ChemInform Abstract: CO Labilization and Hydrogen‐Transfer Pathways in Cationic Phosphido‐Bridged Re‐Pt Heterobimetallic Systems and the Molecular Structures of (η5‐Cp(ON)Re(μ‐PR2)(μ‐H)Pt(PPh3)2)X (R: Cy, X‐: PF‐ 6; R: Ph, X‐: BF‐ 4) and Cyclic (η5‐Cp(ON)HRe(μ‐PCy2)Pt(PPh3)2)BF4, a Rare Example of Bridging‐ and Terminal‐Hydrido Geometric Isomers.

Abstract

ChemInform Abstract The reaction of the cationic sec. phosphine complexes (I) with Pt(PPh3)4 (II) leads to CO loss and the formation of the terminal Re hydride derivative (III) ((IIIb): space group P21/n, Z=4) as the kinetic product. On standing, (III) slowly transforms into the thermodynamically preferred bridging-hydrido isomer (IV) ((IVa), (IVb): for both P1, Z=2). However, the oxidative addition of (Ib) and (Ic) to the ethylene-Pt(II) complex (V) gives the complexes (VI). The cations (VI) will undergo slow CO loss to form (III) in the presence of base and the isomerization of (III) to (IV) is promoted by added chloride ion. The mechanism of formation of (III) and (VI) from (I) and the mechanism of the base-promoted (VI) to (III) rearrangement and the Cl-catalyzed (III) to (IV) isomerization process are discussed.