Zinc(II) chlorido complexes of protonated kinetin and its derivatives: Synthesis, properties and X-ray structure of [Zn(Hkinetin)Cl3]·kinetin

The syntheses and characterization of five novel zinc(II) complexes with protonated kinetin (6-furfurylaminopurine) and its derivatives are described. Based on the results following from elemental analyses (C, H, N), FTIR, Raman, 1H and 13C NMR spectroscopy, conductivity measurements, thermogravimetric (TG) and differential thermal analyses (DTA), and single crystal X-ray analysis, the complexes of the general composition [Zn(HLn)Cl3]·xLn (1–5) have been prepared, where L1 = kinetin (6-furfurylaminopurine), L2 = 6-(5-methylfurfurylamino)purine, L3 = 2-chloro-6-furfurylaminopurine, L4 = 2-chloro-6-(5-methylfurfurylamino)purine and L5 = 2-chloro-6-furfurylamino-9-isopropylpurine, and x = 1/2–2. The structure of [Zn(HL1)Cl3]·L1 (1) has been determined by single crystal X-ray analysis. The Zn(II) atom is tetrahedrally coordinated by three chlorido ligands and one N3-protonated organic molecule forming a ZnCl3N donor set. The organic ligand L1 is coordinated to the Zn(II) centre through the N7 atom of the purine moiety. NMR spectroscopic study confirmed the N3 and N7 atom to be the protonation, and coordination site, respectively.