Crystal structure and spectroscopic properties of aqua­dichlorido­{1,1′-[(pyridine-2,6-diyl-κN)bis(methyl­ene)]bis­(4-butyl-4,5-di­hydro-1H-1,2,4-triazole-5-thione-κN2)}cobalt(II)

The structure of the title compound, [CoCl2(C19H27N7S2)(H2O)], at 173 K has monoclinic (C2/c) symmetry. We report here the synthesis, single-crystal structure, electrospray mass spectrum and NMR spectroscopy of a new six-coordinate cobalt(II) pincer complex. The pincer ligand, in this complex, which is novel, coordinates via three nitro­gen atoms (two triazole and one pyridine). The ligand is ambidentate and can coordinate via three nitro­gen atoms or two sulfur and one nitro­gen atoms. The cobalt(II) metal center has pseudo-octa­hedral geometry and based on the single-crystal structure, the pincer ligand coordinates in a meridional fashion with the metal and adjacent six-membered ring ligands all in a similar plane and forming two slightly distorted boat configurations. The other two coordinated monodentate ligands are one water mol­ecule and two chloride ions with four cobalt(II) complexes in the unit cell. The asymmetric unit of the complex is comprised of half the pyridine ring and water mol­ecule with the CoII atom at the center of the pincer situated about a twofold axis. The Co—N, Co—O, and Co—Cl bond lengths are consistent with single bonds. In the crystal, the complex forms a three-centre bifurcated weak hydrogen-bonding inter­action with a chlorine ion, forming one inter­molecular inter­action with the pincer group and a water mol­ecule and a second intra­molecular inter­action with a C—H group within the pincer group. Crystal packing is also highlighted with C22(6)>aa>a ring motifs, forming a three-dimensional supra­molecular network structure. While some stacking of the pyridine rings in the unit cell is observed, there are no relevant π–π inter­actions in the crystal packing. The 1H and 13C{1H} NMR spectra of the complex are consistent with a plane of symmetry being present. The electrospray mass spectrum, which was collected in positive ion mode, showed the loss of one water mol­ecule and one chloride ligand from the complex. In the future, we plan to screen this cobalt(II) complex for electrocatalysis reactivity.