Crystal Structure of the [Cu(dafone)2Cl2] 2H2O Complex (dafone = 4,5-diazafluoren-9-one)

Abstract

The reaction exocyclic keto function in dafone offers distinct advantages for further derivatization to yield multinuclear metal complexes having interesting catalytic and biological properties. 1 A large number of transition-metal complexes with a dafone ligand have been synthesized and structurally characterized. 2,3 In these complexes, it was found that the anions could coordinate directly with the center metal ions when the dafones form complexes with metal chlorides, bromides, iodides and thiocyanates, but when the dafones form complexes with metal nitrates, perchlorates, and so on, the water molecules, rather than counteranions, coordinate to the centre metal ions directly. Herein, we wish to report crystal structure of the [Cu(dafone)2Cl2]·2H2O complex, although that of the Cu(dafone)2Cl2 complex had been reported previously. 4 The ligand dafone was prepared according to procedures in the literature. 5 A mixture of CuCl2·2H2O (0.170 g, 1 mmol) and dafone (0.364 g, 2 mmol) was dissolved in about 20 ml of 1 M HCl solution and then refluxed for 2 h. The undissolved materials were removed by filtration. The filtrate was set aside to crystallize, providing green block single crystals after two weeks.Details of the X-ray structure determination of the title complex are given in Tables 1 -3. Absorption corrections were made using Semi-empirical from equivalents. The structure was solved by direct methods and refined by full-matrix leastsquares on F 2 using the SHELXTL software package. All nonhydrogen atoms were refined anisotropically. Hydrogen atoms bonded to the ligand were placed geometrically and allowed to subsequently ride with an isotropic displacement parameter fixed at 1.2-times Ueq of the atoms to which they were attached.Hydrogen atoms of the solvents were first located from difference Fourier maps and then placed at geometrically calculated positions. A chemical diagram is shown in Fig. 1 and the structure is shown in Fig. 2.The title complex crystallizes in monoclinic space group C2/c; the Cu(II) ion lies on a crystallographic inversion center. As shown in Fig. 2, each Cu(II) ion is six coordinated with a coordination geometry of a distorted octahedron. The basal plane is built up of two nitrogen atoms and two chloride ions arranged in a trans fashion. The apical positions are occupied by two weakly bonding nitrogen atoms, thus completing a distorted (2+2+2) octahedron. Compared with that of the Cu(dafone)2Cl2 complex reported previously, 4 they have the same coordination mode. The differences between them are that the title complex, [Cu(dafone)

Synthesis, Structure, Fluorescence, and Theoretical Studies of CuCl(2,2′-Bipyridine)2·3.5H2O

“…As shown in Table 2, the bond lengths of Cu-N are in the range of 1.945(6)-2.049(7) A with an average value of 2.013(7) A , comparable with those reported previously. [6][7][8][9] The bond length of Cu-Cl is 2.375(2) A , which is normal and comparable with the cases found in the literature. [10][11][12] Table 2.…”