Synthesis and structural characterization of Lindqvist type mixed-metal cluster anion [V2W4O19]4− in discrete and coordination polymer compounds

•Synthesis and characterization of Lindqvist type mixed-metal polyoxometalates.•Compounds have been characterized by single crystal X-ray crystallography.•Discrete cluster as well as coordination polymer containing compounds.•In these crystal structures, supramolecular interactions are explored.•Compounds are additionally characterized by 51V NMR spectroscopy and ICP analysis.

Two vanadium substituted Lindqvist type tungsten heteropolyanion containing compounds with molecular formulae [HMTAH]2[H2V2W4O19]·4H2O (1) and [Na2(H2O)4]n[H2V2W4O19]n·2nHMTA·2nH2O (2) have been synthesized, where HMTA is hexamethylenetetramine. Compound 1 is a discrete compound, whereas, compound 2 is a coordination polymer. Compounds 1–2 are characterized by routine elemental analyses, FT-IR spectroscopy, electronic absorption spectral analyses, thermogravimetric studies and single crystal X-ray crystallography. The presence of vanadium in the cluster anion is confirmed by 51V NMR spectroscopy, EDS and ICP analyses. The crystal structures of compounds 1 and 2 are refined in orthorhombic space group Immm and monoclinic space group C2/c respectively.

Graphical abstractCompounds [HMTAH]2[H2V2W4O19]·4H2O (1) and [Na2(H2O)4]n[H2V2W4O19]n·2nHMTA·2nH2O (2) have been synthesized from an aqueous solution and characterized by routine analysis and single crystal X-ray crystallography. Compound 1 is a discrete cluster containing compound, whereas compound 2 is coordination polymer. Compounds 1 and 2 are additionally characterized by 51V NMR spectroscopy.Figure optionsDownload full-size imageDownload as PowerPoint slide