Phenyl‐Bridged Ferrocene/Ruthenium Alkynyl Heterobimetallic Complexes: Syntheses, Characterization, and Electrochemical, Spectroscopic, and Computational Investigation

Abstract

Two isomeric phenyl‐bridged ferrocenyl and ruthenium alkynyl complexes 1 and 2 are synthesized and characterized through NMR, elemental analysis, and X‐ray single‐crystal diffraction. The electronic properties of the complexes are investigated via electrochemical studies, UV/Vis‐NIR and IR spectroelectrochemistry, and theoretical calculations. Cyclic voltammetry and square‐wave voltammetry technologies show two successive redox behaviors from Ru(II) and ferrocenyl centers in 1 and 2, respectively. These behaviors are supported by the dominant spin–spin density distribution in RuCp*(dppe) terminals. The large potential difference (ΔE1/2) and comproportionation constants (Kc) observed in complex 1 suggest that 1+ has better chemical stability than 2+. Strong electronic communication from 1+ are detected through the observed NIR absorption band in 1+ and large Δν(C≡C) value of 1→1+. The broad NIR absorption in 1+ is reproduced and assigned to ferrocenyl to the Ru(III) center charge transfer transition with major contributions from the β‐HOSO→β‐LUSO transition.

Preparation of new organo-ruthenium(ii) complexes and their nucleic acid/albumin binding efficiency and in vitro cytotoxicity studies

“…The quasi-reversible ligand oxidation and ligand reduction have been assigned to the oxidation of Fe( ii )/Ru( ii )–Fe( iii )/Ru( ii ) and the reduction of Fe( ii )/Ru( ii )–Fe( i )/Ru( ii ), respectively. 50,51…”

“…The quasi-reversible ligand oxidation and ligand reduction have been assigned to the oxidation of Fe(II)/Ru(II)-Fe(III)/Ru(II) and the reduction of Fe(II)/Ru(II)-Fe(I)/Ru(II), respectively. 50,51 DNA binding studies UV-Vis absorption spectral studies. The DNA binding interactions of the ligands (AFIZ and BFIZ) and complexes (PRAFIZ and PRBFIZ) were determined by UV-visible absorption spectral measurements, by adding CT-DNA to compounds (R = [DNA]/[complex] = 25) in 5% DMF/5 mM Tris-HCl/50 mM NaCl buffer solution.…”

Modulation of Electrochemical and Spectroscopic Properties in Ru(II)‐Terpyridyl End‐Capped Homobimetallic Organometallic Complexes by Varying π‐Conjugated Organic Spacers

“…This class of rigid wire‐like linear π‐conjugated systems combined with two redox‐active metal termini, [ML x n ‐μ‐(BL)‐ML x n+1 ] (BL=bridging ligand, M=redox active metal termini), generates mixed‐valence state when one of the metal center undergoes a chemically or electrochemically reversible redox process generating different oxidation states in the two metal termini. Since the pioneering discovery of the binuclear Ru 2 (II,III) complex, [(NH 3 ) 5 Ru‐pyrazine‐Ru(NH 3 ) 5 ] 5+ by Creutz and Taube, [30–31] a significant number of mixed‐valence metal complexes have been intensively investigated by varying the redox‐active metallic termini and also modifying the π‐conjugated bridges in order to tune the intermolecular electronic communication along the molecular backbone [32–60] …”