Saha Shriya, Doughty Thomas, Banerjee Dibyendu, Patel Sunil K, Mallick Dibyendu, Iyer E Siva Subramaniam, Roy Souvik, Mitra Raja
School of Chemical and Materials Sciences, Indian Institute of Technology Goa, Farmagudi, Goa 403401, India.
School of Chemistry, University of Lincoln, Green Lane, Lincoln, Lincolnshire, LN6 7DL, UK.
Dalton Trans. 2023 Oct 31;52(42):15394-15411. doi: 10.1039/d3dt00441d.
A series of organometallic Re(I)(L)(CO)Br complexes with 4'-substituted terpyridine ligands (L) has been synthesised as electrocatalysts for CO reduction. The complexes' spectroscopic characterisation and computationally optimised geometry demonstrate a facial geometry around Re(I) with three COs and the terpyridine ligand coordinating in a bidentate mode. The effect of substitution on the 4'-position of terpyridine (Re1-5) on CO electroreduction was investigated and compared with a known Lehn-type catalyst, Re(I)(bpy)(CO)Br (Re7). All complexes catalyse CO evolution in homogeneous organic media at moderate overpotentials (0.75-0.95 V) with faradaic yields of 62-98%. The electrochemical catalytic activity was further evaluated in the presence of three Brønsted acids to demonstrate the influence of the p of the proton sources. The TDDFT and ultrafast transient absorption spectroscopy (TAS) studies showed combined charge transfer bands of ILCT and MLCT. Amongst the series, the Re-complex containing a ferrocenyl-substituted terpyridine ligand (Re5) shows an additional intra-ligand charge transfer band and was probed using UV-Vis spectroelectrochemistry.
已合成了一系列带有4'-取代三联吡啶配体（L）的有机金属铼（I）（L）（CO）Br配合物，作为CO还原的电催化剂。配合物的光谱表征和计算优化几何结构表明，铼（I）周围呈面式几何结构，有三个CO，三联吡啶配体以双齿模式配位。研究了三联吡啶4'-位取代基（Re1-5）对CO电还原的影响，并与已知的Lehn型催化剂Re（I）（bpy）（CO）Br（Re7）进行了比较。所有配合物在均相有机介质中以中等过电位（0.75-0.95V）催化CO析出，法拉第产率为62-98%。在三种布朗斯特酸存在下进一步评估了电化学催化活性，以证明质子源的pKa的影响。TDDFT和超快瞬态吸收光谱（TAS）研究显示了ILCT和MLCT的组合电荷转移带。在该系列中，含有二茂铁基取代三联吡啶配体的铼配合物（Re5）显示出额外的配体内电荷转移带，并使用紫外-可见光谱电化学进行了探测。
