Tamaki Yusuke, Koike Kazuhide, Morimoto Tatsuki, Yamazaki Yasuomi, Ishitani Osamu
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology , O-okayama 2-12-1-NE-1, Meguro-ku, Tokyo 152-8550, Japan.
Inorg Chem. 2013 Oct 21;52(20):11902-9. doi: 10.1021/ic4015543. Epub 2013 Oct 1.
The novel supramolecular complexes, which are composed of an Os(5dmb)2(BL)-type complex (5dmb = 5,5'-dimethyl-2,2'-bipyridine; BL = 1,2-bis(4'-methyl-[2,2'-bipyridin]-4-yl)ethane) as a photosensitizer and cis,trans-Re(BL)(CO)2{P(p-X-C6H4)3}2-type complexes (X = F, Cl) as a catalyst, have been synthesized. They photocatalyzed selective reduction of CO2 to CO under red-light irradiation (λ > 620 nm). The photocatalytic abilities were affected by the phosphine ligands on the Re unit, and the supramolecule with P(p-Cl-C6H4)3 ligands exhibited better photocatalysis (ΦCO = 0.12, TONCO = 1138, TOFCO = 3.3 min(-1)). The detailed studies clarified the electron balance and material balance; i.e., one molecule of the sacrificial electron donor (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH)) donated two electrons, one molecule of CO2 accepted the two electrons, and another CO2 molecule served as an "O(2-)" acceptor to give each molecule of the two-electron oxidized compound of BIH, CO, and HCO3(-).
新型超分子配合物已被合成，其由作为光敏剂的Os(5dmb)2(BL)型配合物（5dmb = 5,5'-二甲基-2,2'-联吡啶；BL = 1,2-双(4'-甲基-[2,2'-联吡啶]-4-基)乙烷）和顺式、反式-Re(BL)(CO)2{P(p-X-C6H4)3}2型配合物（X = F、Cl）作为催化剂组成。它们在红光照射（λ > 620 nm）下光催化二氧化碳选择性还原为一氧化碳。光催化能力受铼单元上的膦配体影响，具有P(p-Cl-C6H4)3配体的超分子表现出更好的光催化性能（ΦCO = 0.12，TONCO = 1138，TOFCO = 3.3 min(-1)）。详细研究阐明了电子平衡和物料平衡；即，一分子牺牲电子供体（1,3-二甲基-2-苯基-2,3-二氢-1H-苯并[d]咪唑（BIH））提供两个电子，一分子二氧化碳接受这两个电子，另一分子二氧化碳作为“O(2-)”受体，生成BIH的双电子氧化产物、一氧化碳和碳酸氢根（HCO3(-)）的每个分子。
