Palladium(II) Ion Mediated Disulfide/Thiolate Interconversion: Predicting the Disulfide Group State from First...

Area of Science:

• Coordination Chemistry
• Computational Chemistry
• Biochemistry

Background:

• Previous studies reported differing reactivity of homologous disulfides with palladium(II) (Pd²⁺).
• Reactions include stepwise complexation or disproportionation into thiolate and sulfinic acid complexes.
• The underlying reasons for these distinct reactivity patterns remained unclear.

Purpose of the Study:

• To computationally investigate the disulfide/thiolate interconversion of four homologous disulfides with Pd²⁺ in aqueous solution.
• To elucidate the role of stabilizing intermediate S,S'-binuclear complexes in dictating reactivity.
• To develop a theoretical model explaining the experimentally observed reactivity differences.

Main Methods:

• Computational investigation of disulfide ligand interactions with Pd²⁺.
• Analysis of the stabilization of proposed S,S'-binuclear complex intermediates.
• Theoretical modeling to rationalize experimental observations.

Main Results:

• Different homologous disulfides exhibit varying capacities to stabilize key S,S'-binuclear complex intermediates.
• This stabilization difference directly correlates with the observed distinct reactivity patterns (complexation vs. disproportionation).
• A theoretical model was developed that successfully rationalizes these reactivity differences.

Conclusions:

• The ability of homologous disulfides to stabilize Pd²⁺-mediated binuclear complexes is the key factor governing their reactivity.
• This study provides a theoretical framework for understanding the diverse reactions of disulfides with nonredox metal cations.
• The findings offer insights into the coordination chemistry of disulfides and their interactions with transition metals.