Spectroscopic Studies and DFT Calculations of Cimetidine Complexes with Transition Metal Ions

Abstract

The coordination behavior of the antiulcer drug cimetidine (cime) towards transition metal ions was investigated. The synthesis and characterization of [Cr(cime)<sub>2</sub>Cl<sub>2</sub>]Cl·3H<sub>2</sub>O, [Co(cime)Cl<sub>2</sub>]·5H<sub>2</sub>O, [Co(cime)<sub>3</sub>Cl]Cl·3H<sub>2</sub>O, [Ni(cime)Cl<sub>2</sub>(H<sub>2</sub>O)<sub>2</sub>]·H<sub>2</sub>O, [Cu(cime)Cl<sub>2</sub>]·2H<sub>2</sub>O, [Cu(cime)<sub>2</sub>Cl(H<sub>2</sub>O)]Cl·H<sub>2</sub>O, [Cu(cime)<sub>3</sub>Cl<sub>2</sub>]·3H<sub>2</sub>O, [Cu<sub>2</sub>(cime)Cl<sub>4</sub>], and [Zn(cime)Cl<sub>2</sub>]·1.5H<sub>2</sub>O are discussed, where cime acts as monodentate (imidazole N3) or bidentate ligand (N3 and S8). IR, UV-vis, EPR and NMR spectroscopies, mass spectrometry (FAB+), were employed for the characterization. In order to identify the most reactive areas of cimetidine, the electrostatic potential map of the ligand was calculated; also the structures of minimum energy of the coordination compounds were modeled using DFT (B3LYP/def2-TZVP) calculations.

Synthesis, Spectral Characterization and Thermal Behaviour of New Metal(ii) Complexes With Schiff Base Derived From Amoxicillin

“…The electronic spectra of the Co(II) complex displays two bands at 10150 cm -1 (n 1 ) and 22125 cm -1 (n 3 ), which are assigned to 4 T 1g (F)→ 4 T 2g (F)(n 1 ); 4 T 1g (F)→ 4 T 1g (P)(n 3 ) transitions, respectively. These are the characteristic bands of high spin octahedral Co(II) complexes 20 .…”

“…and also for their simple methods to be prepared. Many studies reported several metal complexes of Schiff base derived from different antibiotics and their biological activity [1][2][3][4][5][6][7][8] . In all these cases it was found that metal complexes showed increased antimicrobial activity than their parent Schiff bases.…”

Synthesis, Characterization and Biological Activity of Schiff Base Metal Complexes Derived from 2, 4-Dihydroxyactophenone

“…Electronic absorption spectroscopy transition metal complexes can bind to DNA through covalent bonding via replacement of a labile ligand of the complex by a nitrogen base of DNA such as guanine N 7 or non-covalent interactions such as intercalation, electrostatic, or groove binding 25 . Electronic absorption spectroscopy is one of the most useful techniques in DNA binding studies since the observed changes in the spectra may give indication of the mode of interaction.…”

A DFT study of the chemical reactivity of cimetidine A, C and D in the gas, H2O, MeOH and EtOH solvents

“…It was found through electrostatic potential maps that the more reactive zones of CimA are in the imidazolic nitrogen and the thioether sulfur. 19 Additionally, Singh et al found, at the B3LYP/6-31G*(d,p) level, that cimetidine is able to donate electrons through nitrogen and oxygen atoms to an acceptor molecule with empty and low energy orbital. 20 However, in spite of the interest dedicated to cimetidine from experimental and theoretical point of views, the chemical reactivity of cimetidine A, C and D at the molecular level in different solvents have not hitherto been analyzed.…”