Dicationic Alkylidene-, Olefin-, and Alkoxyalkenylcarbene-Osmium Complexes Stabilized by a NHC-Ligand
Autores: Maria L. Buil, Ricardo Castarlenas, Miguel A. Esteruelas, Susana Izquierdo, Ralte Lalrempuia y Enrique Oñate
Ref. revista: Organometallics, 29, 876-882 (2010)
Complex [Os(dCHPh)(CH3CN)4(IPr)](OTf)2 (1) (IPr=1,3-bis(2,6-diisopropylphenyl)imidazolylidene; OTf=CF3SO3) exchanges the alkylidene group with propylene to give styrene and [Os(dCHCH3)(CH3CN)4(IPr)](OTf)2 (2). The reaction of 1 with ethylene leads to [Os(η2-CH2dCH2)(CH3CN)4(IPr)](OTf)2 (3) via the propylene intermediate [Os(η2-CH2dCHCH3)(CH3CN)4(IPr)]-
(OTf)2 (4). Acetonitrile displaces the olefin ligand of both 3 and 4 to generate the pentakis(solvento) derivative [Os(CH3CN)5(IPr)](OTf)2 (5). In 2-propanol and methanol, complex 5 reacts with 1,1-diphenyl-2-propyn-1-ol and 2-methyl-3-butyn-2-ol to yield the corresponding alkoxyalkenylcarbene compounds [Os{dC(OR)CHdCR0
2}(CH3CN)4(IPr)](OTf)2 (R=CH(CH3)2; R0=Ph (6), CH3 (7);R=CH3; R0=Ph (8), CH3 (9)). The X-ray structures of 4, 5, and 6 are also reported.
Complex [Os(dCHPh)(CH3CN)4(IPr)](OTf)2 (1) (IPr=1,3-bis(2,6-diisopropylphenyl)imidazolylidene; OTf=CF3SO3) exchanges the alkylidene group with propylene to give styrene and [Os(dCHCH3)(CH3CN)4(IPr)](OTf)2 (2). The reaction of 1 with ethylene leads to [Os(η2-CH2dCH2)(CH3CN)4(IPr)](OTf)2 (3) via the propylene intermediate [Os(η2-CH2dCHCH3)(CH3CN)4(IPr)]-
(OTf)2 (4). Acetonitrile displaces the olefin ligand of both 3 and 4 to generate the pentakis(solvento) derivative [Os(CH3CN)5(IPr)](OTf)2 (5). In 2-propanol and methanol, complex 5 reacts with 1,1-diphenyl-2-propyn-1-ol and 2-methyl-3-butyn-2-ol to yield the corresponding alkoxyalkenylcarbene compounds [Os{dC(OR)CHdCR0
2}(CH3CN)4(IPr)](OTf)2 (R=CH(CH3)2; R0=Ph (6), CH3 (7);R=CH3; R0=Ph (8), CH3 (9)). The X-ray structures of 4, 5, and 6 are also reported.