Crystal structure of bis(2,2':6',2'-terpyridine)zinc(II) dinitrate dihydrate, [Zn(C15H11N3)2][NO3]2 · 2H2O

Abstract

Source of materialThe title complex was synthesized under hydrothermal conditions. A mixture of Zn(NO 3 ) 2 · 6 H 2 O (0.1485 g, 0.5 mmol), 2,2¢:6¢,2²-terpyridine (0.0124 g, 0.5 mmol; tpy), 8 ml deionized water was sealed in a Teflon-lined stainless steel vessel (25 ml) and heated at 413 K for 86 h under autogenous pressure, then cooled slowly to room temperature. Colorless block-shaped crystals were obtained by filtration. Experimental detailsThe occupancy factors for nitrate anion and the water molecule are 0.5 due to the disorder. All H atoms attached to C atoms were located from difference Fourier maps and refined using riding rigid body model. The water H atoms were also found and then refined using geometrical restraints. DiscussionCoordination complexes based on tridentate terpyridine-type ligands and octahedrally coordinated metal ions are of special interest as they reveal a range of interesting structural and physicochemical properties [1]. Meanwhile notably, 2,2¢:6¢,2²-terpyridine-based metal complexes have been used in this regard as well as in molecular devices and antitumor reagents [2][3][4]. In the present article, the structure of a stable zinc complex with two disordered nitrate ions and two water molecule is described. The zinc atom is irregularly six-coordinated by six N atoms from two tpy ligands and presents a distorted octahedral environment. All ZnN bond lengths are in the range of 2.084(4) Å 2.187(2) Å, which is similar to the corresponding bond length previously reported for [ZnN 6 ] (2.186 Å) [5]. The ligands act in a double-tridentate mode, with the coordination planes (defined by the three-bonded N atoms) being perpendicular to each other, subtending dihedral angles of 90.0°. A two-dimensional network is formed by the face-to-face p-p interactions (with centroidcentroid distances of 3.474 Å) of the pyridine ring and CH···O hydrogen bond (2.575 Å).