Reactions of Rh₂(CH₃COO)₄ with thiols and thiolates: a structural study

Area of Science:

• Inorganic Chemistry
• Materials Science
• Spectroscopy

Background:

• Dirhodium(II) tetracarboxylates are versatile compounds with diverse reactivity.
• Understanding their interactions with sulfur-containing molecules is crucial for various applications.

Purpose of the Study:

• To investigate the structural differences in aerobic reaction products of Rh2(AcO)4 with thiols and thiolates.
• To elucidate the impact of these reactions on the dirhodium framework.

Main Methods:

• X-ray absorption spectroscopy to probe structural changes.
• Time-dependent density functional theory (TD-DFT) calculations for spectral analysis.
• Utilized ethanethiol, dihydrolipoic acid (DHLA), and their sodium thiolate salts.

Main Results:

• Coordination of thiols to Rh2(AcO)4 forms Rh-SH bonds, maintaining the RhII-RhII bond and causing a color change.
• Reaction with sodium thiolates in the presence of O2 breaks the Rh2(AcO)4 framework, forming oligomeric chains of Rh(III) ions bridged by sulfur.
• Structural data for Rh(III) chains are comparable to those from reactions in aqueous media.

Conclusions:

• The reaction pathway of dirhodium(II) tetracarboxylates with sulfur ligands depends significantly on whether thiols or thiolates are used.
• The findings provide insights into potential interactions with cysteine-rich biomolecules like metallothioneins.