Boden Pit J, Di Martino-Fumo Patrick, Bens Tobias, Steiger Sophie T, Marhöfer Daniel, Niedner-Schatteburg Gereon, Sarkar Biprajit
Department of Chemistry and State Research Center Optimas, TU Kaiserslautern, Erwin-Schrödinger-Straße 52, 67663, Kaiserslautern, Germany.
Chair of Inorganic Coordination Chemistry, Institute of Inorganic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Chemistry. 2022 Sep 12;28(51):e202201038. doi: 10.1002/chem.202201038. Epub 2022 Jul 13.
This work tackles the photochemistry of a series of mononuclear Cr , Mo and W carbonyl complexes containing a bidentate mesoionic carbene ligand of the 1,2,3-triazol-5-ylidene type. FTIR spectroscopy, combined with density functional theory calculations, revealed a clean photo-induced reaction in organic solvents (acetonitrile, pyridine, valeronitrile) to give mainly one photoproduct with monosubstitution of a carbonyl ligand for a solvent molecule. The highest photodissociation quantum yields were reached for the Cr complex under UV irradiation (266 nm). Based on previous investigations, the kinetics of the dark reverse reactions have now been determined, with reaction times of up to several hours in pyridine. Photochemical studies in the solid state (KBr matrix, frozen solution) also showed light-induced reactivity with stabilization of the metastable intermediate with a free coordination site at very low temperature. The identified reactive species emphasizes a mechanism without ligand-sphere reorganization.
这项工作研究了一系列含有1,2,3 - 三唑 - 5 - 亚基型双齿中氮茚卡宾配体的单核铬、钼和钨羰基配合物的光化学。傅里叶变换红外光谱结合密度泛函理论计算表明，在有机溶剂（乙腈、吡啶、戊腈）中发生了清晰的光诱导反应，主要生成一种光产物，其中一个羰基配体被一个溶剂分子单取代。在紫外光（266 nm）照射下，铬配合物的光解离量子产率最高。基于先前的研究，现已确定了暗态逆反应的动力学，在吡啶中的反应时间长达数小时。固态（KBr基质、冷冻溶液）光化学研究也表明，在非常低的温度下，光诱导反应会使具有自由配位点的亚稳中间体稳定化。所确定的活性物种强调了一种无需配体球重组的机制。
