86822-14-2Relevant academic research and scientific papers
Synthetic, Structural, and Theoretical Studies of η2-Acyl Complexes of Molybdenum
Curtis, M. David,Shiu, Kom-Bei,Butler, William M.
, p. 1550 - 1561 (1986)
Hydridotris(pyrazolyl)borate (Tp) complexes of the type TpMo(CO)2(η2-COR) (R = Me (1), Ph (2) are formed from the reaction of TpMo(CO)3- with MeI, Me3O+, MeCOBr, or PhCOBr.The use of 13C-labeled PhC*OBr in the reaction established that a carbonyl initially on the metal is lost in the decarbonylation and that the η2-acyl is not in equilibrium with a low concentration of the isomeric ?-alkyltricarbonyl complex.The derivatives Tp(CO)LMo(η2-COMe) (L = P(OMe)3 (3) and PEt3 (4) are made from 1 and the appropiate phosphine.The structures of 1-4 were determined by X-ray crystallography: (1) a, b, and c = 8.995(3), 12.803(4), and 14.999(6) Angstroem; β = 103.98(3) deg; V = 1677(1) Angstroem3; z = 4; space group P21/n (no. 14); (2) a, b, and c = 9.405(2), 12.505(3), and 9.025(2) Angstroem; α,β, and γ = 114.59(2), 92.85(2), and 95.45(2) deg; V = 956.0(4) Angstroem3; Z = 2; space group = P1/ (no. 2); (3) a, b, and c = 8.953(2), 15.684(6), and 8.032(4) Angstroem; α,β, and γ = 99.47(4), 102.79(3), and 97.78(3) deg; V = 1067.5(7) Angstroem3; Z = 2; space group = P1/.Values of R1 and R2 for 1-4 are 0.045, 0.059 (1); 0.038, 0.063 (2); 0.038, 0.056 (3); and 0.44, 0.061 (4).The bonding of an L5M(d4) fragment to the η2-acyl group, the rotational conformations of the latter, and the realative stabilities of Cp(CO)2Mo(η2-HCO),Cp(CO)3Mo-H, (N-donor)3(CO)2Mo(η2-HCO), and (N-donor)3(CO)3Mo-H are comprehensively treated within the framework of the Extended Hueckel MO formalism.It is shown that there is substantial double-bond character in the Mo=C(acyl) bond but a very weak Mo-O bond and that the compounds should be regarded as stabilized 16-electron complexes.There is an inherent tendency toward a bending distortion in the L5M fragment, and η2-acyl group tends to be aligned with the axis of distortion and/or with the M-CO bond(s).
Sterically induced η2-acyl formation: Syntheses and structures of TpMo(CO)2(η2-COR) (R = Me, Ph) and TpMo(CO)3Br (Tp = hydridotris(pyrazolyl)borate)
Curtis, M. David,Shiu, Kom-Bel,Butler, William M.
, p. 1475 - 1477 (2008/10/08)
The anion TpMo(CO)3- (Tp = hydridotris(pyrazolyl)borate) reacts with MeI or Me3OBF4 or with PhCOBr to give the η2-acyl complexes TpMo(CO)2(η2-COR) (R = Me, Ph). These facile alkyl migration and decarbonylation reactions are ascribed in part to the steric demands of the Tp ligand, which are evident in the structure of TpMo(CO)3Br, and in part to the electronic tendency of the Tp ligand to favor an octahedral coordination geometry.
