Zinc(ΙΙ) complexes with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate and different N-donors: syntheses, crystal structures, and emission properties

Abstract

Two new Zn^II complexes, {[Zn(L)(phen)(H₂O)] · H₂O}_∞ (1) and {[Zn(L)(4bpy)(H₂O)] · H₂O}_∞ (2) (L = 5,6-dihydro-1,4-dithiin-2,3-dicarboxylate, phen = 1,10-phenanthroline, and 4bpy = 4,4′-bipyridine), have been prepared by in situ reaction of Zn(ClO₄)₂ · 6H₂O with 5,6-dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate in the presence of lithium hydroxide, together with incorporating chelating phen or bridging 4bpy as co-ligands. Their structures were determined by single-crystal X-ray diffraction. Complex 1 takes a 1-D helical structure that is further assembled into a 2-D network by O–H ··· O, C–H ··· O hydrogen bonds, and weak S ··· S interactions, and then an overall 3-D supramolecular framework was formed by π ··· π stacking interactions. Complex 2 possesses a 2-D (4,4)-layered structure. The structural difference between 1 and 2 can be attributed to the different N-donor auxiliary co-ligands. Both 1 and 2 are photoluminescent materials whose emission properties are closely related to their intrinsic structure.

Keywords:

• Zinc(ΙΙ) complexes
• 5,6-Dihydro-1,4-dithiin-2,3-dicarboxylic anhydrate
• Crystal structures
• Luminescence

Acknowledgments

This work was supported by the National Natural Science Fund of China (Grant Nos 20801049 and 21071129), Henan Outstanding Youth Science Fund (No. 114100510017), and Natural Science Fund of the Education Department of Henan Province (No. 2011A150032).