Bis(2-amino-3-methyl-pyridine-κN(1))dichloridomercury(II)

Isotypic one-dimensional coordination polymers: catena-poly[[di-chlorido-cadmium]-μ-5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ato-κ(2) N (5):N (6)] and catena-poly[[di-chlorido-mercury(II)]-μ-5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carboxyl-ato-κ(2) N (5):N (6)]

The isotypic title one-dimensional coordination polymers, [CdCl2(C18H14N4O4)] n , (I), and [HgCl2(C18H14N4O4)] n , (II), are, respectively, the cadmium(II) and mercury(II) complexes of the dimethyl ester of 5,6-bis-(pyridin-2-yl)pyrazine-2,3-di-carb-oxy-lic acid. In both compounds, the metal ions are located on a twofold rotation axis and a second such axis bis-ects the Car-Car bonds of the pyrazine ring. The metal ions are bridged by binding to the N atoms of the two pyridine rings and have an MN2Cl2 bisphenoidal coordination geometry. The metal-Npyrazine distances are much longer than the metal-Npyridine distances; the difference is 0.389 (2) Å for the Cd-N bonds but only 0.286 (5) Å for the Hg-N bond lengths. In the crystals of both compounds, the polymer chains are linked via pairs of C-H⋯Cl hydrogen bonds, forming corrugated slabs parallel to the ac plane.

(Acetato-κ(2)O,O')(acetato-κO)bis(2-amino-3-methyl-pyridine-κN(1))cobalt(II)

In the title compound, [Co(CH(3)COO)(2)(C(6)H(8)N(2))(2)], the Co(II) ion is five-coordinated by two pyridine N atoms from two 2-amino-3-methyl-pyridine ligands, two O atoms from one acetate ion and one O atom from another acetate ion in a distorted trigonal-bipyramidal geometry. The pyridine rings are nearly perpendicular to each other [dihedral angle = 84.49 (16)°]. The crystal packing is stabilized by intra-molecular and inter-molecular N-H⋯O hydrogen-bonding inter-actions.