Carbene insertion into a P-H bond: parent phosphinidene-carbene adducts from PH3 and bis(phosphinidene)mercury complexes

摘要

PH3 reacts with the in situ generated N-heterocyclic carbene DippNHC(star) ((NHC star)-N-Dipp = 1,3-bis(2,6-diisopropylphenyl) imidazolin-2-ylidene) to give the phosphanyl-imidazolidine [(NHC star)-N-Dipp-H]-[PH2]. Upon treatment with an ortho-quinone, [(NHC star)-N-Dipp-H]-[PH2] is dehydrogenated to give the parent phosphinidene-carbene adduct (NHC star)-N-Dipp=PH. Alternative routes to [(NHC star)-N-Dipp-H]-[PH2] and (NHC star)-N-Dipp=PH employ NaPH2 and (TMS)(3)P-7 (TMS = trimethylsilyl), respectively, as phosphorus sources. The adduct (NHC star)-N-Dipp=PH and the related adduct (NHC)-N-Dipp=PH ((NHC)-N-Dipp = bis(2,6-diisopropylphenyl)imidazol-2-ylidene) possessing an unsaturated NHC backbone both react with HgCl2 to give the bis(carbenephosphinidenyl) complexes [((NHC star)-N-Dipp=P)(2)Hg] and [((NHC)-N-Dipp=P)(2)Hg].