Reversible CO Dissociation of Tricarbonyl Iodide [Fe]-Hydrogenase Models Ligating Acylmethylpyridyl Ligands

A combined experimental and computational investigation of the CO dissociation properties of three [Fe]-hydrogenase models, [(2-CH2CO-6-HOC5H3N)­Fe­(CO)3I] (1), [(2-CH2CO-6-MeOC5H3N)­Fe­(CO)3I] (2), and [(2-CH2CO-6-t-BuOC5H3N)­Fe­(CO)3I] (3), shows equilibria of tricarbonyl and dicarbonyl complexes in solution. In CH3CN, 1 transforms to the solvated product [(2-CH2CO-6-HOC5H3N)­Fe­(CO)2(CH3CN)­I] (7). The reactivity of 2 with PPh3 was also explored, giving [(2-CH2CO-6-MeOC5H3N)­Fe­(CO)2(PPh3)­I] (8) via one CO substitution by PPh3.