Baokuan Chen

Three New Imidazole-Functionalized Hexanuclear Oxidovanadium Clusters with Exceptional Catalytic Oxidation Properties for Alcohols

Cluster cat: Three new imidazole-functionalized neutral hexanuclear vanadium clusters have been prepared, one of which shows exceptional catalytic activity in the selective aerobic oxidation of alcohols (see scheme). Furthermore, these new polyoxovanadium clusters can be readily recycled and reused with unchanged catalytic activity. A plausible catalytic cycle is also proposed.

Cation-Induced Synthesis of New Polyoxopalladates

Seven polyoxopalladate compounds, [Pd(15)(SeO(3))(10)(μ(3)-O)(10)](10-), with Na(+) (1) and K(+) (2) as counterions, and Na(6)[M(II){Pd(12)(SeO(3))(8)(μ(4)-O)(8)}]·nH(2)O (M = Co (3), Zn (4), Ni (5), Cu (6), Mn (7); n = 7-9), have been prepared and characterized by SXRD, FT-IR, UV-vis, EA, TGA, and ESI-MS. These compounds comprise two distinct cluster configurations, {Pd(15)} and {M(II)Pd(12)}, which reveals the possibility of obtaining desired noble metal clusters with a certain nuclearity by using different cations as potential structural directing or template agents in synthesis. All compounds showed apparent absorptions in the visible light region, while 3 and 7 were found to show paramagnetic behavior typical of mononuclear Co(II) and Mn(II) complexes with zero-field splitting.

Controlled solvothermal synthesis of novel organic functionalized polyoxovanadates

Four novel organic functionalized polyoxovanadates are solvothermally synthesized by altering the reaction temperature and using different organoarsonic acids. These POVs are fully characterized and the phase transitions between different POVs structures are confirmed by X-ray diffraction analyses. Such a transition is temperature-dependent and thus controlled synthesis of new POVs can be achieved.

Three new polyoxoniobates constructed from Lindqvist-type hexaniobate and copper–amine complexes

Three new polyoxoniobates constructed from Lindqvist-type [Nb6O19]8− and copper–amine complexes, [Cu(1,2-dap)2]{[Cu(1,2-dap)2]2[Nb6O19H2]}u2009·u200910H2O (1), [Cu(1,3-dap)2]2{[Cu(1,3-dap)]2[Nb6O19]}u2009·u200910H2O (2), and [Cu(en)2]0.5{[Cu(en)2]2[Nb6O19H3]}u2009·u200912H2O (3) (1,2-dapu2009=u20091,2-diaminopropane, 1,3-dapu2009=u20091,3-diaminopropane, and enu2009=u2009ethylenediamine), have been synthesized and characterized by elemental analyses, infrared, powder X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectrum, and single-crystal X-ray diffraction. Compounds 1–3 exhibit bisupporting hexaniobate cluster structure, each with a [Nb6O19]8− cluster decorated by two copper–amine complexes. In 1, adjacent bisupporting clusters are connected with one [Cu(1,2-dap)2]2+ fragment via Cuu2009···u2009O weak interactions to generate a 1-D supramolecular chain structure. In contrast to 1, each bisupporting cluster in 2 is linked to another four neighboring ones through four [Cu(1,3-dap)2]2+ fragments by Cuu2009···u2009O weak interactions to yield a 2-D supramolecular network. Different from 1 and 2, no detected interaction was found between bisupporting cluster and [Cu(en)2]2+ in 3, the [Cu(en)2]2+ fragment merely acts as an isolated countercation.

A new synthetic approach to functionalize oxomolybdenum complexes

A new synthetic approach is developed and nine distinct organic functionalized oxomolybdenum complexes, 1–9, are synthesized and fully characterized. Specifically by altering the functional groups on imidazoles we succeeded in making a series of crystalline structures with unique underlying topologies and/or functionalities. These imidazole derivatives can act as ligands, structural directing agents, counter cations and simultaneously, solvents where the reactions and the crystallization occur.

Two chiral multinuclear palladium(II) complexes comprising alternately arranged isomerous hexanuclear clusters

Two new chiral hexanuclear palladium(II) complexes [Pd6(Cys)4(CysH)4][Pd6(CysH)8]Cl4·24H2O (1) and [Pd6(HCys)10](NO3)2·11H2O (2) are prepared through careful control of the reaction conditions. Both complexes comprise two alternately arranged isomerous hexanuclear Pd(II) clusters. As supported by ESI-MS spectra and CD analyses, the integrity of the structures can be maintained in aqueous solution and the chirality of L-Cys ligands can be preserved to the multinuclear Pd complexes.

A Highly Symmetric Ionic Crystal Constructed by Polyoxoniobates and Cobalt Complexes for Preferential Water Uptake over Alcohols

An ionic crystal assembled by PNb12O40(VO)6 and tris(1,2-diaminopropane)cobalt complexes was hydrothermally isolated and structurally characterized by routine methods. The compound exhibits three-dimensional channels with a pore size of 3.68 Å × 2.30 Å and composed of hydrophilic oxygen atoms of polyanions and hydrophobic -CH3 groups of 1,2-diaminopropane ligands. With increasing vapor pressure, the compound shows preferable adsorption toward water over alcohols, and a gate-opening behavior was deduced from the water adsorption isotherm.

Chiral Dodecanuclear Palladium(II) Thio Cluster: Synthesis, Structure, and Formation Mechanism Explored by ESI-MS and DFT Calculations

The chiral dodecanuclear palladium(II) thio cluster LaPd12(C3H5NO2S)3(C3H6NO2S)21 (1) was prepared by reacting l-cysteine (l-Cys) with PdCl2 and La2O3 in aqueous solution under carefully controlled conditions. Compound 1 was structurally characterized by single-crystal XRD, TGA, IR, UV-vis, (13)C NMR, and CD spectroscopy. Insight into the dimerization process of 1 was obtained by ESI-MS and DFT calculations.