Supramolecular architectures constructed with the skeletons of zinc(II) 2,2′-bipyridine and barbiturate anion: Synthesis and characterization

The barbiturate 1,5-dihydro-5-[5-pyrimidine-2,4(1H,3H)-dionyl]-2H-chromeno[2,3-d] pyrimidine-2,4(3H)-dione) (LH4) 1 forms a complex with Zn(bpy)(NO3)2·2H2O (bpy = 2,2′-bipyridine) of composition [Zn(bpy)2(H2O)2]2+·(LH3)2·7H2O (2). In this structure, the ligand exists as anion (LH3-) as revealed by its single crystal X- ray crystallographic study. Packing studies of 2 provide three dimensional helical chains as secondary structure. However, its PXRD pattern shows that 2 does not retain its structure upon dehydration. Recrystallization of 2 from DMSO results in complex 3 with the composition [Zn(bpy)2(H2O)2]2+·(LH3-)2·DMSO·9H2O assigned on the basis of its elemental analysis and its X-ray crystallography. In order to understand the role of the 2,2′-bipyridine ring in the construction of supramolecular architecture, the reaction of zinc(II) nitrate salt with 1 is carried out to provide complex 4 of composition [Zn(LH3)2(H2O)4]·4H2O characterized by its single crystal X-ray diffraction study. Thermal, emission and photoluminescence properties of the complexes are also studied.

A barbiturate derivative complexed with Zn(bpy)(NO3)2·2H2O and Zn(NO3)2·H2O provides fluorescent supramolecular architectures which are characterized by their single crystal X-ray crystallographic studies.Figure optionsDownload as PowerPoint slide