title: Thermodynamics of the Cu(II) μ-thiolate and Cu(I) disulfide equilibrium: a combined experimental and theoretical study.
abstract: The redox equilibrium between dinuclear Cu(II) μ-thiolate and Cu(I) disulfide structures has been analyzed experimentally and via DFT calculations. Two new ligands, L(2)SSL(2) and L(4)SSL(4), and their Cu(II) μ-thiolate and Cu(I) disulfide complexes were synthesized. For L(2)SSL(2), these two redox-isomeric copper species are shown to be in equilibrium, which depends on both temperature and solvent. For L(4)SSL(4) the μ-thiolate species forms as the kinetic product and further evolves into the disulfide complex under thermodynamic control, which creates the unprecedented possibility to compare both species under the same reaction conditions. The energies of the μ-thiolate and disulfide complexes for two series of related ligands have been calculated with DFT; the results rationalize the experimentally observed structures, and emphasize the important role that steric requirements play in the formation of the Cu(II) thiolate structure.
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University , P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: Erica C M
authors.initials: EC
authors.lastname: Ording-Wenker
authors.forename: Martijn
authors.initials: M
authors.lastname: van der Plas
authors.forename: Maxime A
authors.initials: MA
authors.lastname: Siegler
authors.forename: Sylvestre
authors.initials: S
authors.lastname: Bonnet
authors.forename: F Matthias
authors.initials: FM
authors.lastname: Bickelhaupt
authors.forename: Célia
authors.initials: C
authors.lastname: Fonseca Guerra
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Bouwman
mesh_terms: D003300:Copper / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D011789:Quantum Theory; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D004220:Disulfides; D008024:Ligands; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D003300:Copper