Synthesis and crystal structure of structurally different cadmium selenocyanate and thiocyanate coordination compounds containing 3‐chloropyridine as ligand

Abstract

Four compounds with the composition Cd(NCSe)2(3‐ClPy)4 (1), [Cd(NCSe)2(3‐ClPy)2] ⋅ 3‐ClPy (2), Cd(NCSe)2(3‐ClPy)2 (3) and Cd(NCSe)2(3‐ClPy) (4) with 3‐ClPy = 3‐chloropyridine were synthesized. In the structure of 1 discrete complexes are observed, whereas in 2 the Cd cations are linked by pairs of selenocyanato anions into chains and between the chains 3‐chloropyridine solvate molecules are embedded. In compound 3 each two Cd cations are linked by pairs of anionic ligands into dinuclear units, that are further connected into layers by μ‐1,3 single bridging selenocyanate anions. In compound 4, both, octahedrally and tetrahe‐ drally coordinated Cd cations are present, that are linked by μ‐1,3‐ bridging anionic ligands into a three‐.dimensional network.Thermoanalytical investigations prove that compound 1 loses the 3‐chloropyridine ligands stepwise upon heating and transforms into compound 4 via compound 3 as an intermediate. Further investigations show that the thiocyanate analogue Cd(NCS)2(3‐ClPy) 5 that is not reported in the literature can also be prepared. Since no single crystals were available, the structure was solved from PXRD data and refined using the Rietveld method, which revealed that this compound is an isomer of 4. In its crystal structure the Cd cations are linked by μ‐1,3(N,S) and μ‐1,3,3(N,S,S)‐bridging anionic ligands into chains that are further connected via Cd2S2 rings into double chains.