Dichlorido[(4E,11E)-5,7,12,14-tetrabenzyl-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene]cobalt(III) perchlorate

The CoIII atom in the title complex, [CoCl2(C40H48N4)]ClO4, is octahedrally coordinated within a trans-Cl2N4 donor set provided by the tetradentate macrocylic ligand and two chloride ions. The N—H atoms, which are orientated to one side of the N4 plane, form hydrogen bonds with chloride ions and perchlorate-O atoms. These along with C—H⋯O interactions consolidate the three-dimensional crystal structure. One of the benzene rings was disordered. This was resolved over two positions with the major component of the disorder having a site-occupancy factor of 0.672 (4).


Comment
In continuation of on-going studies of the synthesis, characterization and biological activities of substituted tetraazamacrocyclic ligands and their metal complexes (Bembi et al., 1990;Roy et al., 2007;Hazari et al., 2008;Roy et al., 2011a;Roy et al. 2011b), the synthesis and crystal structure of the title complex, (I), was investigated.
In (I), Fig. 1, the Co III atom exists within a trans-Cl 2 N 4 donor set defined by the four nitrogen atoms of the macrocyclic ligand and two chlorido atoms. The coordination geometry is based on an octahedron, with the greatest angular distortion manifested in the N2-Co-N3 angle of 83.81 (9)°. With respect to the central N 4 plane, the rings adopt three distinct orientations. Two rings adopt similar orientations lying approximately perpendicular and parallel to the N 4 plane: the dihedral angle between the N 4 and the C12-C17 and C20-C25 planes are 86.928 (8) and 78.645 (10) °, respectively. The C27-C32 ring is also orientated in a perpendicular fashion (dihedral angle = 88.921 (10)°) but lies to one side of the N 4 plane, with the C6-C26-C27-C28 torsion angle = 117.15 (4)°. The final ring is disordered over two positions. The major component is approximately planar with the N 4 donor set, forming a dihedral angle of 20.644 (10)°, whereas the minor component forms a dihedral angle of 13.400 (9) °, i.e. even more co-planar. Within the N 4 donor set, the two amine-H atoms are orientated to one side of the plane. The N2-H atom forms a contact with the perchlorate-O1 atom, and the N4-H forms an intramolecular N-H···Cl hydrogen bond, Table 2. These interactions along with several C-H···O contacts lead to the formation of supramolecular arrays in the ab plane. The layers stack along the c axis with the closest connection being of the type C-H···O, involving the perchlorate-O4 atom ( Fig. 2 and Table 1).

Experimental
The macrocyclic ligand, (4E,11E)-5,7,12,14-tetrabenzyl-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene (0.783 g, 1.0 mmol) was suspended in methanol (30 ml). Separately, cobaltous acetate (0.248 g, 1.0 mmol) was dissolved in methanol (30 ml). The combined solutions were heated on a water bath until the solution turned red. Concentrated HCl was added drop-wise so that the solution turned green. Then, about 1 ml HClO 4 was added whereupon a green product started to appear. The mixture was heated in order to reduce the volume to 15 ml. The resulting solution was kept at room temperature for about 1 h. The solid product, (I), was separated by filtration, washed with dry ethanol, followed by diethylether and dried in a vacuum desiccator over silica-gel. The yield was about 50%. The same complex was also prepared by using the acetonitrile as the solvent instead of methanol. However, the yield was about 42%. Green crystals of (I) were isolated from the slow evaporation of its methanol solution.

Refinement
The H-atoms were placed in calculated positions (C-H = 0.95-0.99 Å) and were included in the refinement in the riding model approximation, with U iso (H) = 1.2-1.5U eq (C). The N-H atoms were located from a difference map and refined with supplementary materials sup-2 N-H = 0.88±0.01 Å, and with U iso (H)= 1.2U equiv (N). The C35-C40 phenyl ring was found to be disordered over two positions with a dihedral angle of 24.9 (3) Å between the orientations. After anisotropic refinement (pairs of atoms were constrained to have equivalent anisotropic displacement parameters), the major component had a site occupancy = 0.672 (4). A number of reflections, i.e. (3 2 11), (6 0 6), (10 5 0), (3 2 10), (2 1 12) and (2 2 11), were omitted from the final refinement owing to poor agreement. Fig. 1. The molecular structure of (I) showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level. Only the major orientation of the disordered C35-C40 ring is shown.   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 Rfactors(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 )
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