Hexa-μ2-chlorido-μ4-oxido-tetrakis[(morpholine-κN)copper(II)] methanol disolvate

In the title solvate, [Cu4(μ2-Cl)6(μ4-O)(C4H9NO)4]·2CH3OH, each Cu2+ ion in the tetranuclear complex has a trigonal–bipyramidal coordination arising from three bridging chloride ions in equatorial positions and the central μ4-O2− ion and morpholine N atom in axial positions. The morpholine rings adopt chair conformations, with the N—Cu bonds in equatorial orientations. In the crystal, the components are linked by N—H⋯O and O—H⋯O and O—H⋯Cl hydrogen bonds, which generate a three-dimensional network. One methanol molecule is disordered over two sets of sites in a 0.642 (9):0.358 (9) ratio.

In the title solvate, [Cu 4 ( 2 -Cl) 6 ( 4 -O)(C 4 H 9 NO) 4 ]Á2CH 3 OH, each Cu 2+ ion in the tetranuclear complex has a trigonalbipyramidal coordination arising from three bridging chloride ions in equatorial positions and the central 4 -O 2À ion and morpholine N atom in axial positions. The morpholine rings adopt chair conformations, with the N-Cu bonds in equatorial orientations. In the crystal, the components are linked by N-HÁ Á ÁO and O-HÁ Á ÁO and O-HÁ Á ÁCl hydrogen bonds, which generate a three-dimensional network. One methanol molecule is disordered over two sets of sites in a 0.642 (9):0.358 (9) ratio.

Introduction
Polynuclear copper (II) complexes have been known for a long time and studied comprehensively (Bertrand et al., 1966;Pavlenko et al., 1993;Linert et al., 1993;Bowmaker et al., 2011). On the one hand they play significant role in the redox processes of biological systems (Erecinska et al., 1978) and exhibit an interesting pattern of magnetic and electronic interactions in the copper-oxygen cluster (Willett et al., 1991, Chivers et al., 2005, Li et al., 2011. On the other hand in the case of systems involving copper (II) salts and nitrogen bases the presence of air and moisture leads to formation of occasionally crystallizing copper (II) substances. (Weinberger et al., 1998, Roy et al., 2010. They are interesting in their own right, providing some important model compounds, subjected to subsequent 'rational′ synthesis (Bowmaker et al., 2011). Herein we describe the structure of such kind complex of the general composition [Cu 4 OCl 6 (C 4 H 9 NO) 4 ]·2CH 3 OH and compare with the similar acetone containing coordination compound, that was published by Weinberger et al., 1998.

Experimental
All chemicals were commercial products of reagent grade and were used without further purification. Solvents were used as supplied or were distilled using standard methods.
Elemental analysis (C, H, N) was carried out on an Elementar Vario Micro Cube elemental analyzer. Cu ion was determined using of Perkin-Elmer AAS Analyst 400. IR spectra were recorded using KBr pellets on a Perkin-Elmer Spectrum BX FTIR spectrophotometer in the range of 4000 to 400 cm -1 .
Initial ligand (HL= OC 4 H 8 NC(O)NHP(O)(C 4 H 8 NO) 2 ) (Scheme, Fig.3) for the synthesis of (I) was prepared according to the method of (Gubina et al., 1999). The sodium salt NaL was obtained from a methanol solution by interaction of HL with sodium methoxide in equimolar ratio. An expected complex with the composition [Cu(L) 2 ], has to be obtained by an exchange reaction according Scheme (a). Solutions of NaL (2mmol) in methanol (10ml) with a solution of hydrated copper(II) chloride (1mmol) in methanol (15ml) were mixed. The resulted light green solution turned brown after a while. Most likely the phosphorylated carbamide ligand was destruct under catalytic influence of a copper ion and moisture of air. The released morpholine molecules formed the new copper (II) coordination compound of the general formula [Cu 4 OCl 6 (C 4 H 9 NO) 4 ]·2CH 3 OH (Scheme b). The product was filtered out, washed with cold methanol and dried in desiccator under CaCl 2 (yield 67%). The compound was recrystallised from methanol yielding brown blocks of an methanol solvate [Cu 4 OCl 6 (C 4 H 9 NO) 4 ]·2CH 3 OH. The crystals slowly lost the solvent at room temperature. IR spectra of supporting information sup-2 Acta Cryst. (2014). E70, m276-m277 obtained compound (I) show the absence of C=O and P=O bands. IR (KBr): δ s (CH 2 ) 1400 vs, δ as (CH 2 ) 1245s, ν(CN) 1040 vs, δ s (CNC) 600 vs, ν(Cu 4 O) 580s, ν(CuN) 443m, cm -1 .

Synthesis and crystallization
Slow crystallization from methanol.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 1. All H atoms of methyl methanol molecules and methylene groups of morpholine rings were calculated geometrically and subsequently treated as riding model, with C-H = 0.98 (methyl) C-H = 0.98 (methylene), U iso (H) = 1.5U eq (C) U iso (H) = 1.2U eq (C) respectively. H atoms of OH group of methanol molecules were detected in a difference Fourier and further refined with O-H = 0.82Å and subsequently treated as riding model with U iso (H) = 1.2U eq (O). H atoms of the amine group were located in a difference Fourier map and further refined with similarity restraints for d(N-H) and Uiso(H) = 1.2Ueq(N). One methanol molecule is disordered, with occupancies of 0.642 (9) and 0.358 (9).
Structure (1) has two molecules of methanol, one of them is disordered over two positions with degree of filling 0.64.
Unlike the title compound (2) the structure (1) has the OH protons of methanol connected by hydrogen bonds with oxygen atoms of morpholine rings (Fig.2). Important bond lengths for (1) are shown in the Table 2. The distances Cu-O are 1.907Å in average and metal-metal interatomic contacts are approximately 3.110 (1)Å, which is longer than the value for standard copper-copper bonds (2.64Å) ( van Niekerk et al., 1953). The angles values Cu-O-Cu 109.82 (18)Å suggest sp 3 -hybridization of the oxygen orbital.
The values of interatomic distances Cu-N, Cu-O and Cu-Cl agree well with reported ones for known complexes (Weinberger et al., 1998).
A packing diagram of the compound (see Fig.2) reveals that due to various types of hydrogen bonds the 3D polymer is formed. All four hydrogen atoms of the NH groups of the morpholine rings form straight N-H···O (Cl) hydrogen bonds (Table 3). In addition each of desorded OH group of methanol also involved in the formation of hydrogen bonds system. The morpholine residues exhibit orientations relative to the [Cu 4 (µ 4 -O)(µ 2 -Cl) 6 ] cores by which the Cu-bonded morpholine NH groups point with their N-H vectors halfway between two neighboring Cl ions. The methanol molecules do not interact directly with one of the copper coordination centers of the halide bridges.
We have noticed that the losses of methanol cause a decrease in crystalline of the substanstance as well as in (2) (Weinberger et al., 1998, Roy et al., 2010 . Solvate formation is relatively common in the family of the tetranuclear Cu-O-hal complexes and has been reported for more than 50 of the known crystal structures included in CCDC. At the end it must be noted that the [Cu 4 (µ 4 -O)(µ 2 -Cl) 6 ] core is quiet stable and is formed both as in the target synthesis, so as a side product of the various type reactions.  View of molecule [Cu 4 (µ 4 -O)(µ 2 -Cl) 6 (C 4 H 9 NO) 4 ]·2CH 3 OH]. All H atoms have been omitted.

Figure 2
Packing view diagram of (1).  Scheme of the reaction.  where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.45 e Å −3 Δρ min = −0.55 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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.