The Preparation of 1,2-Bis(2,2′:6′,2′′-Terpyridin-4′yl)Ethanone: The First Example of 4′-Terpyridyls Unsymmetrically Linked by a Functionalized Two-Carbon Chain

Abstract

1,2-Bis(2,2′:6′,2′′-terpyridin-4′yl)ethanone 7, an unsymmetrically linked bis-tridentatate ligand, was prepared by treatment of 4′-cyanomethylterpyridine 10 (RT, overnight) or 4′-(methoxycarbonylmethyl)terpyridine 11 (60°C, 7 h) with concentrated hydrochloric acid. These conversions, which involved an unprecedented homo-coupling reaction, are discussed with the structure of 7 being confirmed by X-ray single crystal analysis. The nitrile starting material 10 was prepared by reaction of the mesylate 9, derived from the known 4′-hydroxymethylterpyridine 8 with sodium cyanide, while ester 11 was prepared by reaction of 10 with methanol in the presence of concentrated sulfuric acid.