Structure, spectroscopy and DFT studies of a novel one-dimensional Cu-diphosphonate coordination polymer.

By introducing the second ligand 2,2'-bipy, a new copper(II) diphosphonate [Cu(HL)(2,2′-bipy)] 1 (HL = 1-hydroxyethylidenediphosphonate, 2,2′-bipy = 2,2′-bipyrimidine) has been hydrothermally synthesized and characterized by powder X-ray diffraction, elemental analysis, IR and TG-DTA. The single-crystal X-ray diffractions show that compound 1 possess a three-dimensional supramolecular structure, built from 1D chain via a single-bridge O-P-O in syn-anti fashion based on mononuclear unit [CuON]. UV-vis spectra and the nature of electron transfer of 1 are investigated, and the experimental results are in agreement with the quantum chemistry calculation using the B3LYP/6-31G* method. Fluorescent measurements reveal that two emission peaks of 1 centered at 382.5 and 424.5 nm are mainly caused by intraligand π*- π emission state of the second ligands (375, 429.5 nm, λ = 235 nm). Results of electrochemical studies (CV) indicate a higher donor ability of 1. [ABSTRACT FROM AUTHOR]