Supramolecular complexes of Co(II), Ni(II) and Zn(II) p-hydroxybenzoates with caffeine: Synthesis, spectral characterization and crystal structure

Tasdemir E., Ozbek F. E. , Sertcelik M., HÖKELEK T. , Celik R. C. , Necefoglu H.

JOURNAL OF MOLECULAR STRUCTURE, cilt.1119, ss.472-478, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 1119
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1016/j.molstruc.2016.05.006
  • Sayfa Sayıları: ss.472-478


Three novel complexes Co(II), Ni(II) and Zn(II) containing p-hydroxybenzoates and caffeine ligands were synthesized and characterized by elemental analysis, FT-IR and UV-vis Spectroscopy, molar conductivity and single crystal X-ray diffraction methods. The thermal properties of the synthesized complexes were investigated by TGA/DTA. The general formula of the complexes is [M(HOC6H4COO)(2)(H2O)(4)]center dot 2(C8H10N4O2)center dot 8H(2)O (where: M: Co, Ni and Zn). The IR studies showed that carboxylate groups of p-hydroxybenzoate ligands have monodentate coordination mode. The M2+ ions are octahedrally coordinated by two p-hydroxybenzoate ligands, four water molecules leading to an overall MO6 coordination environment. The medium-strength hydrogen bondings involving the uncoordinated caffeine ligands and water molecules, coordinated and uncoordinated water molecules and p-hydroxybenzoate ligands lead to three-dimensional supramolecular networks in the crystal structures. (C) 2016 Elsevier B.V. All rights reserved.