ppy)(2)IrQ, (ppy)IrQ(2) and IrQ(3) by using density functional methods. Our calculations show that the derivative Ir(III) complexes are red emitting phosphorescence materials. The characters of the lowest triplet excited states for these Ir(III) complexes are mainly dominated by the 8-hydroxyquinolate ligand. IrQ(3) and (ppy)(2)IrQ possess good electron transfer performance, while (ppy)IrQ(2) might have hole transport properties.

In the present paper, the electronic structures and bonding features between the ruthenium atom and nitrido ligand of known nitrido ruthenium (VI) porphyrin and hexavalent ruthenium nitrido derivative of Keggin typical polyoxometalate (POM) have been investigated by using density functional theory (DFT) calculations and natural bond orbital (NBO) analysis. The results show that the Keggin POM complex and porphyrin complex have the Ru[triple bond]N triple bond, the NBO calculations yield a nitrido ligand charge close to zero in both complexes because of the charge transfer from the rich-electron nitrido ligand to the ruthenium center. The molecular orbitals predict that the ruthenium porphyrin complex would generate oxidized species with no change in the oxidation state of the metal center; however, the ruthenium center of the POM complex would be oxidized in a one-electron-oxidation process because of the different HOMO character, and moreover, the spin unrestricted calculations confirm this prediction made by molecular orbital analysis. On the other hand, both complexes have the same reduced center, the RuN unit, and the one-electron-reduction process weakens the bonding interaction between the ruthenium atom and nitrido ligand for both complexes because the antibonding LUMO is occupied. Compared with the porphyrin complex, the POM complex possesses a higher RuN composition and lower energy pi* antibonding orbital according to gas-phase and solvent calculations.