A mononuclear octahedral cobalt( ii ) complex based on a unique benzothiadiazole- ortho -vanillin ligand shows slow relaxation of the magnetization under applied dc magnetic fields.

Six-coordinated nickel(ii) complexes based on benzothiadiazole-salicylaldehyde and -ortho-vanillin ligands have been structurally characterized and their magnetic properties investigated.

Three 2,1,3-benzothiadiazole-based ligands decorated with two pyridyl groups, 4,7-di(2-pyridyl)-2,1,3-benzothiadiazol (2-PyBTD), 4,7-di(3-pyridyl)-2,1,3-benzothiadiazol (3-PyBTD) and 4,7-di(4-pyridyl)-2,1,3 benzothiadiazol (4-PyBTD), generate Zn^II and Ag^I complexes with a rich structural variety: [Zn(hfac)₂(2-PyBTD)] 1, [Zn₂(hfac)₄(2-PyBTD)] 2, [Ag(CF₃SO₃)(2-PyBTD)]₂3, [Ag(2-PyBTD)]₂(SbF₆)₂4, [Ag₂(NO₃)₂(2-PyBTD)(CH₃CN)] 5, [Zn(hfac)₂(3-PyBTD)] 6, [Zn(hfac)₂(4-PyBTD)] 7, [ZnCl₂(4-PyBTD)₂] 8 and [ZnCl₂(4-PyBTD)] 9 (hfac = hexafluoroacetylacetonato). The nature of the resulting complexes (discrete species or coordination polymers) is influenced by the relative position of the pyridyl nitrogen atoms, the nature of the starting metal precursors, as well as by the synthetic conditions. Compounds 1 and 8 are mononuclear and 2, 3 and 4 are binuclear species. Compounds 6, 7 and 9 are 1D coordination polymers, while compound 5 is a 2D coordination polymer, the metal ions being bridged by 2-PyBTD and nitrato ligands. The solid-state architectures are sustained by intermolecular π–π stacking interactions established between the pyridyl group and the benzene ring from the benzothiadiazol moiety. Compounds 1, 2, 7–9 show luminescence in the visible range. Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TD-DFT) calculations have been performed on the Zn^II complexes 1 and 2 in order to disclose the nature of the electronic transitions and to have an insight on the modulation of the photophysical properties upon complexation.

The title Co^IIIcomplex, bis[bis(2-hydroxy-3-methoxybenzaldehyde thiosemicarbazonato)cobalt(III)] dithionate–dimethylformamide–methanol (1/4/3), [Co(C₉H₁₀N₃O₂S)₂]₂(S₂O₆)·4C₃H₇NO·3CH₃OH, with monodeprotonated 2-hydroxy-3-methoxybenzaldehyde thiosemicarbazone as ligands crystallizes in the space groupP\overline{1}. The asymmetric unit consists of two mononuclear [CoL₂]⁺cations, one dithionate anion (S₂O₆)²⁻as counter-anion and seven solvate molecules (four dimethylmethanamide and three methanol). Each Co^IIIion has a moderately distorted octahedral S₂N₂O₂geometry. In the crystal, the components are linked by numerous N—H...O and O—H...O contacts.