Ruthenium(III) complexes containing bi- and tridentate phosphorus−nitrogen ligands

Abstract

Air-stable RuIII complexes containing a bidentate aminophosphine ligand (PN) of the type mer-RuCl3(PN)(PR3) are made from the precursors RuCl3(PR3)2(DMA)·DMA (PN = o-diphenylphosphino-N,N′-dimethylaniline (P−N) and (R)-N,N′-dimethyl-1-[o-diphenylphosphinophenyl]ethylamine ((R)-AMPHOS); R = Ph, p-tolyl; DMA = N,N′-dimethylacetamide). With the tridentate bis[o-(N,N′-dimethylamino)phenyl]phenylphosphine (BNP), the product is mer-RuCl3(BNP) (3), while tris[o-(N,N′-dimethylaminophenyl)phosphine (TNP) is unreactive toward the precursor. Crystal structures of mer-RuCl3(PN)(PPh3), where PN is P−N (2a), (R)-AMPHOS (4a), and 3·CHCl3 are reported as well as those of (R)-AMPHOS, BNP, and TNP. The RuIII−aminophosphine complexes are the first monomeric RuIII species to be formed via the useful, easily synthesized, air-stable RuIII precursors RuCl3(PR3)2(DMA)·DMA (1a and 1b); complex 2a is formed also via reaction of HCl with trans-RuCl2(P−N)(PPh3). A crystal structure of mer,cis-RuCl3(DMA)2(PPh3)·DMA (1c), a side-product from the synthesis of the RuIII precursor, is also presented and is the first-reported complex of DMA with RuIII. Preliminary data show that the RuIII−aminophosphine complexes in DMA (a proton-accepting solvent) are reduced by H2 to RuII species that can react further to form an η2-H2 adduct and then a RuII-hydridochloro species.