Theory and experiment: Anion binding property of novel phenanthroline or aromatic bridged compounds

A series of artificial compounds, phenanthroline or aromatic bridged indoline derivatives, have been designed and synthesized. The interaction of these compounds with biologically important anions fluoride (F−), acetate (AcO−), dihydrogen phosphate (H2PO4−), chloride (Cl−), bromide (Br−) and iodide (I−) was determined by UV–vis, fluorescene titration and theoretical experiments. Results indicate that compound 1 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-1,3-did-ehydebenzo) and 2 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-1,3-didehyde-5-nitrobenzo) containing aromatic bridge do not show binding ability for various anions, and that compound 3 (Di((1″,2″-dihydro-indol-3″-one-2″-hydrazone-1′-hydrazyl)-2′-methylene)-2,9-dial-dehyde-1,10-phenanthroline) containing phenanthroline bridge shows the strongest binding ability for F− among various anions, the moderate binding ability for AcO− and H2PO4−, and almost no binding ability for Cl−, Br−, I−. The different binding ability of aromatic and phenanthroline bridged compounds may be related to the conjugative effect. Whatʹs more, the binding ability of compound 3 with F− is not interfered by the existence of other anions. Hence, theoretical investigations explore the reasons of different binding ability between compound 3 and anions.