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Metal Complexes of Biologically Important Ligands, CLXXV [1]. Pentamethylcyclopentadienyl Halfsandwich Complexes of Rhodium(III) and Iridium(III) with Schiff Bases from 2-(Diphenylphosphino)- benzaldehyde and α-Amino Acid Esters

2010; De Gruyter; Volume: 65; Issue: 6 Linguagem: Inglês

10.1515/znb-2010-0603

1865-7117

B. Schreiner, Barbara Wagner-Schuh, Wolfgang Beck,

Asymmetric Hydrogenation and Catalysis

The reactions of the chlorido-bridged complexes [Cp*M(Cl)(μ-Cl)] 2 (M = Rh, Ir) with Schiff bases (P-N-O) from 2-(diphenylphosphino)benzaldehyde and α-amino acid esters afford the complexes Cp*M(Cl) 2 (P-N-O) in which the ligands function as monodentate P donors (M = Ir) or as bidentate P-N donors (M = Rh). These complexes can be converted into cationic complexes [Cp*M(Cl)(P-NO)] + with bidentate P-N ligands by treatment with NH4PF6. The cationic complexes [Cp*M(Cl)(PN- O)] + Cl − have been detected also in solutions of Cp*M(Cl) 2 (P-N-O). The P-N-coordinated complex [Cp*Rh(Cl)(Ph 2 P-C 6 H 4 -C(H)=N-C(H)(CH 2 Ph)CO 2 Me)] + PF 6 − was characterized by X-ray diffraction. From Cp*M(Cl) 2 (P-N-O) and AgBF 4 or AgPF 6 (molar ratio 1 : 2) the dicationic complexes [Cp*M(P-N-O)] 2+ are formed in which the ester group is also coordinated to the metal atom. The Schiff base from 2-(diphenylphosphino)benzaldehyde and allylglycine ester acts as a tridentate ligand, however with coordination of the C=C allyl group instead of the ester function.