Preparation and reactions of difluoromethylene-diphosphanes and 2,2,4,4-tetrafluoro-1,3-diphosphetanes

Reactions of organo-bistrimethylsilylphosphanes with CF 2 Br 2 has led to diphosphetanes 1: The stereochemistry of the products were proved by x-ray-diffraction and detailed nmr analysis; predominantly trans-orientated products 1 are formed. The intermediate formation of phosphaalkenes and their thermal stability will be discussed. In addition, reactions of the silyl-substituted phosphanes with other fluoro-methanes will be reported. Reactions of R 2 PSiMe 3 (R = Ph, Bu t , Me) with CF 2 Br 2 only yields R 2 PCF 2 Br. Synthesis of compounds of the type R 2 PCF 2 PR 2 were achieved by reaction of R 2 PLi with CF 2 Br 2 . These difluoromethylene-bridged compounds have been fully characterized. Oxidation reactions, e.g. sulfurization, yields fourcoordinated derivatives. The complexing abilities of the diphosphanes R 2 PCF 2 PR 2 and of the diphosphetanes (RPCF 2 ) 2 have been studied. For example, the reaction with (tht)AuCl formed the trans-orientated compound 2 . Other studies reported are concerned with metal carbonyl derivatives.