Iron(I)‐Based Carbonyl Complexes with Bridging Thiolate Ligands as Light‐Triggered CO Releasing Molecules (photoCORMs)

Abstract

A series of thiolate ligands were used to synthesize diiron(I) hexacarbonyl bis(thiolates) for structural studies. Conversion of the corresponding thiols with triiron(0) dodecacarbonyl yields complexes of the type [{(CO)3Fe(μ‐SR)}2] [R = C6H5 (1), C6H4‐4‐CH3 (2), C6H4‐4‐F (3), C6F5 (4), C6H4‐4‐CF3 (5), C6H2‐2,4,6‐(CH3)3 (6), CH2–C6H4‐4‐Cl (7)]. These complexes were isolated and fully characterized, including X‐ray crystal structures of complexes 2–7. The bridging thiolate ligands mainly influence the Fe–CO bond which is trans‐positioned to the second iron(I) center. In solution, the anti‐isomer with one axially and one equatorially oriented thiolate is the major species; severe steric strain induced by mesityl groups only allows the formation of syn‐endo‐isomeric molecules of 7. Furthermore, light‐induced CO release at solid material at the three representative complexes 1, 3, and 6 verify suitability as photoCORMs.