[Bis(quinolin-2-ylcarbonyl)amido-κ3 N,N′,N′′]bromido(N,N-dimethylformamide-κO)copper(II)

In the mononuclear title complex, [CuBr(C20H12N3O2)(C3H7NO)], synthesized from the quinoline-derived reduced Schiff base 4-(quinolin-2-ylmethyl)aminophenol, the coordination geometry around Cu2+ is distorted square-pyramidal, comprising a bromide anion at the apex [Cu—Br = 2.4671 (5) Å]. The base of the pyramid is built up from one dimethylformamide O-atom donor [Cu—O = 2.078 (2) Å] and three N-atom donors from the monoanionic, tridentate bis(quinolin-2-ylcarbonyl)diimide ligand [Cu—Ndiimide = 1.941 (3) Å, and Cu—Nquinolyl = 2.060 (3) and 2.049 (3) Å]. An intramolecular C—H⋯O occurs. In the crystal, weak methyl and aromatic C—H⋯Br and formyl C—H⋯Ocarbonyl hydrogen-bonding interactions generate an overall layered structure lying parallel to (001).


Comment
The new ligand bis(2-quinolylcarbonyl)diimide monoanion (BQCD), formed from the quinoliny derived reduced Schiff base 4-(quinolin-2-ylmethyl)aminophenol (R-QMAP), is an important compound widely used in biological applications such as an HIV-1 protease inhibitor and in coordination chemistry (Castro et al., 1990;Castro et al., 1991;Lebon et al., 1998;Castro et al., 1999;Calatayud et al., 2000;Vangdal et al., 2002;Carlucci et al., 2011). In the synthesis of a compound from the reaction of CuBr with BQCD in ethanol with subsequent recrystallization from dimethylformamide generated the title Cu II complex [Cu(C 20 H 12 N 3 O 2 )(C 3 H 7 NO)Br] which contains the monoanionic bis(2-quinolylcarbonyl) diimide ligand (BQCD), one bromido anion and an O-bonded dimethylformamide solvent molecule. The ligand, a bis(2quinolylcarbonyl)diimide monoanion (BQCD) was formed from a reduced Schiff base 4-(quinolin-2-ylmethyl)aminophenol ( i R-QMAP), by the breaking of the aminophenol and subsequent oxidation of the -CH 2 -group to a carbonyl group in the presence of dioxygen and copper(I) bromide. This oxidation of the -CH 2 -group to a carbonyl group in the presence of dioxygen and metal salts has previously been reported (Sahu et al., 2010).
In the title mononuclear complex (Fig. 1), the Cu II center is penta-coordinated with a distorted square pyramidal In the crystal, a weak intermolecular methyl C23-H···Br1 i interaction (Table 1) generates a chain structure extending along the c axial direction (Fig. 2), and is further extended into a two-dimensional sheet structure lying parallel to (001) through aromatic C15-H···Br ii and formyl C22-H···O3 iii hydrogen bonds (Fig. 3). Also present in the structure is an intramolecular aromatic C20-H···O1 formyl hydrogen bond.

Experimental
A mixture of reduced Schiff base 4-(quinolin-2-ylmethyl)aminophenol ( i R-QMAP) (0.10 g, 0.40 mmol), copper(I) bromide (0.060 g, 0.40 mmol), ethanol (5 mL) were stirred vigorously for 30 min, the precipitate was filtered off and dissolved in dimethylformamide and kept for crystallization. Crystals suitable for X-ray analysis were obtained within a week by slow evaporation of the DMF solvent.

Refinement
The H-atoms of the methyl group involved in the chain formation (C23) were located in a difference-Fourier and were fully refined. All other H-atoms were positioned geometrically and refined using a riding model with C-H = 0.93-0.96 Å and U iso (H) = 1.2U eq (aromatic C) or 1.5U eq (methyl C).

Figure 1
The molecular conformation and atom-numbering scheme for the title complex with non-H atoms drawn as 30% probability displacement ellipsoids.

Figure 2
The one-dimensional chain structure in the title complex extending along c, with weak C-H···Br hydrogen bonds shown as dashed lines.  The two-dimensional structure viewed along the c-axial direction.

[Bis(quinolin-2-ylcarbonyl)amido-κ 3 N,N′,N′′]bromido(N,N-dimethylformamide-κO)copper(II)
Crystal data [CuBr(C 20  Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.