Synthesis, crystal structure and thermal properties of -poly[[bis-(4-methyl-pyridine)-nickel(II)]-di-μ-thio-cyanato], which shows an alternating all- and --coordination of the NiSN N octa-hedra (p = 4-methyl-pyridine, t = thio-cyanate).

The title compound, [Ni(NCS)(CHN)] , was prepared by the reaction of Ni(NCS) with 4-methyl-pyridine in water. Its asymmetric unit consists of two crystallographically independent Ni cations, of which one is located on a twofold rotational axis whereas the second occupies a center of inversion, two independent thio-cyanate anions and two independent 4-methyl-pyridine co-ligands in general positions. Each Ni cation is octa-hedrally coordinated by two 4-methyl-pyridine coligands as well as two N- and two S-bonded thio-cyanate anions. One of the cations shows an all-, the other a -- configuration. The metal centers are linked by pairs of μ-1,3-bridging thio-cyanate anions into [101] chains. X-ray powder diffraction shows that a pure crystalline phase has been obtained and thermogravimetry coupled to differential thermoanalysis reveals that the title compound loses half of the 4-methyl-pyridine coligands and transforms into Ni(NCS)(CHN). Nearly pure samples of this compound can be obtained by thermal annealing and a Rietveld refinement demonstrated that it is isotypic to its recently reported Cd analog [Neumann , (2020 ▸). , 184-194] In its crystal structure, the metal cations are linked by one μ-1,3(,)- and one μ-1,3,3(,,)-bridging thio-cyanate anion into single chains that condense the μ-1,3,3(,,)-bridging anionic ligands into double chains.