Hydrosulfide (HS⁻) Coordination in Iron Porphyrinates

Abstract

Recent reports of potential physiological roles of hydrogen sulfide have prompted interest in hemesulfide interactions. Heme-H 2 S and/or heme-HS − interactions could potentially occur during endogenous production, transport, signaling events, and catabolism of H 2 S. We have investigated the interaction of the hydrosulfide ion (HS − ) with iron porphyrinates. UV-vis spectral studies show the formation of [Fe(Por) . Characterization by single-crystal Xray analysis, mass spectrometry, and Mössbauer and IR spectroscopy are all consistent with that of known sulfur-bound high-spin iron(II) compounds. The Fe-S distances of 2.3929(5) and 2.3887(13) Å are longer than all reported values of [Fe II (Por)(SR)] − species. An analysis of porphyrin nonplanarity for these derivatives and for all five-coordinate high-spin iron(II) porphyrinate derivatives with an axial anion ligand is presented. In our hands, attempts to synthesize iron(III) HS − derivatives led to iron(II) species.

Sulfide Oxidation by a Noncanonical Pathway in Red Blood Cells Generates Thiosulfate and Polysulfides

“…We propose that [1] is in equilibrium with HS ⅐ -Fe II Hb [2]. The latter is also proposed as an intermediate for the sulfide-carrying Hb from L. pectinata (29), and its feasibility is supported by model studies showing that HS Ϫ ligation to ferric porphyrinate generates the corresponding Fe II derivative (30). In principle, the ferrous heme-bound HS ⅐ radical could react with O 2 to form SO 2 .…”

Hydrogen Sulfide and Hemeproteins: Knowledge and Mysteries

“…As in HbI, strong hydrogen bond interactions between the hemeproteins and the bound H 2 S can facilitate rapid deprotonation of H 2 S, stimulating formation of an Fe II -SHÁ intermediate by one electron transfer from the Fe III -SH À species. Reduction of the heme by the Fe III -SH À species is supported by the fact that in model porphyrinate systems, coordination of HS À to ferric iron produces Fe II high spin derivatives (58). In the presence of a slight excess of H 2 S, the latter can react with the Fe II -SHÁ radical intermediate producing deoxy heme Fe II and a …”

A Copper Porphyrin for Sensing H2S in Aqueous Solution via a “Coordinative‐Based” Approach

“…In particular, we employed myoglobin from horse skeletal muscle (Mb). [44] A limitation of our Mb monitoring system was the low fluorescence enhancement in the presence of an excess of H 2 S. Furthermore, with the addition of H 2 [45] Aiming at overcoming some of the limitations of our Mb-based H 2 S sensing system we used cobalt containing peptide deformylase (Co-PDF) for implementation in a H 2 S sensor by the same coordinative-based approach. [46] The Co-PDF system operates as a "turn-off " devise, which is a limitation for real applications.…”