TY - JOUR
T1 - Synthesis and reactivities of lanthanide-ylidic complexes
AU - WONG, Rick W K
AU - Chen, Hua
AU - Chow, Fong Lung
N1 - Funding Information:
Acknowledgements-We thank the CroucherF oundation and the Hong Kong Polytechnicf or financial support.
PY - 1990
Y1 - 1990
N2 - The reaction of [Li(Et2O)2][Cp′2MCl2] (Cp′ = C5Me5; M = Nd, Sm) with 1 equivalent of Li(CH2)(CH2)PRR′(a, R = Me, R′ = Ph; b, R = R′= Ph; c, R = R′= Me; d, R = R′ = t-Bu) produces Cp′2M[(CH2)(CH2)PPR′]·(LiCl)2 (I, M = Sm; II, M = Nd) in moderate yield. Variable-temperature 1H NMR studies on Cp′2M[(CH2)(CH2)P(Me)R]·(LiCl)2 (M = Nd, Sm; R = Me, Ph) show that the methyl protons on the phosphorus of the chelating ylide undergo rapid exchange with the bridging methylene protons even at -40°C. A mechanism which is based on a series of metal-carbon bond breaking, rotation and recombination processes has been proposed for the fluxional behaviour. The ylidic complexes react with hydrogen (1 atm) at ambient temperature producing C5Me5H and the corresponding phosphonium salts, [RR′PMe2]Cl. 1H NMR studies on the reactivity of Ia towards hydrogen and acid review that the metal-carbon bond formed between the lanthanide metal and the chelating phosphorus ylide is more stable than that formed between the lanthanide metal and the pentamethylcyclopentadienyl ring.
AB - The reaction of [Li(Et2O)2][Cp′2MCl2] (Cp′ = C5Me5; M = Nd, Sm) with 1 equivalent of Li(CH2)(CH2)PRR′(a, R = Me, R′ = Ph; b, R = R′= Ph; c, R = R′= Me; d, R = R′ = t-Bu) produces Cp′2M[(CH2)(CH2)PPR′]·(LiCl)2 (I, M = Sm; II, M = Nd) in moderate yield. Variable-temperature 1H NMR studies on Cp′2M[(CH2)(CH2)P(Me)R]·(LiCl)2 (M = Nd, Sm; R = Me, Ph) show that the methyl protons on the phosphorus of the chelating ylide undergo rapid exchange with the bridging methylene protons even at -40°C. A mechanism which is based on a series of metal-carbon bond breaking, rotation and recombination processes has been proposed for the fluxional behaviour. The ylidic complexes react with hydrogen (1 atm) at ambient temperature producing C5Me5H and the corresponding phosphonium salts, [RR′PMe2]Cl. 1H NMR studies on the reactivity of Ia towards hydrogen and acid review that the metal-carbon bond formed between the lanthanide metal and the chelating phosphorus ylide is more stable than that formed between the lanthanide metal and the pentamethylcyclopentadienyl ring.
UR - http://www.scopus.com/inward/record.url?scp=0041025072&partnerID=8YFLogxK
U2 - 10.1016/S0277-5387(00)81354-6
DO - 10.1016/S0277-5387(00)81354-6
M3 - Journal article
AN - SCOPUS:0041025072
SN - 0277-5387
VL - 9
SP - 875
EP - 879
JO - Polyhedron
JF - Polyhedron
IS - 6
ER -