Naokazu Yoshikawa
Nara Women’s University, Japan
Title: Synthesis, X-ray crystal structure, emission property, and DFT calculation of monoprotonated polypyridine
Biography
Biography: Naokazu Yoshikawa
Abstract
A series of metal-free compounds, i.e., bpyHPF6 (1), dmbpyHPF6 (2), phenHPF6 (3) dpphenPF6 (4), bqnHPF6 (5) and ppyHPF6 (7) were newly prepared and characterized by electrospray ionization mass spectrometry, and UV-vis spectroscopy. Abbreviations used are bpy =　2,2’-bipyridine, dmbpy =　4, 4’-dimethyl-2, 2’-bipyridine, phen = 1,10-phenanthroline, bqn = 2,2’-biquinoline and ppy = phenylpyrizine. The x-ray crystal structures of the four compounds 1, 2, 3, 4 5 and 7 were determined. Monoprotonated pyridine rings are hydrogen bonded intramolecularly to the adjacent pyridine ring in compounds 1, 2, 3, 4 and 5. The p-p* absorption bands in the UV region for 1, 2, 3, 4 and 5 in acetonitrile were red-shifted relative to those of the corresponding neutral unprotonated compounds. Density functional theory was applied to interpret the planarity in 1. The attachment of one proton to the one nitrogen in 5 leads to the remarkable emission (F = 0.10). The attachment of one proton to one nitrogen in 4 also gives the large quantum yield.