Novel Binary Compounds of Group 15 Elements: Synthesis and Characterisation of [Sb 4 (PSiMe 2 Thex) 4 ], [Sb 4 (AsSi i Pr 3 ) 4 ] and [Sb 2 (PSiPh 2 t Bu) 4 ]

The low‐temperature reactions of Me 2 ThexSiPLi 2 (Thex = CMe 2 i Pr) and i Pr 3 SiAsLi 2 with SbCl 3 in a 3:2 molar ratio yields the cage compounds [Sb 4 (PSiMe 2 Thex) 4 ] ( 1 ) and [Sb 4 (AsSi i Pr 3 ) 4 ] ( 2 ), respectively. The metal salt SbBr 3 reacts with t BuPh 2 SiPLi 2 at −70 °C to give the bicyclic compound [Sb 2 (PSiPh 2 t Bu) 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 (As 4 S 4 ). The central structural motif is an Sb 4 Y 4 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 Sb 2 bridgehead. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)