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Hydrosulfide (HS-) coordination in iron porphyrinates
Jeffrey W Pavlik1, Bruce C Noll, Allen G Oliver
1Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Inorganic Chemistry
|December 30, 2009
Summary
This study explores how hydrosulfide ions (HS(-)) interact with iron porphyrinates, synthesizing novel iron(II) porphyrin compounds. The findings reveal unique Fe-S bond characteristics and porphyrin structures relevant to heme-sulfide interactions.
Area of Science:
- Bioinorganic Chemistry
- Coordination Chemistry
- Spectroscopy
Background:
- Recent research highlights potential physiological roles of hydrogen sulfide (H₂S).
- Understanding heme-sulfide interactions is crucial for comprehending H₂S metabolism and signaling.
- Iron porphyrinates are key models for heme proteins.
Purpose of the Study:
- To investigate the interaction of hydrosulfide ion (HS⁻) with iron porphyrinates.
- To synthesize and characterize novel HS⁻-bound iron(II) porphyrin complexes.
- To analyze the structural and spectral properties of these complexes and their implications for heme-sulfide chemistry.
Main Methods:
- UV-vis spectroscopy for binding studies and complex formation.
- Synthesis of HS⁻-bound iron(II) porphyrin compounds.
- Single-crystal X-ray analysis, mass spectrometry, Mossbauer, and IR spectroscopy for characterization.
Main Results:
- Formation of mono- and bis-HS⁻ complexes with iron porphyrinates observed via UV-vis spectroscopy.
- Successful synthesis of the first HS⁻-bound iron(II) porphyrin compounds.
- Characterization confirmed HS⁻ binding to iron(II), with unusually long Fe-S bond distances.
- Analysis of porphyrin nonplanarity in relation to axial ligand binding.
Conclusions:
- The study provides the first direct evidence and characterization of HS⁻ binding to iron(II) porphyrinates.
- The synthesized compounds offer insights into heme-sulfide interactions relevant to biological systems.
- The observed structural features, particularly the Fe-S bond length, contribute to understanding sulfur coordination in heme chemistry.
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