Parallel stacking interactions in square-planar transition-metal complexes containing fused chelate and C6-aromatic rings.

Stacking interactions in the crystal structures of square-planar transition metal complexes from the Cambridge Structural Database with five- and six-membered chelate rings fused with C(6-arom) rings (arom = aromatic) were analyzed. The distribution of distances between the closest C(6-arom)-C(6-arom) and C(6-arom)-chelate contacts shows that in a large fraction of the intermolecular interactions the C(6-arom) ring of one molecule is closer to the chelate than to the C(6-arom) ring of the other molecule. These results indicate a possible preference of the C(6-arom) ring to form stacking contacts with the chelate rings. The preference is ubiquitous and does not depend on the metal type.

Tris(3,5-dimethyl-1H-pyrazole-1-thiocarboxamidato-kappa(2)N(2),N)cobalt(III).

In the crystal structure of the title complex, [Co(C(6)H(8)N(3)S)(3)], the Co(III) atom is octahedrally coordinated by three monodeprotonated bidentate 3,5-dimethyl-1H-pyrazole-1-thiocarboxamide ligands with two thiocarboxamide N atoms in axial positions. The asymmetric unit contains two molecules (A and B) and these molecules are arranged in chains in an alternating fashion connected by N-H...S interactions.

Transition metal complexes with thiosemicarbazide-based ligands. XLIII. Chlorobis(3-methylisoemicarbazide-kappa(2)N(1),N(4))zinc(II) chloride.

In the title compound, [ZnCl(C(2)H(7)N(3)S)(2)]Cl, the Zn(II) ion is five-coordinated in a distorted trigonal-bipyramidal arrangement, with the hydrazine N atoms located in the apical positions. The structure is stabilized by N[bond]H...Cl hydrogen bonds, which involve both the Cl atoms and all the hydrogen donors, except for one of the two thioamide N atoms. A comparison of the geometry of thiosemicarbazide and S-methylisothiosemicarbazide complexes with Zn(II), Cu(II) and Ni(II) shows the pronounced influence of the hydrogen-bond network on the coordination geometry of Zn(II) compounds.