Inter- and intramolecular thermal activation of aliphatic C-H bonds mediated by complexes containing the fragments [{Cy2P(CH2)nPCy2}M] (n = 1-4, M = Rh, Ru)

Article abstract of DOI:10.1002/cber.19971300504

A well defined geometrical structure and a well established catalytic potential for a plethora of processes puts the chelate rings [{R₂P(CH₂)_nPR₂)M] (M = Rh, Ru) among the most interesting candidates for catalytic alkane functionalization in homogeneous solution. It is demonstrated that intermolecular thermal C-H activation (3 → 4) is possible with readily accessible complexes [{Cy₂P(CH₂)_nPCy₂}Rh(hfacac)] (n = 1-4, 1a-c) and [{Cy₂P(CH₂)_nPCy₂)Ru(η ³-C₄H₇)₂] (n = 1-3, 2a-c) containing such fragments. A maximum of 5 catalytic cycles was achieved with complex 2a. In case of Ru complexes containing the same ligands with n = 3 and 4, intramolecular cleavage of three adjacent C- H bonds in one of the cyclohexyl substituents at phosphorus also occurs readily leading to formation of a new polydentate κ²P,P′,η³-allyl ligand. VCH Verlagsgcsellschaft mbH,.