Arene displacement, C-H activation and acetonitrile insertion reactions enabled by coordination of a functionalized iminophosphorane to a Ru--cymene scaffold.

Reaction of a sterically demanding iminophosphorano-phosphine, PhPCHPhPNAr* (here onwards referred to as PCPNAr*; Ar* = 2,6-dibenzhydryl-4-methylphenyl), (1) with [Ru(η--cymene)Cl] yielded three different types of complex, [RuCl{(η--cymene)(PCPNAr*)-κ-}] (2), [RuCl{(P(O)CPNAr*)(κ-,)(-η-arene)}] (3) and [RuCl{(POCPNAr*)(κ-,)(-η-arene)}] (4), depending on the reaction conditions CH activation, tethered η-arene coordination, -metallation or PN bond cleavage/rearrangement reactions. Interestingly, a similar reaction in CHCN in the presence of AgBF resulted in the insertion of CHCN into the PN bond to form a novel metallacycle [Ru(NCMe){(PCPN(CH)CNAr*)-κ-,,}][BF] (5) containing 4- and 5-membered rings an aza-Wittig type reaction. Complex 4 showed very good catalytic activity in the transfer hydrogenation of carbonyl compounds.