Novel binary compounds of group 15 elements: Synthesis and characterisation of [Sb4(PSiMe2Thex)4], [Sb 4(AsSiiPr3)4] and [Sb2(PSiPh 2tBu)4]

Article abstract of DOI:10.1002/ejic.200400610

The low-temperature reactions of Me₂ThexSiPLi₂ (Thex = CMe₂iPr) and iPr₃SiAsLi₂ with SbCl ₃ in a 3:2 molar ratio yields the cage compounds [Sb ₄(PSiMe₂Thex)₄] (1) and [Sb ₄(AsSiiPr₃)₄] (2), respectively. The metal salt SbBr₃ reacts with tBuPh₂SiPLi₂ at -70 °C to give the bicyclic compound [Sb₂(PSiPh₂tBu)₄] (3). Compounds 1-3 were characterised by NMR and IR spectroscopy, mass spectrometry, elemental analysis and single-crystal X-ray diffraction. The structures of 1 and 2 reveal that the both compounds adopt a structure similar to those of realgar (As₄S₄). The central structural motif is an Sb₄Y₄ cage (Y = P, As), consisting of four five-membered rings with common edges. The bicyclic compound 3 is composed of five-membered and three-membered rings sharing a common Sb₂ bridgehead. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.