名称:
Reaction of Rh2(μ2-O2CCH3)3[μ2-(C6H4)PMePh](HO2CCH3)2 with triphenylphosphine: rearrangement of the metalated PMePh2 ligand and formation of a compound with a diphenylphosphinomethanide group in (P,C) coordination; crystal structure of [Rh2(μ2-O2CCH3)2{μ2-(CH2)PPh2}- {μ2-(C6H4)PPh2}(PPh3)]·2CH2Cl2
摘要:
The reaction of [Rh-2(mu(2)-O2CCH3)(3){mu(2)-(C6H4)PMePh}] (1) in CHCl3 with one mole of PPh(3) gives the two phosphine monoadducts, which are in rapid equilibrium above -40 degrees C. After 6 h at room temperature this mixture gives [Rh-2(mu(2)-O2CCH3)(2){mu(2)-(C6H4)PMePh}{mu(2)-(C6H4)PPh(2)}](HO2CCH3)(2) (3), a doubly metalated compound with a head-to-head configuration. 1 reacts with two moles of PPh(3), forming the bis-adduct 1.P-2, which at 10 degrees C gives a mixture of 3, in the form of its phosphine adduct 3.P, and [Rh-2(mu(2)-O2CCH3)(2){mu(2)-(CH2)PPh(2)}{mu(2)-(C6H4)PPh(2)}(PPh(3))] (2). It is confirmed that 3.P is not the kinetic product in the reaction from 1.P-2 to 2. The structure of [Rh-2(mu(2)-O2CCH3)(2){mu(2)-(CH2)PPh(2)}{mu(2)-(C6H4)PPh(2)}(PPh(3))]. 2CH(2)Cl(2) has been determined by X-ray diffraction: M(r)=1216.55, monoclinic, space group P2(1)/c, a=19.930(8), b=15.29(2), c=16.84(2) Angstrom, beta=90.14(9)degrees, V=5129(9) Angstrom(3), Z=4, D-c=1.58 g cm(-3), Mo K alpha radiation (graphite monochromator, lambda=0.71073 Angstrom), mu (Mo K alpha)=9.80 cm(-1), F(000)=2464, T=200 K. The final conventional R factor was 0.061 for 4749 'observed' reflections. The compound contains an orthometalated triphenylphosphine and a diphenylphosphinomethanide group bridging the two rhodium atoms. The two ligands are in a head-to-head configuration. Two bridging acetate groups and one axial PPh(3) complete the coordination around the rhodium atoms. The Rh-Rh bond distance is 2.532(2) Angstrom.