Crystal structure and quantum chemical investigation of [Cd（NTO）₄Cd（H₂O）₆]·4H₂O

【Abstract】 Cd(NTO)4Cd(H2O)6]·4H2O was synthesized by mixing the aqueous solution of 3-nitro-1, 2,4-triazol-5-one (NTO) and cadmium carbonate. The single crystal structure was determined by a four-circle X-ray diffractometer. The crystal is monoclinic, space group C2/c with crystal parame-ters of a = 2.1229(3) nm, b = 0.6261(8) nm, c = 2.1165(3) nm, b = 90.602 (3)? V = 2.977(6) nm3, Z = 4, Dc = 2.055 g·cm-3, m = 15.45 cm-1 and F(000) = 1824. 2523 observable independent reflec-tions with F0>4s (F0) were used for the determination and refinement of the crystal structure. Lor- entz-polarization and absorption correction were applied. The final R is 0.0282 and wR = 0.0792. The analytical results show that the Cd2+ has two kinds of coordinate bonds in one crystal. One Cd2+ coordinates with 4 NTO anions and another coordinates with 6 water molecules to form a binucleate complex with a structure of tetrahedron and tetragonal bipyramid, respectively. By using SCF-PM3-MO method, the electron structure of cadmium complex of NTO has been calculated. The analysis of the calculated results shows that when [Cd(NTO)4Cd(H2O)6]·4H2O is heated, the crystallization waters will be dissociated first and the ligand waters second and NO2 group has pri- ority of leaving when NTO- is decomposed. Analysis of the energy level and composition of local- ized molecular orbitals indicates that both the two Cd2+ bond to the coordinating atom with 5s AO.更多还原