Abstract
The anionic mononuclear Mn-thiolate complexes [(thf)Mn(S,S-C6H3-R)2]– (R = H (1a), Me (1b) was assigned as a high spin d4 (Mn(III)) electronic structure based on EPR and SQUID analysis. Presumably, the role of tetrahydrofuran ligand coordinated to the Mn(III) center in complexes 1a/1b is to reimburse the electron deficiency of the Mn(III) center as well as to stabilize the Mn(III) oxidation level. The conversion of complexes 1a/1b to the stable dimeric [Mn(S,S-C6H3-R)2]2 2– (R = H (2a), Me (2b)) was displayed when CH2Cl2 solvent was added into complexes 1a and 1b at ambient temperature. Formation of complexes 2a/2b can be interpreted as coordinative association of two anionic mononuclear [Mn(S,S-C6H3-R)2]– in the absence of thf coordinating solvent. The electronic configuration of complexes 2a/2b was assigned as high spin d4 Mn(III) in a square pyramidal ligand field. Complex 2a/2b was reduced by [PPN][BH4] (or [Et4N][BH4]) to yield [Mn(S,S-C6H3-R)2] 2– (R = H (3a), Me (3b)). The electronic configuration of complexes 3a/3b was assigned as high spin d5 Mn(II) in a tetrahedral ligand field. Reaction of complexes 2a/2b and NO(g) afforded a discrete mononitrosyl-manganese [(NO)Mn(S,S-C6H3-R)2]– (R = H (4a), Me (4b)) assigned as the resonance hybrid of {MnIII-NO˙} and {MnII-NO+} electronic configuration in a square pyramidal ligand field. Complexes 3a/3b was nitrosylated to produce [(NO)Mn(S,S-C6H3-R)2] 2– (R = H (5a), Me (5b)). The {Mn(NO)}6 5a/5b was best described as the resonance hybrid of {MnIII-NO–} and {MnII-NO˙} electronic configuration in a square pyramidal ligand field. The complexes 5a/5b was oxidized to yield [Mn(S,S-C6H3-R)3] 2– (R = H (6a), Me (6b)). The electronic configuration of complexes 6a/6b was assigned as high spin d3 Mn(IV) in a distorted octahedral ligand field.