Two new supramolecular hybrids based on bi-capped Keggin {PMo12V2O42} clusters and transition metal mixed-organic-ligand complexes

Abstract

Two supramolecular compounds [Cu(imz)2][Cu(phen)(imz)]2{[Cu(phen)]2[PMo6VIMo6VV2IVO42]}(1) and [Co2(2,2′-bpy)4(C2O4)][Co(2,2′-bpy)3][PMo7VIMo5VV2IVO42](2,2′-bpy)0.5·H2O(2)(phen=1,10′-phenanthroline, imz= imidazole, 2,2′-bpy=2.2′-bipyridine) have been synthesized hydrothermally and characterized by elemental analyses, infrared spectrum, UV-Vis, X-ray photoelectron spectroscopy(XPS), electron spin resonance(ESR) spectra, thermogravimetry analyses and single crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses revealed that both the compounds represent the examples of compounds based on the bi-capped Keggin polyoxoanion {PMo12V2O42} and transition metal mixed-organic-ligand coordination complexes. Compound 1 consists of bi-capped Keggin polyoxoanion [PMo12V2O42]5− supported copper coordination groups, which are further inter-connected with two types of copper complex fragments forming a 3D supramolecular framework via π⋯π stacking, C-H⋯O and N-H⋯O hydrothermal bonding interactions. Compound 2 is a new hybrid consisted of polyoxoanion [PMo12V2O42]4−, [Co2(2,2′-bpy)4(C2O4)]2+ and [Co(2,2′-bpy)3]2+. There are no direct interactions in compound 2, but the polyoxoanions together with two different cobalt complex groups construct a 3D supramolecular network through C-H⋯O hydrogen bonding interactions.