Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.
Chemistry. 2020 Dec 9;26(69):16365-16373. doi: 10.1002/chem.202002558. Epub 2020 Nov 11.
We have prepared Zn and free-base porphyrins appended with a fac-Re(phen)(CO) Br (where phen is 1,10-phenanthroline) at the meso position of the porphyrin, and performed photocatalytic CO reduction using porphyrin-Re dyads in the presence of either triethylamine (TEA) or 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. The Zn porphyrin dyad showed a high turnover number for CO production compared with the free-base porphyrin dyad, suggesting that the central Zn ion of porphyrin plays an important role in suppressing electron accumulation on the porphyrin part and achieving high durability of the photocatalytic CO reduction using both TEA and BIH. The effect of acids on the CO reduction was investigated using the Zn porphyrin-Re dyad and BIH. Acetic acid, a relatively strong Brønsted acid, rapidly causes the porphyrin's color to fade upon irradiation and dramatically decreases CO production, whereas proper weak Brønsted acids such as 2,2,2-trifluoroethanol and phenol enhance the CO reduction.
我们制备了锌卟啉和自由碱基卟啉，在卟啉的中位处连接了 fac-Re(phen)(CO)Br（其中 phen 是 1,10-菲咯啉），并在三乙胺 (TEA) 或 1,3-二甲基-2-苯基-2,3-二氢-1H-苯并[d]咪唑 (BIH) 作为电子供体的存在下进行了卟啉- Re 二聚体的光催化 CO 还原。与自由碱基卟啉二聚体相比，Zn 卟啉二聚体显示出更高的 CO 生成周转数，这表明卟啉的中心 Zn 离子在抑制电子在卟啉部分的积累和实现使用 TEA 和 BIH 的光催化 CO 还原的高耐久性方面发挥重要作用。使用 Zn 卟啉-Re 二聚体和 BIH 研究了酸对 CO 还原的影响。乙酸是一种相对较强的 Brønsted 酸，在照射下会迅速使卟啉的颜色褪色，并大大降低 CO 的生成量，而适当的弱 Brønsted 酸，如 2,2,2-三氟乙醇和苯酚，则会增强 CO 的还原。
