Koide Taro, Aritome Isao, Saeki Tatsuya, Morita Yoshitsugu, Shiota Yoshihito, Yoshizawa Kazunari, Shimakoshi Hisashi, Hisaeda Yoshio
Department of Chemistry and Biochemistry, Graduate School of Engineering and Institute for Materials Chemistry and Engineering, Kyushu University, Moto-oka 744, Nishi-ku, Fukuoka-shi, Fukuoka 819-0395, Japan.
Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, Kasuga 1-13-27, Bunkyo-ku, Tokyo 112-8551, Japan.
ACS Omega. 2018 Apr 10;3(4):4027-4034. doi: 10.1021/acsomega.8b00239. eCollection 2018 Apr 30.
The interesting redox properties and reactivity of metalloporphycene have been studied for decades; however, the detailed experimental investigation on the reactivity and reaction mechanism under inert condition combined with theoretical calculations had not been performed so far. In this study, the novel reactivity of the reduced form of the cobalt porphycene with alkyl halides to form cobalt-carbon (Co-C) bonds was revealed. Under electrochemical reductive conditions, not the central cobalt, but the ligand was reduced and reacted with alkyl halides to afford the cobalt-alkyl complexes under N atmosphere in a glovebox. The reaction mechanism was clarified by the combination of experimental and theoretical studies that the porphycene ligand works as a noninnocent ligand and allows the S2-type Co-C bond formation. This result provides us the possibility of the reaction triggered by the reduction of ligand with macrocyclic π-conjugated system, not by the reduction of metal.
几十年来，人们一直在研究金属卟啉有趣的氧化还原性质和反应活性；然而，到目前为止，尚未在惰性条件下结合理论计算对其反应活性和反应机理进行详细的实验研究。在本研究中，揭示了钴卟啉还原形式与卤代烃形成钴 - 碳（Co - C）键的新型反应活性。在电化学还原条件下，在手套箱中的氮气气氛下，不是中心钴被还原，而是配体被还原并与卤代烃反应生成钴 - 烷基配合物。通过实验和理论研究相结合，阐明了反应机理，即卟啉配体作为非无辜配体，允许形成S2型Co - C键。这一结果为我们提供了由具有大环π共轭体系的配体还原引发反应的可能性，而非由金属还原引发反应。
