A Family of Ruthenium Aryls Incorporating an η2-Bonded Nitrite or Nitrate and a Pendant Imine−Phenol Function
journal contributionposted on 01.01.1997, 00:00 by Prasanta Ghosh, Animesh Chakravorty
The reaction of carbonylchloro[4-methyl-6-(NR-iminio)phenolato-C2,O]bis(triphenylphosphine)ruthenium(II), RuII(η2-RL)(PPh3)2(CO)Cl (R = Ph, p-MeC6H4), 1, with NaY (Y = NO2, NO3) has afforded new organometallics of the type carbonyl(nitrito or nitrato)[4-methyl-6-(NR-imino)phenol-C2]bis(triphenylphosphine)ruthenium(II), RuII(η1-RL)(PPh3)2(CO)(η2-Y) (2, Y = NO2; 3, Y = NO3). The transformation probably occurs via associative cis attack on chloride by Y-. The reconversion 2 (3) → 1 is achievable by treating 2 (3) with excess halide. The X-ray structures of Ru(η1-PhL)(PPh3)2(CO)(η2-NO2) and Ru(η1-PhL)(PPh3)2(CO)(η2-NO3) have revealed the presence of (i) O,O‘-chelated Y-, (ii) monodentate PhL binding via an aromatic carbon atom lying cis to the CO molecule, and (iii) O(phenolic)···N(imine) hydrogen bonding. The interconversion between 1 and 2 (3) is attended with iminium−phenolate to imine−phenol tautomerization and a change in the rotational conformation of the RL ligand. Crystal data for the complexes are as follows. Ru(η1-PhL)(PPh3)2(CO)(η2-NO2): crystal system, monoclinic; space group, P21/c; a = 18.597(9) Å, b = 11.947(7) Å, c = 20.362(5) Å, β = 101.15(3)°; V = 4439(4) Å3; Z = 4; R = 0.0427; Rw = 0.0458. Ru(η1-PhL)(PPh3)2(CO)(η2-NO3): crystal system, monoclinic; space group, P21/c; a = 18.726(11) Å, b = 11.857(4) Å, c = 20.443(8) Å, β = 102.77(4)°; V = 4426(3) Å3; Z = 4; R = 0.0654; Rw = 0.0659.