Cationic bipy induced the three dimensional supramolecules based on azoxybenzene tetracarboxylate: Structures and NIR luminescence property

Abstract

Series of Ln(III) coordination polymers, namely, {[Ln(Oaobtc)(H2O)4]·Hbipy·H2O}n(H4Oaobtc = oxidation azoxybenzene - 2, 2′, 3, 3′-tetracarboxylic acid, bipy = 4,4′-bipyridine, and Ln = Pr(1), Nd(2), Ho(3), Er(4), Yb(5), respectively) have been designed, afforded and luminescence characterized systematically. The family coordination polymers are nearly isostructural sets, featuring one dimensional (1D) zigzag double chain edifice structure, with cationic Hbipy+ guest being located along two sides. These 1D chains are interlinked into 2D network, and are further extended into 3D supramolecular architecture through hydrogen bonding interactions from the cationic Hbipy+ moiety. The photo luminescence emission spectra of polymer 1 and 4 are based on the H4aobtc acid ligand, while 2, 3 and 5 display the emissions originated from characteristic f-f transitions of Ln(III) ions within near-infrared (NIR) regions.