Competition in Coordination Assemblies: 1D-Coordination Polymer or 2D-Nets Based on Co(NCS) and 4'-(4-methoxyphenyl)-3,2':6',3″-terpyridine.

The synthesis and characterization of 4'-(4-methoxyphenyl)-3,2':6',3″-terpyridine () (IUPAC PIN 2-(4-methoxyphenyl)-1,2:2,3-terpyridine) are described, and its coordination behaviour with cobalt(II) thiocyanate has been investigated. In a series of experiments, crystals were grown at room temperature by layering a MeOH solution of Co(NCS) over a CHCl solution of using 1:1, 1:2 or 2:1 molar ratios of metal salt-to-ligand. Crystals harvested within 2-3 weeks proved to be the 1D-coordination polymer [Co()(NCS)(MeOH)] and powder X-ray diffraction (PXRD) confirmed that the crystals selected for single-crystal X-ray diffraction were representative of the bulk samples. Longer crystallization times with a Co(NCS) to molar ratio of 1:1 yielded crystals of [Co()(NCS)(MeOH)] (1D-chain) and the pseudopolymorphs [{Co()(NCS)}·3MeOH] and [{Co()(NCS)}·2.2CHCl] ((4,4)-nets), each type of crystal originating from a different zone in the crystallization tube. PXRD for this last experiment confirmed that the dominant product in the bulk sample was the 1D-coordination polymer.