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]­(PF6)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 CoCl2·6H2O 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)]­(PF6)2 (2: L = 2,2′-bipy, 3: L = phen, 4: L = 2,9-dmphen), [Zn­(Tab)2(N-Meim)2]­(PF6)2 (5), [Zn­(Tab)2(bppy)]­(PF6)2 (6), [Co­(Tab)2(L)2]­(PF6)3 (7: L = 2,2′-bipy, 8: L = phen, 9: L = 4,4′-dmbpy), and [Co­(Tab)­(bdmppy)­Cl]­(PF6) (10). These compounds were characterized by elemental analysis, IR spectra, UV–vis spectra, 1H NMR, electrospray ionization (ESI) mass spectra, and single-crystal X-ray diffraction. The Zn­(II) in [Zn­(Tab)2Ln]2+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]3+ 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]2+ dication when it is attacked by L ligands, while in the cases of 7-9, the Zn­(II) of the [Zn­(Tab)4]2+ dication was replaced by Co­(III) (derived from oxidation of Co­(II) by O2) 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]2+ 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]2‑ unit of Zn-MTs with N-heterocyclic ligands and toxic metal ions encountered in a natural environment.