Aqua{tris[(1H-benzimidazol-2-yl-κN 3)methyl]amine}zinc 5-(dimethylamino)naphthalene-1-sulfonate perchlorate 2.5-hydrate

In the title compound, [Zn(C24H21N7)(H2O)](C12H12NO3S)(ClO4)·2.5H2O, the ZnII ion is in a distorted trigonal–bipyramidal coordination geometry. In the crystal, N—H⋯O and O—H⋯O hydrogen bonds connect the components into a two-dimensional network parallel to (001). In addition, there are weak C—H⋯O hydrogen bonds.

Herein we report its crystal structure.
In (I) (Fig .1), the Zn II ion is coordinated by four benzimidazole (bzim) N atoms of the NTB ligand and one O atom of H 2 O ligand, forming a five-coordinated distorted bipyramidal geometry. One amino N atom (N1) and one O atom (O1) of the H 2 O ligand occupy the axial positions, the other three bzim-N atoms (N2, N4 and N6) are located in the equatorial plane. All bond lengths and bond angles are as expected. In the crystal, N-H···O and O-H···O hydrogen bonds connect the components into a two-dimensional network parallel to (001). In addition there are weak intermolecular C-H···O hydrogen bonds (Fig. 2).

Refinement
All Hydrogen atoms were placed in calculated positions [C-H(methylene) = 0.97 Å, N-H(amine) = 0.86Å and C-H(aromatic) = 0.93 Å] and included in the refinement in a riding-motion approximation, with U iso (H)=1.5U eq (methyl C) and U iso (H)=1.2U eq (amine, methylene and aromatic C). Hydrogen atoms bonded to oxygen atoms were calculated and placed at their indicated positions in the difference maps and refined with O-H=0.82-0.83Å and U iso (H)=1.5U eq (O). The half occupancy water molecule is close to a twofold rotation axis.
supplementary materials sup-2 Figures Fig. 1. The molecular structure of (I), with displacement ellipsoids drawn at the 10% probability level. Hydrogen atoms are omitted for clarity.

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.