Reactions of the cationic zinc thiolate model complex [Zn(Tab)4](PF6)2 with N-donor ligands and cobalt dichloride.

Reactions of Zn(Tab)(4)(2) (Tab = 4-(trimethylammonio)benzenethiolate) (1) with 2,2'-bipyridine (2,2'-bipy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (2,9-dmphen), N-methylimidazole (N-Meim), and 2,6-bis(pyrazol-3-yl)pyridine (bppy) or with CoCl(2)·6H(2)O at the presence of N-donor ligands (2,2'-bipy, phen, 4,4'-dimethyl-2,2'-bipyridine (4,4'-dmbpy), 2,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)pyridine (bdmppy))gave rise to a family of zinc or cobalt thiolate complexes, Zn(Tab)(2)(L)(2) (2: L = 2,2'-bipy, 3: L = phen, 4: L = 2,9-dmphen), Zn(Tab)(2)(N-Meim)(2)(2) (5), Zn(Tab)(2)(bppy)(2) (6), Co(Tab)(2)(L)(2)(3) (7: L = 2,2'-bipy, 8: L = phen, 9: L = 4,4'-dmbpy), and Co(Tab)(bdmppy)Cl (10). These compounds were characterized by elemental analysis, IR spectra, UV-vis spectra,(1)H NMR, electrospray ionization (ESI) mass spectra, and single-crystal X-ray diffraction. The Zn(II) in Zn(Tab)(2)L(n)dications of 2-5 is tetrahedrally coordinated by two Tab ligands and one L or two N-Meim ligands. In 6, the Zn(II) has a distorted trigonal-bipyramidal geometry, coordinated by two Tab ligands and one tridentate bppy ligand. The Co(III) in the Co(Tab)(2)(L)(2) trications of 7-9 is octahedraly chelated by two bidentate L ligands and two Tab ligands. In 10, the Co(II) adopts a distorted trigonal-bipyramidal geometry, coordinated by one Cl(-), one Tab ligand, and one tridentate bdmppy. In the formation of 2-6, two Tab ligands are removed from the Zn(Tab)(4) dication when it is attacked by L ligands, while in the cases of 7-9, the Zn(II) of the Zn(Tab)(4) dication was replaced by Co(III) (derived from oxidation of Co(II) by O(2)) followed by the removal of two Tab ligands via L ligands. In the case of 10, the central Zn(II) of the Zn(Tab)(4) dication was displaced by Co(II) followed by the removal of three Tab ligands via one Cl(-) and one tridentate bdmppy. These ligand and metal replacement reactions may provide some interesting information on the interactions of the Zn(S-Cys)(4) unit of Zn-MTs with N-heterocyclic ligands and toxic metal ions encountered in a natural environment.