Ultrafast relaxation dynamics of amine-substituted bipyridyl ruthenium(ii) complexes

• DOI: 10.1016/j.cplett.2017.03.017
• Publication Date: 2017-03-10T09:31:40Z
• Authors: Hongwei Song; Xian Wang; WenWen Yang; Guiying He; Zhuoran Kuang; Yang Li; Andong Xia; Yu-Wu Zhong; Fan'ao Kong
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract The excited state properties of a series of ruthenium(II) amine-substituted bipyridyl complexes, [Ru(bpy)n(NNbpy)3−n]2+, were investigated by steady-state and transient absorption spectroscopy, as well as quantum chemical calculations. The steady-state absorption spectra of these complexes in CH3CN show a distinct red-shift of the 1MLCT absorption with increasing numbers of amine substituent, whereas the emission spectra indicate an energy gap order of [Ru(bpy)3]2+ > [Ru(bpy)2(NNbpy)]2+ > [Ru(NNbpy)3]2+ > [Ru(bpy)(NNbpy)2]2+. Nanosecond, femtosecond transient absorption and electrochemical measurements suggest that NNbpy ligand has a strong influence on the electronic and emission properties of these complexes, due to electron-rich amine substituent. We illustrate how the numbers of amine substituent modulate the spectroscopic properties of transition metal complexes, which is related to the design of new electro-active systems with novel photoelectrochemical properties.