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Rhodium(I), Palladium(II), and Platinum(II) Complexes Containing New Mixed Phosphane−Phosphite Ligands − Effect of the Catalytic System Stability on the Enantioselective Hydroformylation of Styrene
Author(s) -
Arena Carmela G.,
Faraone Felice,
Graiff Claudia,
Tiripicchio Antonio
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200203)2002:3<711::aid-ejic711>3.0.co;2-e
Subject(s) - chemistry , rhodium , hydroformylation , palladium , chelation , catalysis , ligand (biochemistry) , styrene , medicinal chemistry , trimethylsilyl , enantioselective synthesis , triphenyl phosphite , denticity , polymer chemistry , crystal structure , organic chemistry , copolymer , polymer , biochemistry , receptor
The new mixed phosphane−phosphite ligands 1 and 2 , derived from 3,3′‐di‐ tert ‐butyl‐2,2′‐dihydroxy‐5,5′‐dimethoxybiphenyl and ( S )‐binaphthol, respectively, reacted with [Rh(COD)(THF) 2 ]CF 3 SO 3 to give the compounds [Rh(COD)( 1 )]CF 3 SO 3 and [Rh(COD)( 2 )]CF 3 SO 3 in which the ligands 1 and ( S )‐ 2 are chelated to the rhodium centre. The reaction with [Rh(CO) 2 Cl] 2 gave two different products, [Rh(CO) 2 (L)Cl] and [Rh(CO)(L)Cl] [L = 1 and ( S )‐ 2 ], containing L as a chelate. On the basis of the IR and NMR spectroscopic data, the proposed structure of the pentacoordinate species is a trigonal bipyramide in which the phosphane−phosphite ligand assumes an equatorial‐axial coordination. The reactions of 1 and 2 with [Pd(C 6 H 5 CN) 2 Cl 2 ] and [Pt(COD)I 2 ] gave the corresponding compounds [Pd(L)Cl 2 ] and [Pt(L)I 2 ] in which the ligands are chelated to the metal centre. The crystal structure of the chloroform solvate of [Pd(L)Cl 2 ] was fully characterised by an X‐ray study. The chiral ligands ( S )‐ 2 and ( S )‐ 3 [derived from the ortho ‐bis(trimethylsilyl)‐substituted ( S )‐binaphthol] were tested in the hydroformylation of styrene. The results obtained were discussed in light of the catalytic system stability.