Tetrakis[(3-hydroxypropyl)dimethylammonium] tetra-μ-acetato-κ8 O:O′-bis[chloridocuprate(II)](Cu—Cu) dichloride

The title compound (C5H14NO)4[Cu2(CH3COO)4Cl2]Cl2, consists of a pair of CuII ions bridged by four acetate groups, resulting in a Cu2(CH3COO)4 unit, four (3-hydroxypropyl)dimethylammonium cations (two crystallographically independent pairs) and two chloride anions. The Cu atoms at both termini are bonded to chloride anions. The latter are hydrogen bonded to one of the two pairs of crystallographically independent (3-hydroxypropyl)dimethylammonium cations. The Cu2(CH3COO)4 unit is located on a crystallographic inversion center, and the geometry around each metal center is close to octahedral. The Cl—Cu—Cu angles are nearly linear [177.48 (2)°] and the Cu—O bond lengths are in the range 1.9712 (18)–1.9809 (19) Å. The Cu⋯Cu separation between the two acetate-bridged CuII centers is 2.6793 (8) Å. The packing of the crystal structure is dominated by N—H⋯Cl hydrogen bonding between the ammonium groups and the chloride anions, as well as by O—H⋯O and O—H⋯Cl hydrogen bonds. One of the 3-hydroxypropyldimethylammonium cations shows orientational disorder with an occupancy ratio of 0.812 (4): 0.188 (4).


S1. Comment
In relation to our previous work on the structural chemistry of copper complexes (Shahid, Mazhar, Helliwell et al., 2008) we described here the crystal structure of the title compound. It consists of a centrosymmetric acetate bridged Cu 2 (CH 3 COO) 4 moiety with chloride anions at both termini, four (dimethylammonium)propanol cations and two chloride anions.
In the crystal structure the terminal chlorides are hydrogen bonded to one of crystallography independent (dimethylammonium)propanol cations ( Fig. 2 and Table 1). The other crystallographically indepenent dimethyl(3-hydroxypropyl) ammonium ion is disordered over two positions, with both moieties being approximate mirror images of each other (see refinement section for details). This disorder results in a significantlty different hydrogen bonding environment for the two moieties. The dominant orientation exhibits an N-H···Cl hydrogen bond of ca 2.15 Å between H1 and Cl2. The less prevalent moiety shows a much weaker bond with an N1B-H1B···Cl1 i bond distance of 2.53 Å (symmetry operator (i): - x + 1, y -1/2, -z + 3/2). The packing of the crystal structure is dominated by hydrogen bonding between the ammonium N -H units and the chloride (Cl2) anions, as well as O-H···O and O-H···Cl hydrogen bonds ( Fig. 3 and Table 1).

S2. Experimental
N,N-Dimethylaminopropanol (dmapH) (0.76 g, 7.43 mmol) and acetic acid (0.45 g, 7.43 mmol) were added to a stirred suspension of Cu(CH 3 COO) 2 .H 2 O (0.74 g, 3.72 mmol) and anhydrous CuCl 2 (0.50 g, 3.72 mmol) in 30 ml tetrahydrofuran (THF). After two hours stirring, the mixture was vacuum evaporated to dryness and the solid was redissolved in a minimum amount of THF to give green block-shaped crystals at room temperature after 10 days.

S3. Refinement
The crystal under investigation was found to be non-merohedrally twinned. The orientation matrices for the two components were identified using the program Cell Now (Sheldrick, 2005). The twin operation was found to be a two fold rotation around the a axis. The two components were integrated using Saint implemented in Apex2, resulting in a The data were corrected for absorption using Twinabs, and the structure was solved using direct methods with only the non-overlapping reflections of component 1. The structure was refined using the hklf 5 routine with all reflections of component 1 (including the overlapping ones) below a d-spacing threshold of 3/4, resulting in a BASF value of 0.118 (6).
The R int value given is for all reflections before the cutoff at d = 0.75 and is based on agreement between observed single and composite intensities and those calculated from refined unique intensities and twin fractions [Twinabs (Sheldrick, 2007)].
One of the 3-dimethylamine-propan-1-ol ligands shows orientational disorder with an occupancy ratio of 0.812 (4) to 0.188 (4), with both moieties being approximate mirror images of each other. Atoms N1, C5 and C6, which significantely overlap with their equivalent counterparts, were constrained to have the same ADPs as their equivalent partners in the minor moiety. No restraints were applied for non-hydrogen atoms.     where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.67 e Å −3 Δρ min = −0.66 e Å −3 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (