Tuning the Photophysical Properties of Ru(II) Monometallic and Ru(II),Rh(III) Bimetallic Supramolecular Complexes by Selective Ligand Deuteration
详细信息 查看全文
- 作者：Alec T. Wagner ; Rongwei Zhou ; Kevan S. Quinn ; Travis A. White ; Jing Wang ; Karen J. Brewer
- 刊名：Journal of Physical Chemistry A
- 出版年：2015
- 出版时间：July 2, 2015
- 年：2015
- 卷：119
- 期：26
- 页码：6781-6790
- 全文大小：501K
- ISSN：1520-5215
文摘
A series of three new complexes of the design [(TL)2Ru(BL)]2+, two new complexes of the design [(TL)2Ru(BL)Ru(TL)2]4+, and three new complexes of the design [(TL)2Ru(BL)RhCl2(TL)]3+ (TL = bpy or d8-bpy; BL = dpp or d10-dpp; TL = terminal ligand; BL = bridging ligand; bpy = 2,2鈥?bipyridine; dpp = 2,3-bis(2-pyridyl)pyrazine) were synthesized and the 1H NMR spectroscopy, electrochemistry, electronic absorbance spectroscopy, and photophysical properties studied. Incorporation of deuterated ligands into the molecular architecture simplifies the 1H NMR spectra, allowing for complete 1H assignment of [(d8-bpy)2Ru(dpp)](PF6)2 and partial assignment of [(bpy)2Ru(d10-dpp)](PF6)2. The electrochemistry for the deuterated and nondeuterated species showed nearly identical redox properties. Electronic absorption spectroscopy of the deuterated and nondeuterated complexes are superimposable with the lowest energy transition being Ru(d蟺) 鈫?BL(蟺*) charge transfer in nature (BL = dpp or d10-dpp). Ligand deuteration impacts the excited-state properties with an observed increase in the quantum yield of emission (桅em) and excited-state lifetime (蟿) of the Ru(d蟺) 鈫?d10-dpp(蟺*) triplet metal-to-ligand charge transfer (3MLCT) excited state when dpp is deuterated, and a decrease in the rate constant for nonradiative decay (knr). Choice of ligand deuteration between bpy and dpp strongly impacts the observed photophysical properties with BL = d10-dpp complexes showing an enhanced 桅em and 蟿, providing further support that the lowest electronic excited state populated via UV or visible excitation is the photoactive Ru(d蟺) 鈫?dpp(蟺*) CT excited state. The Ru(II),Rh(III) complex incorporating the deuterated BL shows increased hydrogen production compared to the variants incorporating the protiated BL, while demonstrating identical dynamic quenching behaviors in the presence of sacrificial electron donor.