Monoaquabis(2,2′-bipyridine)saccharinatozinc(II) saccharinate. 1. Structural study by single crystal X-ray diffraction, FTIR, and DS calorimetry

Structural characteristics of monoaquabis(2,2′-bipyridine)saccharinatozinc(II) saccharinate (I) were studied by X-ray diffraction, Fourier transform IR spectroscopy, and differential scanning calorimetry (DSC). The X-ray study led to the formula [Zn(H₂O)(bpy)₂(sac)](sac), where bpy = 2,2′-bipyridine, and sac = saccharinato ion/ligand. The structure is built from [Zn(H₂O)(bpy)₂(sac)]⁺ cations and [sac]^- anions. There are two crystallographically independent saccharinate anions and 2,2′-bipyridine molecules. In the crystal structure, the packing is dominated by the net of hydrogen bonds between the saccharinato ligand ions and the water molecules and within these ions and molecules, and also by C-H⋯O contacts. IR spectra in characteristic regions of H₂O, CO, and SO₂ stretching vibrations have been studied. The geometry of the water molecules is discussed with allowance for the spectroscopic and structural data. The appearance of the CO and SO₂ stretching vibrations in the spectrum of the compound correlates with the number of nonequivalent carbonyl and sulfonyl groups in the structure. Thermal DSC analysis was used to determine the decomposition rate and the stability of the complex.