Trivalent iron and ruthenium complexes with a redox noninnocent (2-mercaptophenylimino)-methyl-4,6-di-tert-butylphenolate(2-) ligand.
The 3,5-di-tert-butyl substituted N-(salicylidene)-o-mercaptoaniline (H(2)L) ligand reacted with equimolar amounts of FeBr(2) and 2 equiv of triethylamine in air affords [Fe(III)(L-L)Br](0) (1), where (L-L)(2-) is a pentacoordinate ligand formed from the oxidative dimerization of L(2-) via disulfide bridge formation. Reaction of H(2)L with RuCl(3) x H(2)O and NEt(3) gives a dark green-brown dinuclear complex, [Ru(III)(2)(L)(2)Cl(2)(NCCH(3))(2)](0) (2). Both complexes have been characterized by X-ray crystallography. A Ru-Ru single bond is evident in 2. Complex 1 has also been characterized by electron paramagnetic resonance and Mossbauer spectroscopies and magnetic susceptibility measurements that identify a high-spin Fe(III) (S = (5)/(2)) center. Diamagnetic 2 is successively twice reversibly one-electron oxidized to produce [Ru(III)(2)(L(*))(L)Cl(2)(NCCH(3))(2)](+), [2](+) (S = (1)/(2)), and [Ru(III)(2)(L(*))(2)Cl(2)(NCCH(3))(2)](2+), [2](2+) (S = 0). Spectroelectrochemical and electron paramagnetic resonance measurements identify these as ligand-based oxidations affording o-coordinated phenoxyl radicals. DFT calculations on the electron transfer series corroborate this result and that the Ru-Ru single bond is retained throughout this series.
Roy
Nabarun
N
Max-Planck-Institut für Bioanorganische Chemie, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany.
Sproules
Stephen
S
Weyhermüller
Thomas
T
Wieghardt
Karl
K
D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D007501:Iron / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010636:Phenols / Q000138:chemical synthesis / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry*
C540952:(2-mercaptophenylimino)-methyl-4,6-di-tert-butylphenolate(2-); D008024:Ligands; D009942:Organometallic Compounds; D010636:Phenols; D013438:Sulfhydryl Compounds; D012428:Ruthenium; D007501:Iron