名称:
Rhodium(
I
), Palladium(
II
) and Platinum(
II
) Coordination Chemistry of the Short‐Bite Chiral Ligands (
S
c
)‐
N
,
N
‐Bis(diphenylphosphanyl)‐
sec
‐butylamine, (
R
a
,
R
a
)‐
N
,
N
‐Bis(binaphthylphosphonito)phenylamine and (
R
a
,
S
c
)‐
N
‐(Diphenylphosphanyl)‐
N
‐(binaphthylphosphonito)‐
sec
‐butylamine
摘要:
AbstractThe new short‐bite chiral ligands (Sc)‐N,N‐bis(diphenylphosphanyl)‐sec‐butylamine [(Sc)‐1], (Ra,Ra)‐N,N‐bis(binaphthylphosphonito)phenylamine [(Ra,Ra)‐2] and (Ra,Sc)‐N‐(diphenylphosphanyl)‐N‐(binaphthylphosphonito)‐sec‐butylamine [(Ra,Sc)‐3] have been treated with rhodium(I), palladium(II) and platinum(II) substrates. The (Sc)‐1 ligand reacts with [Pd(C6H5CN)2Cl2], [Pt(COD)Cl2] and [Rh(COD)(THF)2]PF6 to afford the products [Pd(Sc‐1)Cl2] (4), [Pt(Sc‐1)Cl2] (5) and [Rh(COD)(Sc‐1)]PF6 (6), respectively, in high yields. By bubbling CO to a CH2Cl2 solution of 6, we formed the dicarbonyl species [Rh(CO)2(Sc‐1)]PF6 (7), which is stable only in solution under CO. Compounds 4 and 5 were characterized additionally by X‐ray diffraction studies. The ligand (Ra,Ra)‐2 reacts with [Pd(C6H5CN)2Cl2] and [Pt(COD)I2] to give [Pd(Ra,Ra‐2)Cl2] (8) and [Pt(Ra,Ra‐2)I2] (9), respectively; the reaction with [Rh(CO)2Cl]2 or [Rh(COD)(THF)2]PF6 affords a mixture of mono‐ and binuclear compounds, in which the ligand is oxidized to the corresponding phosphonate or is partially hydrolysed. The compounds [Pd(Ra,Sc‐3)Cl2] (10) and [Pt(Ra,Sc‐3)I2] (11) were obtained in the analogous reactions using the asymmetric (Ra,Sc)‐3 ligand. This ligand reacted with [Rh(CO)2Cl]2 in a 2:1 molar ratio in hexane to give a mixture of products in almost equal amounts. The 31P{1H} NMR spectrum recorded in CDCl3 allowed us to identify the chelate [Rh(Ra,Sc‐3)(CO)Cl] (12); the nature of the accompanying dinuclear species 13 is not clear. The catalytic systems formed by [Rh(acac)(CO)2] and the ligands (Ra,Ra)‐2 and (Ra,Sc)‐3, at ligand/metal ratios of 1:1 and 1:2, were unstable under the experimental conditions used (CO/H2 pressure of 50 atm and temperature of 40 °C) for the hydroformylation of styrene; instead, metallic rhodium was afforded together with unidentified decomposition products. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)