Synthesis and Characterisation of Molecular Bismuth Phosphorus Compounds Containing Bi 2 Units with Bi–Bi Single and Double Bonds

The compound [BiP(SiPh 2 t Bu) 2 ] 2 ( 1 ), featuring a Bi–Bi double bond and two Bi–P single bonds, has been obtained from thereaction of BiCl 3 with the lithium phosphanide LiP(Si t BuPh 2 ) 2 .As a byproduct of this transmetallation/redox reaction the diphosphane P 2 (Si t BuPh 2 ) 4 ( 2 ) has been isolated. This compound shows a remarkably short P–P bond due to π interactions of the phosphorus atoms. The reaction of the dilithium phosphandiide Li 2 PSi t BuPh 2 with BiCl 3 yielded the bicyclic compound [Bi 2 (PSiPh 2 t Bu) 4 ] ( 3 ), exhibiting a Bi–Bi single bond. NMR studies of 3 show the availability of four different P atoms, as observed in the crystal structure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)