Iron Pyridine-2-thiolate Complexes:  Interconversion of [Fe⁰(CO)₄(SC₅H₄N)]^-, cis-[Fe^II(CO)₂(SC₅H₄N)₂], and [Fe^II(SC₅H₄N)₃]^-

Abstract

The reaction of bis(2-pyridyl) disulfide with [HFe(CO) 4 ]affords [Fe(CO) 4 (SC 5 H 4 N)] -, in which the pyridine-2-thiolate ligand is bound in a monodentate (Sbonded) mode. Oxidative addition of bis(2-pyridyl) disulfide to [Fe(CO) 4 (SC 5 H 4 N)]and concomitant displacement of [SC 5 H 4 N]leads to the neutral monomeric compound cis-[Fe(CO) 2 (SC 5 H 4 N) 2 ]. In the presence of [SC 5 H 4 N]in CH 3 CN at 60 °C, cis-[Fe(CO) 2 (SC 5 H 4 N) 2 ] undergoes facile conversion to d 6 Fe(II) high-spin [Fe(SC 5 H 4 N) 3 ] -. Reduction of cis-[Fe(CO) 2 (SC 5 H 4 N) 2 ] and [Fe(SC 5 H 4 N) 3 ]under CO at room temperature with [BH 4 ] -/[Na][benzophenone] affords the monodentate (Sbonded) complex [Fe(CO) 4 (SC 5 H 4 N)] -. The results are consistent with sulfur-donor atom stabilization of the lower oxidation states of iron, while the S,N-chelating pyridine-2-thiolate ligand enhances the stability of iron in the higher oxidation state.

The iron centre of the cluster-free hydrogenase (Hmd): low-spin Fe(ii) or low-spin Fe(0)?

“…To this end we have plotted the averages of the two infrared absorption bands for all complexes documented in the literature against the known iron oxidation state. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] z The left hand side of the plot shown in Fig. 3 shows the evident correlation between the observed oxidation states and the averages of the IR absorption bands.…”

Mononuclear Iron(II) Dicarbonyls Derived from NNS Ligands – Structural Models Related to a “Pre‐Acyl” Active Site of Mono‐Iron (Hmd) Hydrogenase

“…For example, Hu reported a structural [Fe]-H 2 ase model derived from 2-thiopyridine (pyS), namely, [(pyS)Fe{cis-(CO) 2 }(CH 3 CO)(CN)] -, [10] whereas Liaw and co-workers structurally characterized the related complexes [(pyS)Fe{cis-(CO) 2 }(trans-CN) 2 ] -and [(pyS) 2 Fe{cis-(CO) 2 }]. [19,20] The thiophene-derived complex [(bpy)(2TT) 2 Fe{cis-(CO) 2 }] (bpy = 2,2-bipyridine) was also reported. [21] -(carbamate) may also be reliably derived from thiocarboxylates.…”

A re-investigation of [Fe(l-cysteinate)2(CO)2]2−: an example of non-heme CO coordination of possible relevance to CO binding to ion channel receptors

“…It is unusual for an Fe II 39 [Fe(quinoline-2-thiolato-N,S) 2 (CO) 2 ], 40 [Fe(2-thiothiophene) 2 (bipy)(CO) 2 ], 41 and cis-[Fe(2-thiopyridine) 2 (CO) 2 ]. 42 Seven of these compounds have both nitrogens trans to CO as in 3, while [Fe(quinoline-2thiolato-N,S) 2 (CO) 2 ] has one N and one S trans to CO as in 5.…”