engleski

Monoaquabis(2, 2'-bipyridine)(saccharinato-N)zinc saccharinate. Crystal structure determination and spectra –structure correlations

In the course of our systematic investigation of structures of 2, 2'-bipyridine saccharinato complexes with various metals, the zinc complex was synthesized and studied by X-ray diffraction and FT IR spectroscopy. The crystal structure determination of the title compound revealed the formula [Zn(H_2O)(bpy)_2(sac)](sac). The compound crystallizes in the monoclinic system, space group P2_1/n, a = 7.7448(13), b = 31.524(6), c = 13.2793(20) A, b = 93.504(13)^o, R = 0.041, wR = 0.060. The structure is built up of [Zn(H_2O)(bpy)_2(sac)]^+ cations and [sac]^- anions. The central metal atom is octahedrally coordinated by four nitrogen atoms belonging to two 2, 2'-bipyridine molecules, one nitrogen atom from the coordinated saccharinate ligand and the water oxygen atom. The coordinated saccharinato ligand is hydrogen bonded (via its carbonyl oxygen) to the water molecule. The second saccharinate anion does not participate in the metal coordination sphere but is involved in hydrogen bonding with the water molecule through its nitrogen atom. So, the crystal structure packing is achieved through intra- and interionic contacts of O_W^.^.^.O_CO, O_W^.^.^.N_sac as well as C-H^.^.^.^.O type. The FT IR spectra of the title compound are studied as well. Attention is paid to the stretching H_2O, CO and SO_2 regions. The geometry of the water molecule is discussed regarding the spectroscopic and structural evidence. The appearance of the CO and SO_2 stretching regions is correlated with the number of non-equivalent CO and SO_2 groups in the structure. Spectral and structural characteristics of the title compound are compared with those of the corresponding complexes of Co, Ni and Cu.

Metal saccharinates; zinc(II) complexes; X-ray diffraction

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