Magnetic, structural and computational studies on transition metal complexes of a neurotransmitter, histamine

Kastas G., Pasaoglu H., Karabulut B.

JOURNAL OF MOLECULAR STRUCTURE, vol.1000, no.1-3, pp.39-48, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1000 Issue: 1-3
  • Publication Date: 2011
  • Doi Number: 10.1016/j.molstruc.2011.05.047
  • Journal Name: JOURNAL OF MOLECULAR STRUCTURE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.39-48
  • Keywords: Histamine, X-ray, Infrared spectroscopy, Electron paramagnetic resonance, Cu2+-doped, EFFECTIVE CORE POTENTIALS, SET MODEL CHEMISTRY, VIBRATIONAL-SPECTRA, CRYSTAL-STRUCTURE, MOLECULAR CALCULATIONS, COPPER(II) COMPLEXES, TOTAL ENERGIES, OXALATE, RAMAN, CADMIUM(II)
  • Ondokuz Mayıs University Affiliated: Yes

Abstract

In this study, the transition metal complexes of histamine (His) prepared with oxalate (Ox), that is, [Cu(His) (Ox)(H2O)], [Zn(His)(Ox)(H2O)] (or [Zn(His)(Ox)]center dot(H2O)), [Cd(His)(Ox)(H2O)(2)] and [Co(His)(Ox)(H2O)], are investigated experimentally and computationally as part of ongoing studies on the mode of complexation, the tautomeric form and non-covalent interactions of histamine in supramolecular structures. The structural properties of prepared complexes are experimentally studied by X-ray diffraction (XRD) technique and Fourier transform infrared (FT-IR) spectroscopy and computationally by density functional theory (DFT). The magnetic properties of the complexes are investigated by electron paramagnetic resonance (EPR) technique. The [Cu(His)(Ox)(H2O)] complex has a supramolecular structure constructed by two different non-covalent interactions as hydrogen bond and C-H center dot center dot center dot pi interactions. EPR studies on [Cu(His) (Ox)(H2O)], Cu2+-doped [Zn(His)(Ox)(H2O)] and [Cd(His)(Ox)(H2O)(2)] complexes show that the paramagnetic centers have axially symmetric g values. It is also found that the ground state of the unpaired electrons in the complexes is dominantly d(x2-y2) and unpaired electrons' life time is spent over this orbital. (C) 2011 Elsevier B.V. All rights reserved.