New Pentadentate Carboxylate‐Derivatized Sulfur Ligands Affording Water Soluble Iron Complexes with [Fe(NS₄)] Cores that Bind Small Molecules (CO, NO, PMe₃) as Co‐Ligands

Redox Interconversion between Cobalt(III) Thiolate and Cobalt(II) Disulfide Compounds

“…Fe2 is bound to two chloride ions and three nitrogen donors of the ligand in a pseudo-square-pyramidal geometry with a τ value of 0.25; also, in this case the three nitrogen donors are bound in a meridional fashion in the equatorial plane of the square pyramid. The Fe1–S1 bond length is 2.6925(8) Å, which is much shorter than the Fe2–S2 distance of 3.231(1) Å but longer than the Fe–S bond distances in some reported thioether-Fe­(II) compounds (ranging from 2.200 to 2.285 Å). − The Fe–N bond distances range from 2.135(2) to 2.270(3) Å for both Fe II ions, in agreement with a high-spin state ( S = 2) of both iron­(II) centers. One of the two lattice methanol molecules is hydrogen bound to one of the coordinated chloride ions.…”

Tetra‐ and Decanuclear Iron(II) Complexes of Thiacalixarene Macrocycles: Synthesis, Structure, Mössbauer Spectroscopy and Magnetic Properties

“…[47][48][49][50][51][52][53][54] The Fe II -S bond lengths are longer than the few previously reported for thioether complexes of high-spin iron(ii) (2.20-2.29 Å). [55] This should be due to the rigidity of the macrocycle, which does not allow the sulfur atoms to come closer to the iron(ii) ions. Careful analysis of the interatomic distances and angles around the iron(ii) ions reveals that the coordination polyhedrons are distorted trigonal-prismatic, as shown in Figure 2.…”

Development of parameter sets for semi-empirical MO calculations of transition metal systems: Iron parameters for iron–sulfur proteins

“…We turn now to a consideration of the model compounds I-VI, involving the Fe(pyS 4 ) core (see Fig. 2) [25]. In Table 6, we show a comparison of the experimental Fe-X bond lengths with the values predicted by the two different density-functionals and by PM3.…”

“…A range of complexes involving the binding of the [Fe(pyS 4 )] fragment to various small ligands [e.g. CO, N 2 H 2 , N 2 H 4 , NH 3 , C 6 H 5 N and P(CH 3 ) 3 ], have recently been prepared in which there are two Fe-X interactions in addition to the four Fe-S interactions [25]. These latter complexes are also redox-active, which strengthens their case to be studied as redox-active site analogues.…”