Vectorial property dependence in bis4 '-(n-pyridyl)-2,2 ': 6 ',2 ''-terpyridineiron(II) and ruthenium(II) complexes with n=2, 3 and 4

A comparative structural and spectroscopic investigation of the complexes [M(1)(2)](2+), [M(2)(2)](2+) and [ M( 3) 2] 2+ in which M = Fe or Ru, and ligands 1, 2 and 3 are 4`-(2-pyridyl)-, 4`-(3-pyridyl)- and 4`-(4-pyridyl)-2,2`:6`,2``-terpyridine, respectively, is reported. The complexes [Ru(1)(2)](2+), [Ru(2)(2)](2+) and [Ru(3)(2)](2+) undergo mono- and bis-N-methylation. The consequences of methylation on the absorption spectra and electrochemical properties are discussed; the solid-state structure of the bis(N-methylated) derivative of [Ru(2)(2)][PF6](2) is presented.