Extension of conjugation: probing anion binding strength and reporter mechanisms in (phenyl)cyclopentadienyl and indenyl receptors

摘要: Two families of novel organo-iron functionalized boranes have been developed for anion binding/detection. Synthetically simple phenylferrocene systems, while stable to air and moisture, possess similar binding affinities FcBMes2 no workable discrimination between F− CN−. In addition, reduced electronic communication receptor reporter sites brought about by a lack conformational rigidity means that photochemical electrochemical responses are intrinsically weak. Receptors based on more rigid indenyl framework available in two steps from organic precursors (in ca. 50% yield), feature higher constants especially CN−, consistent with the lower LUMO energies implied extended conjugation. One such system, (4-dimesitylboryl-indenyl)cyclopentadienyl-iron(II), can be shown bind cyanide protic media an accompanying green red/pink colour change. Extremely high selectivity over fluoride hydroxide detection limit 10 ppm represent highly desirable combination among borane derived receptors.