Tricarbonylrhenium(I) and manganese(I) complexes of 2-(pyrazolyl)-4-toluidine

Abstract

A series of tricarbonyl rhenium(I) and manganese(I) complexes of the electroactive 2-(pyrazolyl)-4-toluidine ligand, H(pzAn Me), has been prepared and characterized including by single crystal X-ray diffraction studies. The reactions between H(pzAn Me) and M(CO) 5Br afford fac-MBr(CO) 3[H(pzAn Me)] (M = Mn, 1a; Re, 1b) complexes. The ionic species { fac-M(CH 3CN)(CO) 3[H(pzAn Me)]}(PF 6) (M = Mn, 2a; Re, 2b) were prepared by metathesis of 1a or 1b with TlPF 6 in acetonitrile. Complexes 1a and 1b partly ionize to {M(CH 3CN)(CO) 3[H(pzAn Me)] +}(Br −) in CH 3CN but retain their integrity in less donating solvents such as acetone or CH 2Cl 2. Each of the four metal complexes reacts with (NEt 4)(OH) in CH 3CN to give poorly-soluble crystalline [ fac-M(CO) 3(μ-pzAn Me)] 2 (M = Mn, 3a; Re, 3b). The solid state structures of 3a and 3b are of centrosymmetric dimeric species with bridging amido nitrogens and with pyrazolyls disposed trans- to the central planar M 2N 2 metallacycle. In stark contrast to the diphenylboryl derivatives, Ph 2B(pzAn Me), none of the tricarbonyl group 7 metal complexes are luminescent.