PREPARATION, CHARACTERIZATION AND X-RAY CRYSTAL-STRUCTURE OF A CHARGE-TRANSFER SALT (DMNP)(4)[SIW12O40]CENTER-DOT-2DMF

The title compound, [(DMNP)(4)SiW12O40. 2DEVIF] (DMNP = 4-dimethylamin o-1-methyl-pyridylammonium; DMF = N,N-dimethyl formamide) has been syn thesized from (TBA)(4)SiW12O40 (TBA- tetrabutylammonium) and DMNP iodi de in acetonitrile. The compound crystallized in P2(1)/n space group f rom DMF solution, and was characterized by elemental analysis, XPS stu dy, IR, ESR and electronic spectra. X-ray structure analysis confirmed the presence of the Keggin structure of SiW12O404-. The sites of four oxygen atoms bonded to Si atom are disordered over 8 possible locatio ns in each anion in the crystal, which increases the symmetry of the p olyanion. The bond distances of Si-O and W=O are 1.636(5)-1.655(5) and 1.632-1.726 Angstrom, respectively. Copyright (C) 1996 Elsevier Scien ce Ltd