Bis[μ-2-(2,4-difluorophenyl)-1,3-bis(1H-1,2,4-triazol-1-yl)propan-2-olato]dicopper(II) bis(perchlorate)

The title complex, [Cu2(C13H11F2N6O)2](ClO4)2, which was hydrothermally synthesized, contains a binuclear copper cluster (2 symmetry) with a Cu2O2 rhombus [Cu—O = 1.927 (2) Å] formed by donation of two O atoms from two chelate rings. The tridentate function of each ligand is completed by two N atoms coordinated to the two CuII atoms [Cu—N = 1.933 (2) Å]. The separation distance of two CuII atoms in a cluster is 2.988 (1) Å. The dihedral angle between the six-membered chelate rings is 2.13 (9)°. The perchlorate counter-anion is disordered over two sites in a 0.58 (10):0.42 (10) ratio.

The title complex, [Cu 2 (C 13 H 11 F 2 N 6 O) 2 ](ClO 4 ) 2 , which was hydrothermally synthesized, contains a binuclear copper cluster (2 symmetry) with a Cu 2 O 2 rhombus [Cu-O = 1.927 (2) Å ] formed by donation of two O atoms from two chelate rings. The tridentate function of each ligand is completed by two N atoms coordinated to the two Cu II atoms [Cu-N = 1.933 (2) Å ]. The separation distance of two Cu II atoms in a cluster is 2.988 (1) Å . The dihedral angle between the six-membered chelate rings is 2.13 (9) . The perchlorate counter-anion is disordered over two sites in a 0.58 (10):0.42 (10) ratio.

Experimental
Crystal data [Cu 2 (C 13 H 11  Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. Comment 1,2,4-triazole and its derivatives, being used in pharmaceuticals and agricultural chemicals, have attracted ever-increasing attention in coordination chemistry (Haasnoot et al., 2000, Zhao et al., 2007. The coordination versatility of 1, 2, 4-triazole as a reliable bridging ligand, i.e. adopting diverse binding fashions upon metal complexation, will be responsible for structural diversity of the resulting coordination frameworks (Liu et al., 2003, Park et al., 2006, Yi et al., 2004, Garcia et al., 2005. Now, we present the synthesis and structure analysis of the title Hflu complex derived from bis-fluconazolato-di-copper diperchlorate. The distinct binding modes of the ligands (Scheme 1) and the coordination preferences of the metal ion are discussed. The title binuclear copper(II) compound, C 26 H 22 Cl 2 Cu 2 F 4 N 12 O 10 , reveals a centro-symmetric arrangement. The coordination of Cu1 is achieved by 1, 2, 4-triazole-N and flu-O ligands (Fig. 1); two oxygen atoms of fluconazole molecule form rhombus with two copper atoms with Cu-O1 bond of 1.927 (2) Å, forming a Z-style structure. The perchlorate ion is not coordinated to Cu II atom. It take a part in formation of an ornament of 'palace lantern-style'geometry ( Fig. 2). The perchlorate anions adopt two crystallographic orientations in the crystal lattice with occupancy factors of 0.576 and 0.424.
The dihedral angle between two 1, 2, 4-triazole groups in the same fluconazole ligand is 68.25 (9) ° and the dihedral angle between two ipso-lateral 1, 2, 4-triazole groups in the same molecular binuclear copper cluster is 68.25 (9) ° (Fig. 1). In order to achieve the optimum coordination, fluconazole molecules were adjusted into epsilon-type arrangement.

Refinement
H atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 Å and U iso (H) = 1.2U eq (C) for aromatic H atoms, C-H = 0.97 Å and U iso (H) = 1.2U eq (C) for methylene H atoms. The thermalfactors being set 1.5 times of their carrier atoms.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.