Structural Diversity and Photoluminescent Properties of Zinc Benzotriazole-5-carboxylate Coordination Polymers

A series of zinc­(II) compounds, [Zn2(btca)2(im)2]·(DMA) (1; H2btca = benzotriazole-5-carboxylate acid, im = imidazole,
and DMA = N,N-dimethylacetamide),
[Zn­(btca)­(im)]·(DMF) (2; DMF = N,N-dimethylformamide), [Zn2(btca)2(tmdpy)]·2­(DMF)·5­(H2O) [3; tmdpy = 1,3-di­(4-pyridyl)­propane], and [H2N­(CH3)2]2[Zn3(btca)4]·(DMF)
(4), have been successfully synthesized via rational
control of experimental conditions. Single-crystal X-ray diffraction
analyses indicate that compounds 1 and 2 are isomers, and both of them exhibit two-dimensional structures
with the same uninodal 3-connected fes topology. Additionally,
the three-dimensional (3D) structure of 3 was obtained
by using tmdpy instead of an im ligand under synthesis conditions
similar to those of compound 2. Interestingly, compound 3 presents a pillared-layer structure with a (3,4)-connected
(4.82.103)­(4.82) topology. When 4,4′-bipyridine
was used to replace tmdpy, the assembly between Zn2+ ions
and H2btca ligands produced a chiral 3D framework of 4. Furthermore, compound 4 showed a new (3,4)-connected
topology with a vertex symbol of (4.6.84)2(4.6.8)­(4.82)­(6.82)2(6.85). A comparison
of all compounds suggested that the structural diversity of the compounds
could be tuned by altering the auxiliary ligand. In addition, the
photoluminescent properties of compounds 1–4 were
measured.