Structural characterization of a thiazoline-pyrazole ligand and its complexes with cobalt(II) and copper(II)

The structural characterization of 2-(pyrazol-1-yl)-2-thiazoline (PyTn) is reported. The complexes dichlorobis[2-(pyrazol-1-yl-κN)-2-thiazoline-κN]cobalt(II)-water (1/2) (1) and di-μ-chloro-bis{chloro[2-(pyrazol-1-yl-κN)-2-thiazoline-κN]}copper(II) (2) have been isolated and characterized through elemental analysis, IR, UV–Vis–NIR diffuse reflectance, X-ray diffraction and magnetic susceptibility, as well as, in the case of 2, by means of EPR. The environment around cobalt atom in 1 may be described as a distorted octahedron with the metallic atom coordinated to two thiazoline nitrogen atoms [Co–N(1) = 2.097(2) Å], two pyrazole nitrogen atoms [Co–N(3) = 2.157(2) Å] and two chloride ions [Co–Cl(1) = 2.472(1) Å]. With regard to 2, it can be said that its structure consists of dimeric [Cu2Cl4L2] molecules in which copper ions are bridged by two chloro ligands. The geometry about each copper ion approximates to a distorted square pyramid with each copper atom coordinated to one thiazoline nitrogen atom [Cu–N(1) = 2.012(2) Å], one pyrazole nitrogen atom [Cu–N(3) = 1.995(2) Å], one terminal chloro ligand [Cu–Cl(1) = 2.254(1) Å] and two bridging chloro ligands [Cu–Cl(2) = 2.218(1) Å, Cu–Cl(2a) = 2.906(1) Å].

The thiazoline derivative 2-(pyrazol-1-yl)-2-thiazoline (PyTn) yields two novel complexes, [CoCl2(PyTn)2] · 2H2O and [{CuCl(PyTn)}2(μ-Cl)2], by reaction with CoCl2 · 6H2O and CuCl2 · 2H2O, respectively, in ethanol-water solution. The crystal structure of the cobalt(II) complex reveals a distorted octahedral geometry around cobalt(II) ion, whereas the copper(II) complex presents a structure consisting of two square pyramids linked by one edge.Figure optionsDownload as PowerPoint slide