Synthese und Struktur von neuen Germanium‐Phosphor‐Heterocyclen mit einem Ge 2 P 2 ‐Ringgerüst

Synthesis and Structure of New Germanium‐Phosphorus Heterocycles Containing a Ge 2 P 2 ‐Framework Mes( t Bu)GeF 2 (Mes = 2,4,6‐trimethylphenyl) reacts with two equivalents of [LiPH 2 · dme] (dme = dimethoxyethane) to give the 1,3,2,4‐diphosphadigermetane 1 which was characterized by an X‐ray structure analysis. Surprisingly, only the trans ‐configurated isomer (with regard to the t Bu groups at germanium) is formed. In solution at 25°C the latter compound exists as a 1:1 mixture of cis and trans isomers (with regard to the H atoms at phosphorus). Lithiation at phosphorus with t BuLi gives the corresponding 1,3‐dilithio derivative which reacts with t BuHgCl to form the 1,3‐dimercurio derivative 2 . Photolysis of 2 with visible light leads to 3 , the first derivative of a 1,3‐diphospha‐2,4‐digermabicyclo[1.1.0]butane with t Bu/ t Bu‐ exo,exo configuration. As another product of the photolysis the trimercurio compound 5 is isolated and characterized by an X‐ray structure analysis.