Dinuclear zinc(II) acetate complexes derived from N,N',S-tridentate Schiff bases: synthesis, structural study and Hirshfeld surface analysis.

Three dinuclear zinc(II) acetate complexes of the general formula [Zn{L}(AcO)], namely, di-μ-acetato-κO:O'-bis[({2-[(pyridin-2-ylmethylidene)amino]phenyl}sulfanido-κN,N',S)zinc(II)], [Zn(CHNS)(CHO)] (n = 1), 4, μ-acetato-1:2κO:O'-acetato-2κO-[μ-(2-{[1-(pyridin-2-yl)ethylidene]amino}phenyl)sulfanido-1κS:2κN,N',S][(2-{[1-(pyridin-2-yl)ethylidene]amino}phenyl)sulfanido-1κN,N',S]dizinc(II), [Zn(CHNS)(CHO)] (n = 2), 5, and μ-acetato-1:2κO:O'-acetato-2κO-[μ-(2-{[phenyl(pyridin-2-yl)methylidene]amino}phenyl)sulfanido-1κS:2κN,N',S][(2-{[phenyl(pyridin-2-yl)methylidene]amino}phenyl)sulfanido-1κN,N',S]dizinc(II)-bis(2-aminophenyl) disulfide (2/1), [Zn(CHNS)(CHO)]·0.5CHNS (n = 3), 6·0.5(2-APS), were obtained from the reaction of 2-R-(pyridin-2-yl)benzothiazoline precursors (R = H, 1; R = Me, 2; R = Ph, 3) with zinc acetate dihydrate in a 1:1 ratio. All the complexes crystallized as dinuclear species and complex 6 cocrystallized with one molecule of bis(2-aminophenyl) disulfide (2-APS). The anionic Schiff base ligands {L} displayed a κN,κS-tridentate coordination mode with the formation of two five-membered chelate rings. In 4, 5 and 6·0.5(2-APS), both Zn ions are pentacoordinated and the coordination sphere of 4 was different with respect to those in 5 and 6·0.5(2-APS). For 4, the X-ray diffraction study showed a dinuclear complex containing two bridging acetate ligands linked to both Zn ions. For 5 and 6·0.5(2-APS), the dinuclear complexes displayed one bridging acetate ligand linked to both Zn ions, where the first Zn ion includes a dative bond with one S atom from an adjacent anionic Schiff base {L}, while the second Zn ion is coordinated to one terminal acetate ligand. In each dinuclear complex, the geometry is the same for both Zn metal centres. The local geometry of the Zn cation in 4 is halfway between trigonal bipyramidal and square pyramidal local geometries; in 5 and 6, the local geometries are described as distorted square pyramidal. Hirshfeld surface analysis of 5 and 6 showed the predominance of H...H interactions, as well as the contribution of C-H...C, C-H...O and C-H...S noncovalent interactions to the cohesion of the crystalline network of the Zn complexes.