![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The tetramethylguanidinyl-substituted phosphines 3a–3c and 4a–4d were prepared by reaction of N,N,N′,N′-tetramethylguanidine 1 (TMG) or N-trimethylsilyl-N′,N′,N′,N″-tetramethylguanidine 2 with RPCl2 or RR′PCl. In the related reaction of MeAsCl2 with 2 only the mono-substituted compound 5 was obtained. Typical phosphorus(III) reactivity was observed for the new phosphorus(III)-TMG compounds: e.g. in the reaction of 3a–3c, 4c and 4d with methyl iodide quaternisation took place (only at the phosphorus atom: no reaction at nitrogen was observed). The compounds 3a–3c and 4c react readily with sulfur, selenium and tellurium to form the corresponding chalcogenide derivatives. The oxidative addition of 9,10-phenanthraquinone to 3b led to the dioxa-λs-phosphole 12. Reaction of 2 with the chlorospirophosphorane (C5H4O2)2PCl gave the P-tetramethylguanidinyl-substituted derivative 13. The X-ray structure determination of 4c, 8c and 9 shows short P[sbnd]N bonds consistent with partial double bond character. Delocalisation involving the sulfur atom may enhance this double bond character leading to shorter P[sbnd]N bonds in 8c and 9 than in 4c.
