An organo-functionalized metal-oxide cluster, [V6IVO6{(OCH2CH2)2N(CH2CH2OH)}6], with Anderson-like structure

A new polyoxovanadium cluster compound, [(V6O6)-O-IV{(OCH2CH2)(2)N(CH2CH2OH)}(6)]center dot 0.5CH(3)CN, was synthesized and characterized by single-crystal X-ray diffraction analysis, FTIR and UV-vis spectroscopy, and TGA. The cluster is composed of a fully reduced cyclic {V6N6O18} framework, which adopts an Anderson-like structure and is comprised of a ring of six edge-sharing {VO5N} octahedra incorporating six {(OCH2CH2)(2)N (CH2CH2OH)} ligands. Two (OCH2CH2-) arms of each of the six triethanolamine ligands are directly incorporated into the oxometalate core and the third {-CH2CH2OH} arm remains pendant. In the condensed phase, the clusters form discrete hcp layers through inter-cluster hydrogen bonding. These layers stack through soft chemical interactions to form a 3D network structure. The neutral cluster, [(V6O6)-O-IV{(OCH2CH2)(2)N (CH2CH2OH)}(6)], is the isopolyoxovanadium analogue to the cationic clusters contained in a series of heteropolyoxovanadium compounds previously introduced by our laboratory, e.g., [(LiV6O6)-O-IV{(OCH2CH2)(2)N (CH2CH2OH)}(6)](+); its existence shows that a heteroatom is not required to form or stabilize the common organofunctionalized vanadium oxide framework: [(V6O6)-O-IV{(OCH2CH2)(2)N(CH2CH2OH)}(6)]. To the best of our knowledge, the isopolyoxovanadium and heteropolyoxovanadium clusters represent the first reported isopoly-heteropoly analogues in the polyoxometalate field. We compare the TGA profile, FTIR and UV-vis spectra of the new compound with two of its cationic heteropoly analogues.