Novel p-cymene-osmium(<scp>II</scp>) and -osmium(0) complexes: a ring ligand determining inter-vs. intra-molecular C–H addition
作者:Helmut Werner、Karin Zenkert
DOI:10.1039/c39850001607
日期:——
The osmium(0) complex [(pc)Os(C2H4)PMe3][pc =η6-p-cymene (4-isoproltoluene)](7) has been prepared together with a group of neutral and cationic p-cymemeosmium(II) compounds; in contrast to [C6H6Os(C2H4)PMe3], the corresponding p-cymene complex (7) reacts with an excess of PM3 in benzene not by intra- but by inter-molecular C–Haddition to form [OsH(C6H5)(PMe3)4].
锇(0)配合物[(PC)锇(C 2 H ^ 4)PME 3 ] [PC =η 6 - p -cymene(4- isoproltoluene)](7)已经被与一组中性和阳离子的制备一起p -cymemeosmium(II)化合物;与[C 6 H 6 Os(C 2 H 4)PMe 3 ]相比,相应的对-Cymene配合物(7)与苯中过量的PM 3反应不是通过分子内而是通过分子间C–H加成形成[OsH(C 6 H 5)(PMe 3)4 ]。
Enthalpies of Reaction of [(<i>p</i>-cymene)OsCl<sub>2</sub>]<sub>2</sub> with Monodentate Tertiary Phosphine Ligands. Importance of Steric and Electronic Ligand Factors in an Osmium(II) System
作者:Jinkun Huang、Scafford Serron、Steven P. Nolan
DOI:10.1021/om980345e
日期:1998.8.1
The enthalpies of reaction of [OsCl2(p-cymene)](2) (1) (p-cymene = eta(6)-CH3C6H4CH(CH3)(2)) with a series of monodentate phosphines (PR3), leading to the formation of OsCl2(p-cymene)(PR3) complexes, have been measured by anaerobic calorimetry in CH2Cl2 at 30 degrees C. These reactions are rapid and quantitative. The overall relative order of stability established is as follows: PPh(NC4H4)(2) < P(NC4H4)(3) < P(p-CF3C6H4)(3) < PPh2(NC4H4) < PPh3 < P(p-ClC6H4)(3) < P(p-CH3C6H4)(3) < P(p-FC6H4)(3) < PCy3 < PBz(3) < (PPr3)-Pr-i < P(p-CH3OC6H4)(3) < P(NC4H8)(3) < PPh2Me < PPhMe2 < PEt3 < PMe3. A quantitative analysis of ligand effects for the present data helps clarify the exact steric versus electronic ligand contributions to the enthalpy of reaction in this system. Both steric and electronic factors appear to play an important role in dictating the magnitude of the enthalpy of reaction. The data are compared to the previously studied RuCl2(p-cymene)(PR3) system.
Mononuclear η<sup>6</sup>-p-cymeneosmium(<scp>II</scp>) complexes and their reactions with Al<sub>2</sub>Me<sub>6</sub>and other methylating reagents