Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany.
Inorg Chem. 2023 Apr 24;62(16):6375-6386. doi: 10.1021/acs.inorgchem.3c00253. Epub 2023 Apr 12.
Two homoleptic Fe(II) complexes in different spin states bearing superbasic terpyridine derivatives as ligands are investigated to determine the relationship between spin state and electrochemical/spectroscopic behavior. Antiferromagnetic coupling between a ligand-centered radical and the high-spin metal center leads to an anodic shift of the first reduction potential and results in a species that shows mixed valency with a moderately intense intervalence-charge-transfer band. The differences afforded by the different spin states extend to the electrochemical reactivity of the complexes: while the low-spin species is a precatalyst for electrocatalytic CO reduction and leads to the preferential formation of CO with a Faradaic efficiency of 37%, the high-spin species only catalyzes proton reduction at a modest Faradaic efficiency of approximately 20%.
研究了两种具有超碱性三吡啶衍生物配体的同型 Fe(II) 配合物，以确定自旋态与电化学/光谱行为之间的关系。配体中心自由基与高自旋金属中心之间的反铁磁耦合导致第一个还原电位的正向移动，并导致具有中等强度的价间电荷转移带的混合价物种。不同自旋态的差异扩展到配合物的电化学反应性：虽然低自旋物种是电催化 CO 还原的前催化剂，并导致 CO 的优先形成，法拉第效率为 37%，但高自旋物种仅在适度的法拉第效率（约 20%）下催化质子还原。
