title: Facile ligand oxidation and ring nitration in ruthenium complexes derived from a ligand with dicarboxamide-N and phosphine-P donors.
abstract: The reaction of the tetradentate dicarboxamide ligand 1,2-bis-N-[2'(diphenylphosphanyl)benzoyl]diaminobenzene (dppbH(2)) with RuCl(3) in DMF or ethanol results in metal-mediated ligand oxidation and formation of the diamagnetic Ru(II) complex [(dppQ)Ru(Cl)(2)] (1) with N(2)P(2) chromophore. The o-phenylenedicarboxamide portion of the dppb(2-) ligand is oxidized to a o-benzoquinonediimine (bqdi) moiety in [(dppQ)Ru(Cl)(2)]. Presence of oxygen accelerates the ligand oxidation process. Unlike other tetradentate dicarboxamide ligands with pyridine-N, phenolato-O, or thiolato-S donors, dppb(2-) provides stability to the +2 oxidation state of ruthenium and facilitates oxidation of the coordinated ligand frame. Results of spectroscopic and redox studies strongly support the +2 oxidation state of Ru in 1. Exposure of 1 to NO(g) does not lead to formation of any metal nitrosyl; instead, the bqdi ring is nitrated to afford [(NO(2)dppQ)Ru(Cl)(2)] (2).
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Fry
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Rose
authors.forename: Crystal
authors.initials: C
authors.lastname: Nyitray
authors.forename: Pradip K
authors.initials: PK
authors.lastname: Mascharak
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods; D007093:Imidazoles / Q000737:chemistry*; D007202:Indicators and Reagents; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D009569:Nitric Oxide; D010720:Phosphines / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D011804:Quinolines / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D007202:Indicators and Reagents; D008024:Ligands; D010720:Phosphines; D011725:Pyridines; D011804:Quinolines; D009569:Nitric Oxide; D012428:Ruthenium; C037219:quinoline; C044646:phosphine; C023666:pyridine