Re(bipy-tBu)(CO)3Cl-improved Catalytic Activity for Reduction of Carbon Dioxide: IR-Spectroelectrochemical and Mechanistic Studies
Re(bipy-tBu)(CO)3Cl-improved Catalytic Activity for Reduction of Carbon Dioxide: IR-Spectroelectrochemical and Mechanistic Studies
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DOI：
10.1021/ic1008363
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发表时间：
2010-10-18
影响因子：
4.6
通讯作者：
Kubiak, Clifford P.
中科院分区：
文献类型：
--
作者：
Smieja, Jonathan M.;Kubiak, Clifford P.
合成并研究了5种Re（bipy）（CO）（3）Cl配合物，其中bipy分别为4，4 '-二羧基-2，2'-联吡啶（1），2，2 '-联吡啶（2），4，4'-二甲基-2，2 '-联吡啶（3），4，4'-二叔丁基-2，2 '-联吡啶（4）和4，4'-二甲氧基-2，2 '-联吡啶（5）。在这组化合物中，发现了一种明显改进的催化剂Re（bipy-tBu）（CO）（3）Cl（4），它在氩气下有两个单电子还原，一个在-1445 mV（vsSCE）可逆，一个在-1830 mV不可逆。在CO2的第二个不可逆波显示了一个大的催化增强电流。使用Levich-Koutecky方法测定扩散系数（中性络合物为1.1 × 10（-5）cm（2）/s，单一还原物质为8.1 × 10（-6）cm（2）/s），并测量了CO2电化学还原的二级速率常数为1000 M-1 s（-1）。进行本体电解研究以测量初级气体产物的法拉第效率，在乙腈中η（CO）= 99 +/-2%。
Five Re(bipy)(CO)(3)Cl complexes were prepared and studied where bipy was 4,4'-dicarboxyl-2,2'-bipyridine (1), 2,2'-bipyridine (2), 4,4'-dimethyl-2,2'-bipyridine (3), 4,4'-di-tert-butyl-2,2'-bipyridine (4), and 4,4'-dimethoxy-2,2'-bipyridine (5). From this group, a significantly improved catalyst, Re(bipy-tBu)(CO)(3)Cl (4), for the reduction of carbon dioxide to carbon monoxide was found. The complex shows two one-electron reductions under argon, one reversible at -1445 mV (vs SCE), and one irreversible at -1830 mV. Under CO2 the second irreversible wave displays a large catalytic enhancement in current. Diffusion coefficients were determined using the Levich-Koutecky method (1.1 X 10(-5) cm(2)/s for the neutral complex and 8.1 x 10(-6) cm(2)/s for the singly reduced species), and a second order rate constant for the electrochemical reduction with CO2 of 1000 M-1 s(-1) was measured. Bulk electrolysis studies were performed to measure Faradaic efficiencies for the primary gaseous products, eta(CO) = 99 +/- 2% in acetonitrile.