CoII Complexes with Mixed Amino-N and Thiolato-S Donor Sets − Structural Characterization and Electronic Properties of a Stable Bis(μ-thiolato)-Bridged Binuclear CoII Complex

Abstract

Keywords: Cobalt / S ligands / Electrochemistry / Raman spectroscopy / N ligandsTwo different ligands [S 2 N 3 py ] and [S 2 N 2 ], prepared from 2,6bis[1-(2-mercaptoanilino)ethyl]pyridine and 2,3-bis(2-mercaptoanilino)butane, respectively, have been used to investigate cobalt coordination with mixed amine nitrogen/sulfur donor sets. The pentadentate [S 2 N 3 py ] ligand gave rise to a mononuclear [Co II (S 2 N 3 py )] complex, which was found to be stable only at low temperatures under argon, and was characterized as having a high-spin Co II state on the basis of 1 H NMR and EPR measurements. In contrast, the tetradentate [S 2 N 2 ] ligand led to a binuclear bis(µ-thiolato) [Co II (S 2 N 2 )] 2 complex, the structure of which was solved by X-ray crystallography. Each Co II centre was found to reside in an N 2 S 3 square-pyramidal environment in the crystal, the two Co atoms being bridged by one of the two thiolates of an [S 2 N 2 ] ligand. On the basis of the temperature dependence of the magnetic susceptibility, the two Co II centres were found to be in a low-spin state and slightly antiferromagnetically coupled with an absolute J value of less than 3 cm −1 . In aerated [a]

Unprecedented Inequivalent Metal Coordination Environments in a Mixed‐Ligand Dicobalt Complex

“…The shift to lower energy for the S → Co2 band stems from the stabilization of the e g orbitals of Co2 by the two Me 2 bpy ligands (Figure ). After reduction by one electron, a new “sharp” peak appears at about 650 nm, which is assigned as S → Co2 LMCT as previously reported in mixed‐valence Co III /Co II species, and which sits adjacent to the S → Co1 LMCT that is retained in the one‐electron reduced complex.…”

Metallodithiolates as Ligands in Coordination, Bioinorganic, and Organometallic Chemistry

“…79,80 The N 2 S 2 ligand in which the N to S linker is a phenylene is found in complexes 71 and 72. 81,82 The stick drawings of these complexes indicate similarity to the alkyl chain N 2 S 2 ligands; however, the non-innocence of such 2-aminothiophenolate units has shown these ligands are actually [N 2 S 2 ] 3− radicals bound to Fe 2+ in 71; in 72, the [N 2 S 2 ] 2− diradical is bound to low-spin Co 2+ . Anti-ferromagnetic coupling accounts for the lack of an EPR signal in complex 72.…”

Dinuclear cobalt and manganese squarate complexes with bidentate N-donor ligand: syntheses, crystal structures, spectroscopic, thermal and voltammetric studies

“…The cyclic voltammogram of (1) exhibits metal centred three quasi-reversible waves, located at E 1/2 = )1.28 V, E 1/2 = )0.86 V and E 1/2 = 0.09 V [47,48]. Remaining waves correspond to two successive monoelectronic oxidation-reduction of the squarate dianion (SQ 2) ).…”