Two dumbbell-like polyoxometalates constructed from capped molybdovanadate and transition metal complexes

Self assembly of NaVO3, Na2MoO4·2H2O and NiCl2·6H2O with the assistance of organic liginds under hydrothermal conditions results in two molybdovanadates [Ni(enMe)2]4{[Ni(enMe)2(H2O)]2[Ni(enMe)2][(VVMoVI8V4IVO40)(VIVO)2]2}·10H2O (1) and [Ni(enMe)2]5{[Ni(enMe)2]2[(VVMoVI4MoV4V4IVO40)(VIVO)4]2}·2H2O (2), (enMe = 1,2-diaminopropane), which have been characterized by single crystal X-ray diffraction analysis, IR spectroscopy, and elemental analysis. Both of the two compounds exhibit dumbbell-like structures constructed from capped polyoxomolybdovanadates and [Ni(enMe)2]2+ complexes. Polyoxoxanion 1 is composed of two bicapped Keggin-type anions [(VVMo8V4IVO40)(VIVO)2]7−, one [Ni(enMe)2]2+ bridging fragment and two decorated nickel(II) complexes. Polyxoxanion 2 consists of two tetracapped molybdenum–vanadium polyoxoanions [(VVMoVI4MoV4V4IVO40)(VIVO)4]7−, one [Ni(enMe)2]2+ bridging fragment and a nickel(II) decorated fragment. Polyxoxanions 1 and 2 are further linked to form three-dimensional supramolecular networks through extensive hydrogen bonding interactions. In addition, photocatalysis properties of these two compounds have been investigated.