| Summary: | The isomers 4′-(4-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (<b>1</b>), 4′-(3-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (<b>2</b>), 4′-(4-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (<b>3</b>), and 4′-(3-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (<b>4</b>) have been prepared and characterized. The single crystal structures of <b>1</b> and <b>2</b> were determined. The 1D-polymers [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>1</b>)<sub>2</sub>]<i><sub>n</sub></i>·2<i>n</i>C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [Cu(hfacac)<sub>2</sub>(<b>2</b>)]<i><sub>n</sub></i>·2<i>n</i>C<sub>6</sub>H<sub>5</sub>Me, [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>3</b>)<sub>2</sub>]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub>, [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>3</b>)<sub>2</sub>]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>5</sub>Cl, and [Cu(hfacac)<sub>2</sub>(<b>4</b>)]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>5</sub>Cl have been formed by reactions of <b>1</b>, <b>2</b>, <b>3</b> and <b>4</b> with [Cu(hfacac)<sub>2</sub>]·H<sub>2</sub>O under conditions of crystal growth by layering and four of these coordination polymers have been formed on a preparative scale. [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>1</b>)<sub>2</sub>]<i><sub>n</sub></i>·2<i>n</i>C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> and [Cu(hfacac)<sub>2</sub>(<b>2</b>)]<i><sub>n</sub></i>·2<i>n</i>C<sub>6</sub>H<sub>5</sub>Me are zig-zag chains and the different substitution position of the CF<sub>3</sub> group in <b>1</b> and <b>2</b> 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 [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>3</b>)<sub>2</sub>]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> and [Cu(hfacac)<sub>2</sub>(<b>4</b>)]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>5</sub>Cl differs, leading to different structural motifs in the 1D-polymer backbones. In [Cu(hfacac)<sub>2</sub>(<b>4</b>)]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>5</sub>Cl, the peripheral 3-CF<sub>3</sub>C<sub>6</sub>H<sub>4</sub> unit is accommodated in a pocket between two {Cu(hfacac)<sub>2</sub>} units and engages in four C–H<sub>phenyl</sub>...F–C<sub>hfacac</sub> contacts which lock the phenylpyridine unit in a near planar conformation. In [Cu<sub>2</sub>(hfacac)<sub>4</sub>(<b>3</b>)<sub>2</sub>]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>4</sub>Cl<sub>2</sub> and [Cu(hfacac)<sub>2</sub>(<b>4</b>)]<i><sub>n</sub></i>·<i>n</i>C<sub>6</sub>H<sub>5</sub>Cl, 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 <b>1</b> and <b>2</b>. 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 <b>3</b> or <b>4</b>.
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