Anion Influence of Emission Properties and DFT Calculations of Diprotonated and Triprotonated Terpyridines

Abstract

Intense blue emissions were obtained by the interaction between protonated pyridine rings and the adjacent anion or adjacent PF6−. These compounds possess hydrogen bonds, which restrain the nonradiative decay to produce strong emission. By reacting of (L=terpy, tterpy and Clterpy) with a variety of acid (HF, HCl, HBr, H2SO4 and H3PO4) in water, triprotonated and diprotonated compounds [LH3]3+ and [LH2]2+were prepared. Abbreviations used are terpy=2,2’:6’,2’’‐terpyridine, tterpy=4’‐(4‐tolyl)‐2,2’:6’,2’’‐terpyridine and Clterpy=4’‐Chloro‐2,2’:6’,2’’‐terpyridine. Intense emission in acetonitrile (Φ = 0.30) was obtained by attaching two protons to the nitrogen in [(tterpyH2)H2O]2+ and intermolecular hydrogen bonds to the two adjacent F− atoms in PF6−.