Tetrakis-pentamethylcyclopentadienyl-cyclotetrastiban (PcpSb)4 : Synthese, Molekül-und Kristallstruktur / Tetrakis-pentamethylcyclopentadienyl-cyclotetrastibane (PcpSb)4 : Synthesis, Molecular and Crystal Structure

Abstract

Abstract Reaction of SbCl3 with KPcp (Pep = pentamethylcyclopentadienyl) in etheral solution at -78 °C affords dimeric pentamethylcyclopentadiene and orange-red (PcpSb)4 in high yield. 1H, 13 C NMR, IR, UV and mass spectra are reported. The tetrameric structure was found by a crystal structure determination carried out with X-ray diffraction data collected at -50 °C (928 independent observed reflexions. R = 0.055). Crystal data: tetragonal, space group I41/amd, a = 2400.0(5), c = 781.7(5) pm, Z = 4. The (PcpSb)4 molecules have a non-planar Sb4 ring with Sb -Sb bond lengths of 285.6(1) pm, one η1-Pcp ring is attached to each Sb atom. Contrary to the solid state structure, monomeric molecules are found in benzene and hexane solutions.