Synthesis and characterization of the first zinc(II) complexes involving kinetin and its derivatives: X-ray structures of 2-chloro-N6-furfuryl-9-isopropyladenine and [Zn(kinetin)2Cl2]·CH3OH

A series of the first zinc(II) complexes of the general composition [Zn(Ln)2Cl2]·xSolv (1–5) involving kinetin [N6-furfuryladenine, L1, xSolv = CH3OH, complex 1] and its derivatives, i.e. N6-(5-methylfurfuryl)adenine (L2, xSolv = 2H2O, 2), 2-chloro-N6-furfuryladenine (L3, 3), 2-chloro-N6-(5-methylfurfuryl)adenine (L4, 4) and 2-chloro-N6-furfuryl-9-isopropyladenine (L5, 5), as N-donor ligands has been synthesized. The complexes have been fully characterized by elemental analyses (C, H, N), FTIR, Raman, 1H and 13C NMR spectroscopy, conductivity measurements, thermogravimetric (TG) and differential thermal (DTA) analyses. Single crystal X-ray analysis determined the molecular structures of 2-chloro-N6-furfuryl-9-isopropyladenine (L5) and the complex [Zn(L1)2Cl2]·CH3OH. The Zn(II) ion is tetrahedrally coordinated by two chlorido ligands and two molecules of the L1 organic compound. The two ligands L1 are coordinated to the central Zn(II) ion via the N7 atoms. This conclusion can also be drawn from multinuclear NMR spectroscopic experiments.