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The synthesis, structure and photophysical properties of the complexes [Ru[(CO)(TFA) (PPh 3 ) 2 (L)][(L = ppy = 2-phenylpyridine, ( 1a ); L = 2–(p–tolyl)pyridine] ( 1b ), are reported. The complexes were characterized by UV-VIS, IR and NMR and by single-crystal X-ray diffraction techniques. We also report the synthesis, structure and photophysical properties of [Ru(CO)(L)(PPhMe 2 ) 2 (L′)] + [PF 6 ] − [L′ = bipyridine, L = TFA, ( 3a ); L = H, ( 3b ) and L = H, L′ = 4,4′-dimethlyl bipyridine ( 3c )]. These compounds were characterized by UV-VIS, IR and NMR techniques and by a single crystal X-ray diffraction in the case of 3a. The solid state structure of [Ru(Me 2 PhP) 2 (CO) 2 (TFA) 2 (2) which is the starting material for the synthesis 3a - 3c is also reported to verify the trans relationship of the less bulky PPhMe 2 and for comparison with the previously reported PPh 3 analogs. The purpose of this study was to determine the impact, if any, of replacing bpy with ppy in the case of 1a and alkylation of the benzene ring in the case of 1b on the photophysical and electrochemical properties compared to related Ru(bpy) complexes. In contrast to the bpy analogs 1a and 1b showed reversible 1e − oxidations and blue-shifted MLCT absorptions. In the case of 3a - 3c we were interested in the effect on the photophysical properties of substituting PPh 3 with the less bulky but more electron donating PPhMe 2 . There were only minor changes in the photophysical and electrochemical properties relative to the previously reported PPh 3 analogs. [ABSTRACT FROM AUTHOR]

The electrochemical behavior of the ruthenium(II) diimine complexes [Ru(CO)(CF 3 CO 2 )(dppene)(5-R-phen)][PF 6 ] (dppene = 1,2-diphenylphosphinoethene; phen = 1,10-phenanthroline; R = H, 1 ; R = NH 2 , 2 ; R = cholestoryl carbamate, 3 ; R = 1,2-dihexadecanoyl- sn -glycero-3-phosphoethanolamine, 4 ), [Ru(CO)(H)(4,4′-R-bpy)(R′Ph 2 P) 2 ][PF 6 ] (bpy = 2,2′-bipyridine; R = H, R′ = Ph, 5 ; R = H, R′ = 1,2-dihexadecanoyl- sn -glycero-3-phosphoethanolamine, 6 ; R = 1,2-dihexadecanoyl- sn -glycero-3-phosphoethanolamine, R′ = Ph, 7 ), [Ru(bpy) 2 (5-R-phen)][PF 6 ] 2 (R = NH 2 , 8 ; R = cholestoryl carbamate, 9 ; R = 1,2-dihexadecanoyl- sn -glycero-3-phosphoethanolamine, 10 ) is reported. Complexes 1 – 6 give cyclovoltammetric (CV) responses with multiple ill-defined reduction waves and one oxidation wave, all of which were chemically irreversible. Complexes 5 and 7 , containing axially coordinating phosphines, showed reversible oxidation and reduction CV responses, while 6 showed redox waves similar to 3 . Complexes 8 – 10 show a metal-centered irreversible oxidation around +1.4 V that, in the case of 8 and 9 , is heavily modified by adsorption phenomena. In the negative part of the CV, 9 and 10 show a single chemically and electrochemically reversible 1e − reduction both at E °′ = −1.29 V, about 500 mV cathodically shifted with respect to 8 . The interactions of complexes 1 and 2 with bovine serum albumin (BSA) and double stranded DNA (ds-DNA) were also studied by electrochemical methods. Both complexes showed strong binding to BSA. Evidence for intercalation of both complexes with DNA is presented, with 1 showing a stronger interaction than 2 . [ABSTRACT FROM AUTHOR]