Bis[3,4,5,6-tetrabrom-1,2-benzoldiolato(2-)]-(pyrrolidiniomethyl)silicat-Acetonitril-Solvat [(C6Br4O2)2SiCH2(H)NC4H8 · CH3CN]: Synthese sowie Kristall- und Molekülstruktur eines zwitterionischen [lambda]5-Spirosilicats

Abstract

Single crystal X-ray studies on bis[3,4,5,6-tetrabromo-1 ,2-benzenediolato(2- )](pyrrolidiniomethyl)silicate acetonitrile solvate [(C6Br40 2hSiCH2(H)NC4H8 · CH3CN; monoclinic, P2t/c, a = 808.5(4), b = 1533.0(8), c = 2212.6(1) pm, ß = 97.67(2)0 , Z = 4] revealed a zwitterionic structure with a pentacoordinate, formally negatively charged silicon atom and a positively charged ammonium moiety. The silicon atom is surrounded by four oxygen atoms and one carbon atom in a trigonalbipyramidal fashion, with the carbon atom in an equatorial position. The structure is displaced by 7.0% from the trigonal bipyramid towards the square pyramid. The zwitterion and the CH3CN molecule form intermolecular N-H · · · N hydrogen bonds