Catalytic reactivity of an iridium complex with a proton responsive N-donor ligand in CO hydrogenation to formate.

Catalytic hydrogenation of CO into formic acid/formate is an attractive conversion in the utilization of CO. Although various catalysts with high catalytic efficiency are reported, a very few studies have been carried out to correlate/understand the efficacy and stability of the hydrogenation catalysts, which could be helpful to direct the future design strategy of corresponding catalysts. Herein, a half-sandwich iridium complex containing bibenzimidazole as a proton responsive N-donor ligand, [Cp*Ir(BiBzImH)Cl]Cl, has been synthesized and fully characterized.

Bis(μ-4,4''-difluoro-1,1':3',1''-terphenyl-2'-carboxylato-κ(2)O:O')bis[aqua(4,4''-di-fluoro-1,1':3',1''-terphenyl-2'-carboxyl-ato-κO)(pyridine-κN)cobalt(II)] diethyl ether disolvate.

The structure of the title compound, [Co(2)(C(19)H(11)F(2)O(2))(4)(C(5)H(5)N)(2)(H(2)O)(2)]·2C(4)H(10)O, comprises two Co(II) atoms in a distorted square pyramidal coordination environment, straddling a crystallographic inversion center with a Co⋯Co separation of 3.1923 (15) Å. Each Co(2+) cation is coordinated by three O atoms of three 4,4''-difluoro-1,1':3',1''-terphenyl-2'-carboxyl-ate ligands, one water O atom and one pyridine N atom, forming a CoO(4)N polyhedron.