Phenanthroline complexes bearing fused dipyrrolylquinoxaline anion recognition sites: efficient fluoride anion receptors.
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-1 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.
Mizuno
Toshihisa
T
Department of Chemistry and Biochemistry, The University of Texas, Austin, Texas 78712-1167, USA.
Wei
Wen-Hao
WH
Eller
Leah Renee
LR
Sessler
Jonathan L
JL
D000838:Anions / Q000737:chemistry; D001665:Binding Sites; D005459:Fluorides / Q000737:chemistry*; D007700:Kinetics; D010618:Phenanthrolines / Q000737:chemistry*; D011810:Quinoxalines / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D000838:Anions; D010618:Phenanthrolines; D011810:Quinoxalines; D011956:Receptors, Cell Surface; D005459:Fluorides