Four octahedral ruthenium(II) azoimine–quinoline complexes having the general molecular formula
[RuII(LAY)(bpy)Cl](PF6) {LAY = YC6H4N@NC(COCH3)@NC9H6N, Y = H (1), CH3 (2), Br (3), NO2 (4) and
bpy = 2,20-bipyrdine} were synthesized. The azoimine–quinoline based ligands behave as NN0N00 tridentate
donors and coordinated to ruthenium via azo-N0 , imine-N0 and quinolone-N00 nitrogen atoms. The
composition of the complexes has been established by elemental analysis, spectral methods (FT-IR, electronic,
1H NMR, UV/Vis and electrochemical (cyclic voltammetry) techniques. The crystal structure of complex 1 is reported. The Ru(II) oxidation state is greatly stabilized by the novel tridentate ligands,
showing Ru(III/II) couples ranging from 0.93–1.27 V vs. Cp2Fe/Cp2Fe+. The absorption spectrum of 1 in
dichloromethane was modeled by time-dependent density functional theory (TD-DFT).