Protonation of a Biologically Relevant Cu-II mu-Thiolate Complex: Ligand Dissociation or Formation of a Protonated Cu-I Disulfide Species?

作者：Ording Wenker Erica C M; van der Plas Martijn; Siegler Maxime A; Guerra Celia Fonseca^*; Bouwman Elisabeth

来源：Chemistry - A European Journal, 2014, 20(51): 16913-16921.

DOI：10.1002/chem.201403918

• biomimetic synthesis
• coordination chemistry
• copper
• protonation
• redox chemistry

The proton-induced electron-transfer reaction of a Cu-II mu-thiolate complex to a Cu-I-containing species has been investigated, both experimentally and computationally. The Cu-II mu-thiolate complex [Cu-II 2(LMeS) 2] 2+ is isolated with the new pyridyl-containing ligand LMeSSLMe, which can form both Cu-II thiolate and Cu-I disulfide complexes, depending on the solvent. Both the Cu-II and the Cu-I complexes show reactivity upon addition of protons. The multivalent tetranuclear complex [Cu-I 2Cu(II) 2(LS) 2(CH3CN)(6)](4+) crystallizes after addition of two equivalents of strong acid to a solution containing the mu-thiolate complex [Cu-II (2)((LS)-S-Me)(2)](2+) and is further analyzed in solution. This study shows that, upon addition of protons to the Cu-II thiolate compound, the ligand dissociates from the copper centers, in contrast to an earlier report describing redox isomerization to a Cu-I disulfide species that is protonated at the pyridyl moieties. Computational studies of the protonated Cu-II mu-thiolate and Cu-I disulfide species with LSSL show that already upon addition of two equivalents of protons, ligand dissociation forming [Cu-I(CH3CN)(4)](+) and protonated ligand is energetically favored over conversion to a protonated Cu-I disulfide complex.

• 出版日期2014-12-15