Phenanthroline Complexes Bearing Fused Dipyrrolylquinoxaline Anion Recognition Sites:  Efficient Fluoride Anion Receptors. Toshihisa Mizuno Wen-Hao Wei Leah Renee Eller Jonathan L. Sessler 10.1021/ja017298t.s001 https://acs.figshare.com/articles/journal_contribution/Phenanthroline_Complexes_Bearing_Fused_Dipyrrolylquinoxaline_Anion_Recognition_Sites_Efficient_Fluoride_Anion_Receptors_/3639663 Novel anion recognition host molecules, tris-1,10-phenanthroline cobalt(III) and bis-2,2‘-bipyridine mono-1,10-phenanthroline ruthenium(II) complexes bearing fused dipyrrolylquinoxaline moieties have been synthesized. As determined by UV−vis spectroscopic and electrochemical studies, these metal complexes bind fluoride with high affinity in polar media both in absolute terms and relative to the metal-free phenanthroline dipyrrolylquinozaline precursor from which they are derived (fluoride is bound to the tris-1,10-phenanthroline cobalt(III) dipyrrolylquinoxaline system with a 1:1 binding constant of 54 000 M<sup>-1</sup> in DMSO). The large observed binding constants are ascribed to two factors, (i) the presence of a phenanthroline-coordinated cationic charge that decreases the electron density on the pyrrole NH protons and (ii) pure electrostatic effects. 2002-01-25 00:00:00 phenanthroline Fused presence Efficient cationic 54 000 M cobalt ii tris dipyrrolylquinozaline media charge affinity Dipyrrolylquinoxaline factor metal complexes bind fluoride pyrrole NH protons Anion Bearing ruthenium spectroscopic Complexe electron density Fluoride dipyrrolylquinoxaline moieties Phenanthroline term precursor UV Site 54 000 electrochemical studies Receptor binding constants DMSO Novel anion recognition host molecules Recognition