Synthesis, Characterization, Photophysical, and Anion-Binding Studies of Luminescent Heteroleptic Bis-Tridentate Ruthenium(II) Complexes Based on 2,6-Bis(Benzimidazole-2-yl)Pyridine and 4′-Substituted 2,2′:6′,2′′ Terpyridine Derivatives

TLDR: The absorption spectra, redox behavior, and luminescence properties of the ruthenium(II) complexes have been thoroughly investigated, and it has been observed that the metalloreceptors act as sensors for F(-, AcO(-), and to some extent H(2)PO(4)(-).

Abstract: A series of heteroleptic tridentate ruthenium(II) complexes of composition [(H2pbbzim)Ru(tpy-X)](PF6)2 (1−7), where H2pbbzim = 2,6-bis(benzimidazole-2-yl)pyridine and tpy-X = 4′-substituted terpyridine ligands with X = H, p-methyl phenyl (PhCH3), p-bromomethylphenyl (PhCH2Br), p-dibromomethylphenyl (PhCHBr2), p-cyanomethylphenyl (PhCH2CN), p-triphenylphosphonium methylphenyl bromide (PhCH2PPh3Br), and 4′-phenylformyl (PhCHO) groups, has been synthesized and characterized by using standard analytical and spectroscopic techniques. These compounds were designed to increase the excited-state lifetime of ruthenium(II) bisterpyridine-type complexes. The X-ray crystal structure of a representative compound 2, which crystallized with monoclinic space group P2(1)/c, has been determined. The absorption spectra, redox behavior, and luminescence properties of the ruthenium(II) complexes have been thoroughly investigated. All of the complexes display moderately strong luminescence at room temperature with lifetimes in...