Boston David J, Pachón Yeimi M Franco, Lezna Reynaldo O, de Tacconi N R, MacDonnell Frederick M
Department of Chemistry and Biochemistry, The University of Texas at Arlington , Arlington, Texas 76019-0065, United States.
Inorg Chem. 2014 Jul 7;53(13):6544-53. doi: 10.1021/ic500051m. Epub 2014 Jun 9.
The ruthenium complexes Ru(phen)2(ptpbα) (Ruα) and Ru(phen)2(ptpbβ) (Ruβ), where phen =1,10-phenanthroline ; ptpbα = pyrido[2',3':5,6]pyrazino[2,3-f][1,10]phenanthroline; ptpbβ = pyrido[3',4':5,6]pyrazino[2,3-f][1,10]phenanthroline, are shown as electrocatalysts and photocatalysts for CO2 reduction to formate, formaldehyde, and methanol. Photochemical activity of both complexes is lost in water but is retained in 1 M H2O in DMF. Controlled current electrolysis of a solution of Ruβ in CO2 saturated DMF:H2O (1 M) yields predominantly methanol over a 6 h period at ∼ -0.60 V versus Ag/AgCl, with traces of formaldehyde. After this time, the potential jumped to -1.15 V producing both methanol and CO as products. Irradiation of Ruβ in a solution of DMF:H2O (1 M) containing 0.2 M TEA (as the sacrificial reductant) yields methanol, formaldehyde, and formate. Identifications of all of the relevant redox and protonated states of the respective complexes were obtained by a combination of voltammetry and differential reflectance measurements. Spectroelectrochemistry was particularly useful to probe the photochemical and electrochemical reduction mechanisms of both complexes as well as the complexes speciation in the absence and presence of CO2.
钌配合物Ru(phen)2(ptpbα)（Ruα）和Ru(phen)2(ptpbβ)（Ruβ），其中phen = 1,10 - 菲咯啉；ptpbα = 吡啶并[2',3':5,6]吡嗪并[2,3 - f][1,10]菲咯啉；ptpbβ = 吡啶并[3',4':5,6]吡嗪并[2,3 - f][1,10]菲咯啉，被展示为将二氧化碳还原为甲酸盐、甲醛和甲醇的电催化剂和光催化剂。两种配合物的光化学活性在水中丧失，但在DMF中的1 M H2O中得以保留。在相对于Ag/AgCl约 - 0.60 V的电位下，对Ruβ在二氧化碳饱和的DMF:H2O（1 M）溶液中进行恒电流电解6小时，主要生成甲醇，并伴有痕量甲醛。此时间段过后，电位跃升至 - 1.15 V，产物为甲醇和一氧化碳。在含有0.2 M TEA（作为牺牲还原剂）的DMF:H2O（1 M）溶液中对Ruβ进行光照，生成甲醇、甲醛和甲酸盐。通过伏安法和差分反射测量相结合的方法，确定了各配合物所有相关的氧化还原和质子化状态。光谱电化学对于探究两种配合物的光化学和电化学还原机制以及在有无二氧化碳存在情况下配合物的形态特别有用。
