화학공학소재연구정보센터
Inorganic Chemistry, Vol.44, No.24, 8733-8739, 2005
[1,10]-Phenanthrolin-2-yl ketones and their coordination chemistry
A synthetic protocol involving the Friedlander reaction of 8-amino-7-quinolinecarbaldehyde followed by potassium dichromate oxidation was applied to 2,3,4-pentanetrione-3-oxime and 1-(pyrid-2'-yl)propane-1,2-dione-1-oxime to provide the ligands di-(phenathrolin-2-yl)-methanone (1) and phenanthrolin-2-yl-pyrid-2-yl-methanone (8), respectively. Ligand 1 complexed as a planar tetradentate with Pd(II) to form [Pd(1)](BF4)2 and with Ru(II) and two 4-substituted pyridines (4-R-py) to form [Ru(1)(4-R-py)(2)](PF6)(2) where R = CF3, CH3, and Me2N. With (Ru(bpy)(2)Cl-2], the dinuclear complex [(bpy)(2)Ru(l)Ru(bpy)21(PF6)4 was formed (bpy = 2,2'-bipyridine). Ligand 8 afforded the homoleptic Ru(II) complex [Ru(8)(2)](PF6)(2), as well as the heteroleptic complex [Ru(8)(tpy)](PF6)(2) (tpy = 2,2';6,2"-terpyridine). The ligands and complexes were characterized by their NMR and IR spectra, as well as an X-ray structure determination of [Ru(1)(4-CH3-py)(2)](PF6)(2). Electrochemical analysis indicated metal-based oxidation and ligand-based reduction that was consistent with results from electronic absorption spectra. The complexes [Ru(1)(4-R-py)(2)](PF6)(2) were sensitive to the 4-substituent on the axial pyridine: electron donor groups facilitated the oxidation while electron-withdrawing groups impeded it.