Syntheses and crystal structures of bis­(4-methyl­pyridine-κN)bis­(seleno­cyanato-κN)zinc(II) and catena-poly[[bis­(4-methyl­pyridine-κN)cadmium(II)]-di-μ-seleno­cyanato-κ(2) N:Se;κ(2) Se:N]

The reactions of Zn(NO(3))(2) (.)6H(2)O and Cd(NO(3))(2) (.)4H(2)O with KSeCN and 4-meth­yl­pyridine (C(6)H(7)N; 4-picoline) lead to the formation of crystals of bis­(4-methyl­pyridine-κN)bis­(seleno­cyanato-κN)zinc(II), [Cd(NCSe)(2)(C(6)H(7)N)(2)] (1), and catena-poly[[bis­(4-methyl­pyridine-κN)cadmium(II)]-di-μ-seleno­cyanato-κ(2) N:Se;κ(2) Se:N], [Cd(NCSe)(2)(C(6)H(7)N)(2)]( n ) (2), suitable for single-crystal X-ray diffraction. The asymmetric unit of compound 1 consists of one Zn cation that is located on a twofold rotation axis as well as one seleno­cyanate anion and one 4-methyl­pyridine ligand in general positions. The Zn cations are tetra­hedrally coordinated by two terminal N-bonding thio­cyanate anions and two 4-methyl­pyridine ligands, forming discrete complexes. The asymmetric unit of compound 2 consists of two crystallographically independent Cd cations, of which one is located on a twofold rotation axis and the second on a center of inversion, as well as two crystallographically independent seleno­cyanate anions and two crystallographically independent 4-methyl­pyridine ligands in general positions. The Cd cations are octa­hedrally coordinated by two N- and two S-bonding seleno­cyanate anions and two 4-methyl­pyridine ligands and are linked into chains by pairs of seleno­cyanate anions. Within the chains, the Cd cations show an alternating cis–cis–trans and all-trans coordination and therefore, the chains are corrugated. PXRD investigations prove that the Zn compound was obtained as a pure phase and that the Cd compound contains a very small amount of an additional and unknown phase. In the IR spectrum of 1, the CN stretching vibration of the seleno­cyanate anion is observed at 2072 cm(−1), whereas in the 2 it is shifted to 2094 cm(−1), in agreement with the crystal structures.