- Synthesis, structures and reactivity of 2-phosphorylmethyl-1H-pyrrolato complexes of titanium, yttrium and zinc
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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(NMe 2)4 affords octahedral Ti(NMe2) 2{NC4H2(4-R′)CH2P(O)R 2}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(SiHMe 2)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 Y{N(SiHMe2)2}{NC 4H3(5-But)CH2P(O)Ph 2}2 which shows good activity for the ring-opening polymerisation of cyclic esters. The Royal Society of Chemistry 2009.
- Broomfield, Lewis M.,Wright, Joseph A.,Bochmann, Manfred
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experimental part
p. 8269 - 8279
(2010/03/04)
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