Zn(II) complexes with thiazolyl-hydrazones: molecular and crystal structures

Abstract

Sintetisana su i strukturno okarakterisana dva nova komplesa Zn(II) sa tiazolil-hidrazonskim ligandima HLS1 i HLS2. Iako su tokom sinteze primenjeni isti reakcioni uslovi, korišćena ista polazna so ZnCl2·2H2O i strukturno veoma slični ligandi, dobijeni su kompleksi različitih geometrija. Koordinacioni broj kompleksa 1-Cl sa HLS1 ligandom je pet, a geometrija je distorgovana kvadratna piramida (Slika 1). Kompleks 2-Cl ima koordinacioni broj šest i distorgovanu oktaedarsku geometriju (Slika 2). Molekulsku strukturu kompleksa 1-Cl čini centralni jon metala, jedan ligand (HLS1) koordinovan tridentatno preko NNN donorskih atoma piridina, imino grupe i 1,3-tiazolovog prstena, kao i dva koordinovana hloridna jona. Dobijeni kompleks je neutralan. Kod kompleksa 2-Cl za centralni jon metala su kooridnovana dva HLS2 liganda u neutralnom obliku, na isti način kao u slučaju kompleksa 1-Cl, što za posledicu ima formiranje katjonskog kompleksa čije je pozitivno naelektrisanje neutralisano ZnCl42– jonom. Kompleksi kristališu u monokliničnom kristalnom sistemu, ali u različitim prostornim grupama (1-Cl: P21/c i 2-Cl: C2/c). U kompleksu 2-Cl joni metala se nalaze u specijalnom položaju na osi 2 (Vikofov položaj e). Kristalno pakovanje oba kompleksa se zasniva na klasičnim N–H/Cl interakcijama. Eksperimenti difrakcije praha oba kompleksa potvrdili su da su dobijeni jednofazni proizvodi.

Two novel Zn(II) complexes with thiazolyl-hydrazones ligands HLS1 and HLS2, have been synthesized and characterized. Although the syntheses were performed under the same reaction conditions, using the same starting salt ZnCl2·2H2O and structurally very similar ligands, the geometries of the obtained complexes are different. The coordination number of the complex 1-Cl with HLS1 is five and the geometry is distorted square pyramidal (Figure 1). The complex 2-Cl has coordination number six and distorted octahedral geometry. Thus, the molecular structure of complex 1-Cl consists of one metal center, one HLS1 ligand coordinated tridentately via NNN atoms from pyridine, imine and 1,3-thiazole ring and two coordinated chloride ions. The obtained complex is neutral. The structure of complex 2-Cl consists of one metal center, two HLS2 ligands coordinated in the same way as in the previous complex. In this case the cationic complex is formed and the charge is balanced by ZnCl42–. Both complexes crystallize in a monoclinic crystal system, but in the different space groups (1-Cl: P21/c and 2-Cl: C2/c). Metal ions in 2-Cl are residing on a special position with site symmetry 2 (Wyckoff leter e). The crystal packing of these complexes is based on classical N–H/Cl hydrogen interactions. Powder X-ray diffraction experiments confirmed the presence of a single phase in both samples