A benzimidazolyl terpyridine-Fe 2+ system and its recognition driven molecular model of a traffic light

Abstract

A new benzimidazolyl terpyridyl ligand (BIT) selectively detects Fe 2+ , F − and CN − ions in acetonitrile. The Fe 2+ complex [Fe(H-BIT) 2 ]·(ClO 4 ) 4 (1) displays the fast and selective detection of 2,4,6-trinitrophenol (TNP) with strong binding (log β = 8.51 ± 0.24) and a low limit of detection (1.4 × 10 −7 M) among several nitroaromatics. The color of complex 1 changes from purple to red, yellow, and green upon the separate addition of 2,4,6-trinitrophenol and tetrabutylammonium salts of fluoride and cyanide, respectively. The overall color changes thus display a model of a traffic light. The structures of BIT, 1 and [Fe(BIT) 2 ]·(TNP) 2 (2) have been well characterized using spectroscopic techniques and single crystal X-ray crystallography. © The Royal Society of Chemistry.