Metastable P-Tellurium-Substituted Phosphaalkenes: Formation, 125Te- and 31P-NMR Spectroscopic Characterization, and Decomposition

AbstractThe formation and decomposition of P-tellurium-substituted phosphaalkenes was followed by 31P- and 125Te-NMR spectroscopy. Acyclic compounds with C˭P-Te moieties are in general thermally labile, but bulky substituents enhance the lifetime of a number of species. The P-chlorophosphaalkene (Me3Si)2C˭PCl (1a) reacts with the disilyltelluride (iPrMe2Si)2Te (2) leading to the mixed-substituted telluride (Me3Si)2C˭PTeSiMe2iPr 3a which reacts with another equivalent of 1a furnishing the tellurobis(phosphaalkene) [(Me3Si)2C˭P]2Te (4a). 4a is a shortlived compound decomposing thermally with precipitation of elemental tellurium, leading to a known diphosphabicyclobutane 5a. In a similar way, the bulkier P-chlorophosphaalkene (iPrMe2Si)2C˭PCl (1b) reacts with (iPrMe3Si)2Te furnishing [(iPrMe2Si)2C˭P]2Te (4b), which loses tellurium much more slowly than 4a and can be kept in cold solutions for an extended time. Reactions of in situ-prepared lithium aryltellurolates LiTeAr 6 – 9 [Ar˭Ph: 6, Ar˭2,4,6-Me3Ph (˭Mes...