Reactions of (PMe3)4Ru(C2H4) and (DMPE)2Ru(C2H4) with weak proton-donating electrophiles HX (X = OAr, SAr, NHPh, PHPh). Synthesis of complexes with metal-heteroatom single bonds

Article abstract of DOI:10.1021/om00001a023

Reactions of the ruthenium ethylene complexes (PMe₃)₄Ru(C₂H₄) and (DMPE)₂Ru(C₂H₄) with a variety of HX compounds (X = SAr, OAr, PPhH, NHPh and Ph) have been explored. In all cases, the tetrakis(trimethylphosphine) complex reacted to form ethylene and the hydrido species, (PMe₃)₄Ru(H)(X). However, parallel studies with the related material (DMPE)₂Ru(C₂H₄) suggest that these complexes react as strained metallacycles toward HX. Thus, the bis(DMPE) analog gave the ethyl species (DMPE)₂Ru(X)(CH₂CH₃) in its reactions with HSAr and PH₂Ph, and thermolysis of these ethyl complexes led to the formation of the hydrides and free ethylene. The reaction of the DMPE ethylene complex with p-cresol allowed isolation of an intermediate cationic ethylene hydride species, but this was converted rapidly to the corresponding aryloxy hydride complex, even at room temperature. With NH₂Ph the bis(DMPE) complex formed only the corresponding hydride species. In an attempt to generate an acetylene complex that similarly might react as a strained metallacyclopropene, (PMe₃)₄Ru(CH=CH₂)₂ was generated from the reaction of CH=CH₂MgBr with (PMe₃)₄RuCl₂. However, thermolysis of the divinyl species led only to the formation of the butadiene complex, (PMe₃)₃Ru(C₄H₆).