As a contribution to the valorization of carbon dioxide, new N,O-coordinated Ir(III), Rh(III), Ru(II), and Os(II) half-sandwich complexes have been designed, synthesized, and applied as homogeneous pre-catalysts in the experiments for direct and indirect CO₂ hydrogenation under basic conditions. The complexes contain a N,O-donor Schiff base ligand derived from N-(β-naphthyl)-2-oxy-1-naphthaldimine that assisted by partitioning the catalysts to the organic layer in biphasic mixtures, enabling catalyst separation. In the presence of DBU, the Os(II) half-sandwich complex N,O-Os(II) (C2) gave a TON of 889 for [DBUH][HCO₂] formation under a partial pressure of 60 bar CO₂/H₂ at 120 °C over 48 h, assisted by heterogeneous side reactions. Complexes N,O-Rh(III) (C3) and N,O-Ir(III) (C4) exhibited great efficiency in the homogeneous hydrogenation of carbon dioxide to afford formate and N,N-diethylformamide in the presence of DBU and diethylamine, respectively. Group 9 half-sandwich complexes eminently qualify as useful in the direct and indirect hydrogenation of CO₂ to afford reaction intermediates that can be used to make carbon-neutral fuel.

为促进二氧化碳的增值，已设计，合成和应用了新的N，O配位的Ir（III），Rh（III），Ru（II）和Os（II）半三明治复合物。在碱性条件下进行直接和间接CO ₂加氢的实验中的预催化剂。该配合物包含衍生自N-（β-萘基）-2-氧基-1-萘二胺的N，O-施主席夫碱配体，其通过将催化剂分配到两相混合物中的有机层中而辅助进行催化剂分离。在DBU的存在下，Os（II）半三明治复合物N，O -Os（II）（C2）的[DBUH] [HCO ₂ ]值为889。在60 bar CO ₂ / H ₂的分压下于120°C在48 h内通过异质副反应的形成。配合物N，O -Rh（III）（C3）和N，O -Ir（III）（C4）在DBU和二乙胺存在下，在二氧化碳的均相加氢中提供甲酸和N，N-二乙基甲酰胺，显示出很高的效率， 分别。第9组半三明治复合物非常适合在直接和间接CO ₂氢化中使用，以提供可用于生产碳中性燃料的反应中间体。