Disulfide reductive elimination from an iron(iii) complex

Abstract

The redox-active pincer ligand derived from bis(3,5-di-tert-butyl-2-phenol)amine, [ONO^cat]H₃, enables reductive elimination of di-tert-butyldisulfide from a putative iron(III) dithiolate complex. The quinonate synthon of the ligand, [ONO^q]K, was used to prepare [ONO^q]FeX₂ complexes (1, X = Cl; 2, X = N(SiMe₃)₂), which were characterized by single-crystal X-ray diffraction, EPR and Mössbauer spectroscopies and identified to be high-spin iron(III) complexes. The protonolysis of 2 with tetrachlorocatechol afforded either monomeric [ONO^q]Fe(ortho-C₆O₂Cl₄)(py) (3) or dimeric {[ONO^q]Fe(ortho-C₆O₂Cl₄)}₂ (4). In contrast, the protonolysis of 2 with tert-butylthiol resulted in the extrusion of di-tert-butyldisulfide and the formation of a [ONO^cat]Fe fragment trapped with pyridine as monomeric [ONO^cat]Fe(py)₃ (5) or dimeric {[ONO^cat]Fe(py)}₂ (6). These results indicate that the [ONO]Fe platform can promote reductive elimination of disulfide without incurring changes to the metal oxidation state.