PECULIARITIES OF THE CRYSTAL-STRUCTURE AND PACKING OF THE HOST AND GUEST MOLECULES IN THE [M(4-MEPY)4(NCS)2].0.67(4-MEPY).0.33 H2O CLATHRATES (M = CU(II), MN(II) 4-MEPY = 4-METHYLPYRIDINE)

The crystal structures of the two clathrates with the composition [M(4-MePy)4(NCS)2].0.67(4-MePy).0.33 H2O (M = Cu(II), Mn(II); 4-MePy = 4-methylpyridine) have been determined. These compounds are trigonal, with the [M(4-MePy)4(NCS)2] host molecules being centrosymmetric. The parameters of the unit cells are a = 27.365(7) and 27.738(6), c = 11.303(9) and 11.250(8) angstrom, V = 7325(2) and 7493(2) angstrom3, space group R3BAR, R = 0.053 and 0.109 for M = Cu(II) and Mn(II). respectively. For Z = 9 d(calcd) is equal to 1.271 and 1.225 g/cm3, and d(measd) is equal to 1.252(2) and 1.213(2) g/cm3 for the Cu and Mn clathrates, respectively. The coordination environment of the metal atoms in these compounds is an irregular octahedron, while in the Mn compound these distortions are rather small (Mn-N(MePy) 2.30, 2.34 angstrom, Mn-N(NCS) 2.18 angstrom, and Cu-N(MePy) 2.06 angstrom, Cu-N(NCS) 1.98 angstrom and Cu-N(MePy) 2.50 angstrom). The molecular packing in the structures is such that the channels of variable diameter are formed along the short cell dimension (the maximum diameter is is-approximately-equal-to 10 angstrom, the minimum being is-approximately-equal-to 6 angstrom) where the guest 4-MePy and H2O molecules are placed.