From discrete entity to three-dimensional architecture: Syntheses, crystal structures and optical properties of a series of transition metal complexes constructed from 4-carboxymethylbenzoic acid and 4,4′-bipyidine

Five new interesting transition metal coordination polymers [MnL2(bpy)2(H2O)2]n (1) (H2L = 4-carboxymethylbenzoic acid) (bpy = 4,4′-bipyidine), [CoL(bpy)(H2O)3 · H2O]n (2), [CdL(bpy)(H2O)3 · H2O]n (3), [Cu2L(bpy)2 · 3H2O]n (4) and [Zn2L2(bpy) · H2O]n (5) have been synthesized under solvothermal conditions and structurally characterized. This series of complexes has shown an intriguing variety of architectures, which firstly form zero- to two-dimensional frameworks by metal–ligand interactions, and secondly form three-dimensional supramolecular frameworks by intermolecular interactions such as hydrogen bonds. Compound 3 shows strong blue fluorescent emissions in the solid state upon photo-excitation at 359 nm at room temperature and may be an excellent candidate for blue-fluorescent materials. Compound 4 appears to be a good candidate for new hybrid inorganic–organic NLO materials.

Quadrangles and six-membered rings formed by hydrogen-bonds are essential to the three-dimensional supramolecular architecture.Figure optionsDownload as PowerPoint slide