Evaluation of Organic Hydride Donors as Reagents for the Reduction of Carbon Dioxide and Metal-Bound Formates

A variety of organic hydride donors (OHDs) have been tested as reagents for the transfer of hydride to iron formato complexes in the activation and reduction of carbon dioxide. Theoretical calculations show that the selection of OHD and solvent is crucial when planning systems involving OHD cooperativity. Strong consideration is given to the likelihood that metal centers may deactivate formate to hydride attack, since, in general, the formate group has more resonance stabilization energy when complexed to a metal center compared to an organoformate or formic acid. It is experimentally demonstrated that 1,2-dihydropyridine is not a competent reducing agent for carbon dioxide.

已有多种有机氢化物供体（organic hydride donors, OHDs）被用作氢化物转移试剂，应用于二氧化碳活化与还原过程中涉及甲酸铁配合物（iron formato complexes）的反应。理论计算表明，在设计涉及OHD协同作用的反应体系时，OHD与溶剂的选择至关重要。鉴于与金属中心配位的甲酸根基团，相较于有机甲酸酯或甲酸而言通常具有更高的共振稳定能，因此需重点考量金属中心可能会抑制甲酸根被氢化物进攻的可能性。实验证实，1,2-二氢吡啶并非二氧化碳的有效还原剂。