Synthesis of neutral and zwitterionic phosphinomethylpyrrolato complexes of nickel
作者:Lewis M. Broomfield、David Boschert、Joseph A. Wright、David L. Hughes、Manfred Bochmann
DOI:10.1016/j.jorganchem.2009.08.033
日期:2009.12
Potassium salts of the new 2-phosphinomethyl-1H-pyrroles, K[R2PCH2C4H3N] (R = Ph, Cy) react with (η3-allyl)nickel bromide to give the chelate complexes (R2PCH2C4H3N)Ni(allyl), whereas the stericallyhindered 2-diphenylphosphinomethyl-5-t-butyl-1H-pyrrole and (η3-allyl)nickel bromide afford a phosphine adduct (HNC4H2-5-But-2-CH2PPh2)Ni(allyl)Br which is stabilized by an intramolecular NH⋯Br hydrogen
Synthesis, structures and reactivity of 2-phosphorylmethyl-1H-pyrrolato complexes of titanium, yttrium and zinc
作者:Lewis M. Broomfield、Joseph A. Wright、Manfred Bochmann
DOI:10.1039/b908394d
日期:——
The reaction of secondary phosphines HPR2 (R = Ph, Cy) with pyrrole-2-aldehydes gives a new family of 2-phosphorylmethyl-1H-pyrroles as potentially chelating mono-anionic ligands. The reaction with Ti(NMe2)4 affords octahedral Ti(NMe2)2NC4H2(4-R′)CH2P(O)R2}2 (R′ = H, But). While the diphenylphosphoryl complexes adopt a configuration with trans-pyrrolato ligands, the dicyclohexyl analogue prefers an all-cis conformation, with profound consequences on metal–ligand bonding. The reaction of sterically undemanding HNC4H3CH2P(O)Ph2 with Y[N(SiHMe2)2]3(THF)2 give the homoleptic complex Y[NC4H3CH2P(O)Ph2]3; mixed-ligand intermediates Y[N(SiHMe2)2]2(N–O) and Y[N(SiHMe2)2](N–O)2 were identifiable but could not be isolated. The bulky ligand HNC4H2(5-But)CH2P(O)Ph2 does not react with Ti(NMe2)4 but protolyses Zn[N(SiMe3)2]2 to give a 1 : 2 complex Zn(N–O)2 as the only isolable product. On the other hand, its reaction with Y[N(SiHMe2)2]3(THF)2 affords the mono-amido complex YN(SiHMe2)2}NC4H3(5-But)CH2P(O)Ph2}2 which shows good activity for the ring-opening polymerisation of cyclic esters.