Über die Darstellung von P-Chlor-substituierten Ν,N′-Dimethylharnstoff-verbrückten Diphosphorverbindungen, deren Enthalogenierung mit Oxalsäurebis(trimethylsilylester) und anschließende Oxidation mit Tetrachlororthobenzochinon / Preparation of P-Chloro-Substituted N′,N′-Dimethylurea-Bridged Diphosphorus Compounds, their Dehalogenation with Oxalic Acid Bis(trimethylsilyl) Ester and Subsequent Oxidation with Tetrachloroobenzoquinone

Abstract

Reaction of N,N′-dimethyl-N,N′-bis(trimethylsilyl)urea (1) with dichlorophosphines. RPCl2 (R = Et: 14; R = Pr: 15) has furnished the P-chloro-substituted acyclic diphosphorus compounds, 16 and 17. In the analogous reaction of 1 with Ph2PCl the corresponding bis(diphenylphosphino)-substituted derivative, 21 was formed. Dehalogenation of 11, 16 and 17 with oxalic acid bis(trimethylsilyl) ester, 22 has produced the mixed-valent cyclic λ3P,λ4P-diphosphorus compounds, 23-25 in almost quantitative yield. Oxidation of the λ3P atom in 23-25 with tetrachloroorthobenzoquinone, 26 has given rise to partial cleavage of the P-P bond, and only moderate yields of the products, 29, 31 and 32, have been obtained. The characterization of the various compounds obtained rests, especially, on their 1H and 31P NMR spectra, and on a study of their mass spectral fragmentation pattern