Thermal Dimerization of 3,4-Dimethyl-1-Phenylphosphole within the Coordination Sphere of [(η6-Arene)Ru(DMPP)2Cl]PF6 Complexes

Thermolysis of a 1,2-dichloroethane solution containing a 1:1.5:1 molar ratio of (η6-C6Me6)Ru(DMPP)Cl2, DMPP, and NaPF6 produced [(η6-C6Me6)Ru(DMPP)2Cl]PF6 (1), [(η6-C6Me6)Ru(DMPP)2[4+4]Cl]PF6 containing an unprecedented [4+4] DMPP cyclodimer (2), [(η6-C6Me6)Ru(DMPP)2[4+2]CI]PF6 containing a [4+2] Diels−Alder dimer of DMPP (3), and (η6-C6Me6)Ru(3-methyl-4-methylene-1-phenyl-2-phospholene)C12 (4) that results from an allylic [1,3]-hydrogen shift. Thermolysis of a 1,2-dichloroethane solution containing a 1:1.5:1 molar ratio of (η6-p-MeC6H4CHMe2)Ru(DMPP)Cl2, DMPP, and NaPF6 produced [(η6-p-MeC6H4CHMe2)Ru(μ-Cl)3Ru(DMPP)2[4+2](DMPP)]PF6 (5), containing a Diels−Alder [4+2] DMPP dimer, and [(DMPP)3Ru(μ-Cl)3Ru(DMPP)3]PF6 (6). All these complexes have been characterized by elemental analyses, physical properties, infrared spectroscopy, cyclic voltammetry, X-ray crystallography, and 1H, 1H{31P}, 13C{1H}, and 31P{1H} NMR spectroscopy.