Steric effects induced by ferrocenyl in tertiary organophosphines: crystalstructure of trans-chloromethylbis(ferrocenyldiphenylphosphine)palladium (II) benzene disolvate

The structure determination of the title compound, trans-[PdMeCl(PPh(2)Fc)( 2)]. 2C(6)H(6), (PPh(2)Fc = C22H19FeP) shows the Pd(II) moiety to have a sq uare planar geometry with the bulky phosphine ligands in a trans orientatio n. The compound crystallises in the triclinic space group P (1) over bar wi th 1 mole per unit cell accompanied by two benzene solvent molecules. A 50% statistical disorder was observed in the methyl and chloride positions. Bo nd distances and angles of the coordination polyhedron are Pd-P = 2.3328(10 ) Angstrom, Pd-Cl = 2.378(3) Angstrom, Pd-C(10) = 2.108(10) Angstrom, P-Pd- Cl = 92.70(9)degrees and P-Pd-C(10) = 86.8(4)degrees. The structure is comp ared with the isomorphous trans-[Pt(Cl)(2)(PPh(2)Fc)(2)]. 2C(6)H(6) and oth er relevant structures of Pt(II) and Pd(II) described in the literature. Th e steric demand of the PPh(2)Fc ligand was estimated from all known structu res to be approximately 155 degrees using the Tolman model. (C) 2000 Elsevi er Science S.A. All rights reserved.