Copper(II)–ethylenediamine linked Nb24 dimer with one dimensional chain architecture

Abstract

The one-pot synthesis of one-dimensional chain polyoxoniobate based on Nb24 building block, [{Cu(en)2(H2O)2}{Cu(en)2(H2O)}2(H2en)10][{(Nb24O72H6)[Cu(en)2]2}2Cu(en)2]·72H2O (1, en = ethylenediamine), are firstly presented. Compound 1 was structurally and compositionally characterized in the solid state by single-crystal X-ray diffraction, IR、UV spectroscopy, powder X-ray diffraction, as well as thermogravimetry and elemental analyses. The results indicate that 1 comprises a dimeric polyanion [{(Nb24O72H6)[Cu(en)2]2}2Cu(en)2]26− (1a), three copper complex cations, ten di-protonated en cations and 72 crystal water molecules. In 1a, two [{Nb24O72H6}{Cu(en)2}]16− fragments are fused together by two {Cu(en)2} bridges through one terminal oxygen atom and one bridging oxygen atom from Lindqvist units on adjacent clusters to form dimeric [(Nb24O72H6){Cu(en)2}2]228− ({Cu2Nb24}2) unit. The adjacent {Cu2Nb24}2 dimeric units are further linked together by a {Cu(en)2} ligand forming a straight 1D chain. In addition, compound 1 can be used to decolor methyl blue, and the decolorization rate can reach 94.86% after 3 min under the irradiation of natural light.