摘要
The preparation of the varieties of five-coordinate sixteen -electron manganese(I) complexes [Mn(CO) <sub>3</sub> (-EC <sub>6</sub> H <sub>4</sub> -o-E′-)] <sup>-</sup> (E = Te, Se, S, O; E′ = NH, S, O) by (a) oxidative addition of 2-aminophenyl dichalcogenides to anionic manganese(0)-carbonyl, (b) π-donating ligand metathesis reaction of complex [Mn(CO) <sub>3</sub> (-TeC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> , and (c) reduction/deprotonation of the neutral dimetallic [(Mn(CO) <sub>3</sub> ) <sub>2</sub> (μ-SC <sub>6</sub> H <sub>4</sub> -o-S-S-C <sub>6</sub> H <sub>4</sub> -o-μ-S-)]/[(CO) <sub>3</sub> Mn (μ-SC <sub>6</sub> H <sub>4</sub> -o-NH <sub>2</sub> -)] <sub>2</sub> proved successful approaches in this direction. The IR ν <sub>co</sub> data of the coordinatively and electronically unsaturated [Mn(CO) <sub>3</sub> (-EC <sub>6</sub> H <sub>4</sub> -o-E′-)] <sup>-</sup> (E = Te, Se, S, O; E′ = NH, S, O) complexes suggest the relative order of π-donating ability of the series of bidentate ligands being [TeC <sub>6</sub> H <sub>4</sub> -o-NH] <sup>2-</sup> > [SeC <sub>6</sub> H <sub>4</sub> -o-NH] <sup>2-</sup> > [SC <sub>6</sub> H <sub>4</sub> -o-NH] <sup>2-</sup> > [SC <sub>6</sub> H <sub>4</sub> -o-S] <sup>2-</sup> > [SC <sub>6</sub> H <sub>4</sub> -o-O] <sup>2-</sup> > [OC <sub>6</sub> H <sub>4</sub> -o-O] <sup>2-</sup> . Proton NMR spectra of the [Mn(CO) <sub>3</sub> (-EC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> (E =Te, Se, S) derivatives show the low-field shift of the amide proton ( <sup>1</sup> H NMR (C <sub>4</sub> D <sub>8</sub> O): δ 9.66 (br) ppm (E = Te), 9.32 (br) ppm (E = Se), 8.98 (br) ppm (E = S)). The formation of the dimetallic [(CO) <sub>3</sub> Mn(μ-SC <sub>8</sub> N <sub>2</sub> H <sub>4</sub> -o-S-)] <sub>2</sub> <sup>2-</sup> can be interpreted as coordinative association of two units of unstable mononuclear [(CO) <sub>3</sub> Mn(-SC <sub>8</sub> N <sub>2</sub> H <sub>4</sub> -o-S-)] <sup>-</sup> and reflects the π-donating ability of the bidentate ligand is responsible for the formation of pentacoordinate, sixteen-electron manganese(I) carbonyl complexes. The neutral bimetallic manganese(I)-bismercaptophenyl disulfide complex [(Mn(CO) <sub>3</sub> ) <sub>2</sub> (μ-SC <sub>6</sub> H <sub>4</sub> -o-S-S-C <sub>6</sub> H <sub>4</sub> -o-μ-S-)] with internal S-S bond length of 2.222(1) Å and the five-coordinate sixteen-electron complex [Mn(CO) <sub>3</sub> (-SC <sub>6</sub> H <sub>4</sub> -o-S-)] <sup>-</sup> are chemically interconvertible. In a similar fashion, treatment of complex [Mn(CO) <sub>3</sub> (-SC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> with HBF <sub>4</sub> yielded neutral dinuclear complex [(CO) <sub>3</sub> Mn(μ-SC <sub>6</sub> H <sub>4</sub> -o-NH <sub>2</sub> -)] <sub>2</sub> and showed that the amine deprotonation is reversible. Investigations of π-donating ligand metathesis reactions of complex [Mn(CO) <sub>3</sub> (-TeC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> revealed that the stable intermediate, not the π-donating ability of bidentate ligands, is responsible for the final protonation/oxidation product. This argument is demonstrated by reaction of [Mn-(CO) <sub>3</sub> (-TeC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> with 1,2-benzenedithiol, hydroxythiophenol, and catechol, respectively leading to the formation of [Mn(CO) <sub>3</sub> (-EC <sub>6</sub> H <sub>4</sub> -o-E′-)] <sup>-</sup> (E = S, O; E′ = S, O), although any π-donor containing the amido group is a more effective donor than any other π-donor lacking an amido group. Also, the reactions of [Mn(CO) <sub>3</sub> (-TeC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> with electrophiles occurring at the more electron-rich amide site support that the more electron-rich amide donor of the chelating 2-tellurolatophenylamido occupies an equatorial site as indicated by a shorter Mn <sup>1</sup> -N bond length of the distorted trigonal bipyramidal [Mn(CO) <sub>3</sub> (-TeC <sub>6</sub> H <sub>4</sub> -o-NH-)] <sup>-</sup> .