An electrochemically controlled release of NHCs using iron bis(dithiolene) N-heterocyclic carbene complexes

Abstract

A series of five coordinated [Fe(NHC)(S2C2R2)2] complexes were isolated and subjected to electrochemical reduction for the facile release of NHCs in the catalytic media.

Bis[1,3-bis(2,4,6-trimethylphenyl)imidazolium] bis(μ-cis-1,2-diphenylethene-1,2-dithiolato-κ2 S,S′:κS)bis[(cis-1,2-diphenylethene-1,2-dithiolato-κ2 S,S′)iron(III)] dimethylformamide disolvate

“…Despite their facile redox processes, the solid-state structure of the chemically reduced species [Fe(S 2 C 2 Ph 2 ) 2 ] 2 À have not yet been reported. Recently, we reported several five-coordinate iron bis(dithiolene) complexes with N-heterocyclic carbene ligands [Fe(S 2 C 2 Ph 2 ) 2 (NHC)] [NHC = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene; Selvakumar et al, 2021]. Under electrochemical conditions, these complexes undergo two successive one-electron reductions, with the first reduction being reversible whereas the second reduction is irreversible.…”

“…Under electrochemical conditions, these complexes undergo two successive one-electron reductions, with the first reduction being reversible whereas the second reduction is irreversible. This irreversibility is attributed to the cleavage of the coordination of the N-heterocyclic carbene ligand to the respective iron atom (Selvakumar et al, 2021). To isolate and study the solid-state structure of [Fe(S 2 C 2 Ph 2 ) 2 NHC] À , we reduced the neutral complex [Fe(S 2 C 2 Ph 2 ) 2 (NHC)] with a stoichiometric amount of cobaltocene.…”

Two-Electron-Induced Reorganization of Cobalt Coordination and Metal–Ligand Cooperative Redox Shifting Co(I) Reactivity toward CO2 Reduction

“…Recent research on transition metal complexes has shown promising pathways in treating the gas via organometallic and electrochemical methods . The main strategies in using metal complexes include the modulation of redox potentials or stabilizing intermediates by the secondary coordination sphere; CO 2 electrocatalysis by porphyrin, − cyclam, − dithiolene, − and polypyridyl − complexes are well-known examples. Typical electron-transfer systems disfavor large structural distortion, yet electron-coupled reorganization can grant complexes a new CO 2 reactivity.…”

N-Heterocyclic Carbene Iron Complexes as Anticancer Agents: In Vitro and In Vivo Biological Studies

“…Despite the intensive research on iron complexes as possible anticancer drugs, the medicinal potential of Fe–NHC complexes has remained almost unexplored [ 31 ]. However, it has been proved that NHC ligands can be very useful for the stabilisation of iron organometallic complexes [ 32 , 33 , 34 ].…”