Synthesis, structure and characterization of two Cd(II) coordination polymers with helical structures

Abstract

Two coordination polymers, [Cd₂Cl₂(1,3-BDC)(TTBT)(H₂O)] (1) and [CdCl(1,4-HBDC)(TTBT)] (2) (1,3-BDC = 1,3-benzenedicarboxylate, 1,4-BDC = 1,4-benzenedicarboxylate, and TTBT = 10,11,12,13-tetrahydro-4,5,9,14-tetraaza-benzo[b]triphenylene), have been prepared under hydrothermal conditions and characterized by elemental analyses, IR spectra, thermal gravimetry (TG), fluorescence emission and single crystal X-ray diffraction analyses. The crystal structures were determined by X-ray diffraction and refined by full-matrix least-squares methods to R = 0.0621 and wR = 0.1543 using 4937 reflections with I > 2σ(I) for 1; and R = 0.0525 and wR = 0.1427 using 3386 reflections with I > 2σ(I) for 2. Compound 1 possesses a chiral chain structure. Adjacent chiral chains are further linked through π–π interactions between TTBT ligands to give a three-dimensional supramolecular architecture. Compound 2 displays a helical chain structure, with neighboring chains stacked by π–π interactions, generating an unusual three-dimensional supramolecular structure.

Keywords:

• Helical coordination polymers
• Crystal structure
• IR spectrum
• Photoluminescence
• TG

Acknowledgements

The authors thank the Natural Science Foundation of Jilin Province (No. 20060516), the Doctoral Foundation of Jilin Normal University (No. 2006006), the Science and Technology Institute Foundation of Siping City (No. 2005016) and the Subject and Base Construction Foundation of Jilin Normal University (No. 2006041).