The isomers 4′-(4-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (1), 4′-(3-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (2), 4′-(4-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (3), and 4′-(3-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (4) have been prepared and characterized. The single crystal structures of 1 and 2 were determined. The 1D-polymers [Cu₂(hfacac)₄(1)₂]_n·2nC₆H₄Cl₂ (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [Cu(hfacac)₂(2)]_n·2nC₆H₅Me, [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂, [Cu₂(hfacac)₄(3)₂]_n·nC₆H₅Cl, and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl have been formed by reactions of 1, 2, 3 and 4 with [Cu(hfacac)₂]·H₂O under conditions of crystal growth by layering and four of these coordination polymers have been formed on a preparative scale. [Cu₂(hfacac)₄(1)₂]_n·2nC₆H₄Cl₂ and [Cu(hfacac)₂(2)]_n·2nC₆H₅Me are zig-zag chains and the different substitution position of the CF₃ group in 1 and 2 does not affect this motif. Packing of the polymer chains is governed mainly by C–F...F–C contacts, and there are no inter-polymer π-stacking interactions. The conformation of the 3,2′:6′,3″-tpy unit in [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂ and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl differs, leading to different structural motifs in the 1D-polymer backbones. In [Cu(hfacac)₂(4)]_n·nC₆H₅Cl, the peripheral 3-CF₃C₆H₄ unit is accommodated in a pocket between two {Cu(hfacac)₂} units and engages in four C–H_phenyl...F–C_hfacac contacts which lock the phenylpyridine unit in a near planar conformation. In [Cu₂(hfacac)₄(3)₂]_n·nC₆H₄Cl₂ and [Cu(hfacac)₂(4)]_n·nC₆H₅Cl, π-stacking interactions between 4′-trifluoromethylphenyl-3,2′:6′,3″-tpy domains are key packing interactions, and this contrasts with the packing of polymers incorporating 1 and 2. We use powder X-ray diffraction to demonstrate that the assemblies of the coordination polymers are reproducible, and that a switch from a 4,2′:6′,4″- to 3,2′:6′,3″-tpy metal-binding unit is accompanied by a change from dominant C–F...F–C and C–F...H–C contacts to π-stacking of arene domains between ligands 3 or 4.

The consistent assembly of a (6⁵.8) cds net is observed in reactions of cobalt(II) thiocyanate with 1,4-bis(n-alkyloxy)-2,5-bis(3,2′:6′,3″-terpyridin-4′-yl)benzene ligands in which the n-alkyloxy substituents are n-propyl (ligand 3), n-butyl (4), n-pentyl (5), n-hexyl (6), n-heptyl (7), and n-octyl (8). Crystals were grown by layering a methanol solution of Co(NCS)₂ over a 1,2-dichlorobenzene solution of each ligand. The choice of crystallization solvents is critical in directing the assembly of the cds net. Single-crystal structures of [Co(NCS)₂(3)]_n^.3.5nC₆H₄Cl₂, [Co(NCS)₂(4)]_n^.5.5nC₆H₄Cl₂, [Co(NCS)₂(5)]_n^.4nC₆H₄Cl₂, [Co(NCS)₂(6)]_n^.3.8nC₆H₄Cl₂, [Co(NCS)₂(7)]_n^.3.1nC₆H₄Cl₂, and [Co(NCS)₂(8)]_n^.1.6nC₆H₄Cl₂^.2nMeOH (C₆H₄Cl₂ = 1,2-dichlorobenzene) are presented and compared. The n-alkyloxy chains exhibit close to extended conformations and are accommodated in cavities in the lattice without perturbation of the coordination framework.