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

Abstract

Self assembly of NaVO 3, Na 2MoO 4·2H 2O and NiCl 2·6H 2O with the assistance of organic liginds under hydrothermal conditions results in two molybdovanadates [Ni(enMe) 2] 4{[Ni(enMe) 2(H 2O)] 2[Ni(enMe) 2][(V VMo VI 8V 4 IVO 40)(V IVO) 2] 2}·10H 2O ( 1) and [Ni(enMe) 2] 5{[Ni(enMe) 2] 2[(V VMo VI 4Mo V 4V 4 IVO 40)(V IVO) 4] 2}·2H 2O ( 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 [(V VMo 8V 4 IVO 40)(V IVO) 2] 7−, one [Ni(enMe) 2] 2+ bridging fragment and two decorated nickel(II) complexes. Polyxoxanion 2 consists of two tetracapped molybdenum–vanadium polyoxoanions [(V VMo VI 4Mo V 4V 4 IVO 40)(V IVO) 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.