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Monofunctionalized alkylimido derivatives of hexamolybdate, (Bu4N)2[Mo6O18(≡N–R)] (R = methyl, Me; ethyl, Et; n-propyl, n-Pr; i-propyl, i-Pr; n-butyl, n-Bu; t-butyl, t-Bu; cyclohexyl, Cy; n-hexyl, Hex; and n-octadecyl, Ode), have been prepared in high purity and good yield by the reaction of [Bu4N]4[α-Mo8O26] with appropriate aliphatic amine hydrochlorides in anhydrous acetonitrile, using N,N′-dicyclohexylcarbodiimide (DCC) as the dehydrating agent. Eight compounds have been determined by single crystal X-ray diffraction analysis and all compounds have been studied with 1H-NMR, IR, UV-vis, ESI mass spectrometry and cyclic voltammetry. A structural and 1H-NMR study show β hydrogen atoms of those alkylimido derivatives of hexamolybdate have strong Brønsted acidity compared to the hydrogen atoms in other positions. [ABSTRACT FROM AUTHOR]

Abstract: Two new compounds were obtained by modifying hexavanadate cores with pentaerythritol in aqueous solution, however, re-crystallized in water and acetonitrile, respectively. The molecular structures for (Bu4N)2[V6O13{(OCH2)3CCH2OH}2·H2O] (1) and (Bu4N)2[V6O13{(OCH2)3CCH2OH}2·4CH3CN] (2) (Bu, n-butyl) have been characterized by FT-IR, UV–Vis, and single crystal X-ray diffraction. Compound 1 and 2 crystallize in monoclinic and triclinic space groups, respectively. Compound 1 shows supramolecular chirality in two-dimensional molecular assemblies while 2 does not have such chiral structure. The role of solvent molecules to the formation of supramolecular chirality in self-assembly architectures of polyoxometalates-based hybrid materials is discussed based on these two crystal structures. [Copyright &y& Elsevier]

Abstract: An organic–inorganic hybrid compound, (Bu4N)2[Mo6O18(NAr)] (Ar= p-BrC6H4) has been synthesized via the DCC dehydrating protocol of the reaction of [α-Mo8O26]4− with 4-bromoaniline hydrochloride in anhydrous acetonitrile, which has been characterized by UV–Vis spectra, 1H NMR and single crystal X-ray diffraction study. By comparing the UV–Vis spectra, which were used to monitor the reaction, the optimum preparative condition for this compound was also determined. This compound crystallizes in the monoclinic space group P21/n, which is featured in a terminal para-bromophenylimido group linked to an Mo atom of a hexamolybdate cluster by a Mo–N triply bond. In addition, there are π–π dimerization of the neighboring cluster anions though the parallel aromatic rings in their crystals. [Copyright &y& Elsevier]