Adapting (4,4) Networks through Substituent Effects and Conformationally Flexible 3,2':6',3"-Terpyridines.

Coordination networks formed between Co(NCS) and 4'-substituted-[1,1'-biphenyl]-4-yl-3,2':6',3"-terpyridines in which the 4'-group is Me (), H (), F (), Cl () or Br () are reported. [Co()(NCS)]·4.5CHCl, [Co()(NCS)]·4.3CHCl, [Co()(NCS)]·4CHCl, [Co()(NCS)], and [Co()(NCS)]·CHCl are 2D-networks directed by 4-connecting cobalt nodes. Changes in the conformation of the 3,2':6',3"-tpy unit coupled with the different peripheral substituents lead to three structure types. In [Co()(NCS)]·4.5CHCl, [Co()(NCS)]·4.3CHCl, [Co()(NCS)]·4CHCl, cone-like arrangements of [1,1'-biphenyl]-4-yl units pack through pyridine…arene π-stacking, whereas Cl…π interactions are dominant in the packing in [Co()(NCS)] The introduction of the Br substituent in ligand switches off both face-to-face π-stacking and halogen…π-interactions, and the packing interactions are more subtly controlled. Assemblies with organic linkers - are structurally similar and the lattice accommodates CHCl molecules in distinct cavities; thermogravimetric analysis confirmed that half the solvent in [Co()(NCS)]·4CHCl can be reversibly removed.