The chemistry of three-coordinate nickel phosphinidene, imido, and carbene complexes

The cationic phosphide complex [(dtbpe)Ni(PHdmp)][PF 6] can be deprotonated to afford the first monomeric, Group 10 phosphinidene complex (dtbpe)Ni=P(dmp) (6). The chemistry of 6 is abundant. "PR"-group transfer from 6 is effected to ethylene, alkynes, and CO to provide the phosphirane, unsaturated phosphirene, and phosphaketene products. These reactions appear to proceed via a [2+2] cycloaddition intermediate followed by reductive elimination of product. Complex 6 undergoes [2+2] cycloaddition with CS2 and PhC=C=O. Phosphinidene 6 is selectively protonated at the phosphinidene phosphorus.; A general route to three-coordinate and related four-coordinate nickel imido complexes (dtbpe)Ni=NR (R=aryl, alkyl) and (dtbpe)Ni{lcub}N,O:eta 2-NC(O)R{rcub} has been established. Treating [(dtbpe)Ni]2(eta 2,mu-C6H6) (31) with N3 R gives hereto unknown eta2-bound organic azide adducts, (dtbpe)Ni(eta2-N3R), which thermally liberate N2 and form imido species. Kinetic studies show thermolysis is a pseudo-first-order reaction in (dtbpe)Ni(eta2-N3R), but a pre-equilibrium with free N3R requires an added quantity of 31 for clean conversion to imido products. Ni-imido complexes undergo [2+2] cycloaddition, protonation, and group transfer reactions. The first example of an isolated imido complex undergoing aziridination is also documented. Aziridine and phosphirane formation proceeds with net retention of relative stereochemistry as demonstrated by a labeling study with trans-ethylene-d2.; (dtbpe)Ni=CPh2 (61) transfers a carbene fragment to olefins and alkynes to give cyclopropane and cyclopropene products. Cyclopropanation with 53 proceeds with net retention of relative stereochemistry, determined by reaction with trans-1-deutereo-1-hexene. 31 forms adducts with olefins and alkynes, the nickel products of group transfer reactions. 61 activates chalcogenides and reduces water and ammonia to H2 providing (dtbpe)Ni(ECPh2) (E = O, S, Se, Te, NH).; The cationic cyclopentadienyl complexes [(dtbpe)Ni(eta5-C 5HR4)] [PF6], prepared by oxidation of related nickel(I) species, react with Bronsted bases to afford exclusively metallacycle products. Nickel(I) silyl and germyl complexes with bulky aryl substituents have been synthesized using salt metathesis with [(dtbpe)NiCl] 2. The cationic germylene hydride complex [(dtbpe)Ni(H)=GeMes2 ] [B(C6F5)4] is prepared by oxidatively induced alpha-hydride migration of [(dtbpe)Ni(GeHMes2)]. Using a tertiary germyl ligand provides the germyl cation [(dtbpe)Ni(GePh3 )][B(C6F5)4] upon oxidation.; Related dtbpe-supported Pt-amide and -phosphide compounds have been prepared in attempts to prepare imido and phosphinidene species. An examination of related dtbpe-and beta-diketiminate-supported copper chemistry is presented.