Pentamethylcyclopentadienyl ruthenium(II) complexes of para-substituted N-(pyrid-2-ylmethylene)-phenylamine ligands: syntheses, spectral and structural studies

Abstract

The reaction of [(η 5-C 5Me 5)Ru(PPh 3) 2Cl] ( 1) with acetonitrile in the presence of excess NH 4PF 6 leads to the formation of the cationic ruthenium(II) complex [(η 5-C 5Me 5)Ru(PPh 3) 2(CH 3CN)]PF 6 ( 2). The complex ( 2) reacts with a series of N, N′ donor Schiff base ligands viz. para-substituted N-(pyrid-2-ylmethylene)-phenylamines (ppa) in methanol to yield pentamethylcylopentadienyl ruthenium(II) Schiff base complexes of the formulation [(η 5-C 5Me 5)Ru(PPh 3)(C 5H 4N-2-CH N-C 6H 4- p-X)]PF 6 [ 3a] PF 6 –[ 3f] PF 6 , where C 5Me 5 = pentamethylcylopentadienyl, X = H, [ 3a] PF 6, Me, [ 3b] PF 6, OMe, [ 3c] PF 6, NO 2, [ 3d] PF 6, Cl, [ 3e] PF 6, COOH, [ 3f] PF 6. The complexes were isolated as their hexafluorophosphate salts. The complexes were fully characterized on the basis of elemental analyses and NMR spectroscopy. The molecular structure of a representative complex, [(η 5-C 5Me 5)Ru(PPh 3)(C 5H 4N-2-CH N-C 6H 4- p-Cl)]PF 6 [ 3e] PF 6, has been established by X-ray crystallography.