Syntheses and crystal structures of the ethanol, acetonitrile and diethyl ether Werner clathrates bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II).

The reaction of nickel(II)thio-cyanate with 3-methyl-pyridine (3-picoline; C(6)H(7)N) in different solvents leads to the formation of crystals of bis-(iso-thio-cyanato-κN)tetra-kis-(3-methyl-pyridine-κN)nickel(II) as the ethanol disolvate, [Ni(NCS)(2)(C(6)H(7)N)(4)]·2C(2)H(5)OH (1), the acetonitrile disolvate, [Ni(NCS)(2)(C(6)H(7)N)(4)]·2CH(3)CN (2), and the diethyl ether monosolvate, [Ni(NCS)(2)(C(6)H(7)N)(4)]·C(4)H(10)O (3). The crystal structures of these compounds consist of Ni(II) cations coordinated by two N-bonded thio-cyanate anions and four 3-methyl-pyridine ligands to generate NiN(6) octa-hedra with the thio-cyanate groups in a trans orientation. In compounds 1 and 2 these complexes are located on centers of inversion, whereas in compound 3, they occupy general positions. In the crystal structures, the complexes are packed in such a way that cavities are formed in which the solvent mol-ecules are located. Compounds 1 and 2 are isotypic, which is not the case for compound 3. In compounds 1 and 2 the solvate mol-ecules are disordered, whereas they are fully ordered in compound 3. Disorder is also observed for one of the 3-methyl-pyridine ligands in compound 2. Powder X-ray diffraction and IR measurements show that at room temperature all compounds decompose almost immediately into the same phase, as a result of the loss of the solvent mol-ecules.