Potentiometric and spectrophotometric studies of MnII and NiII cimetidine complexes

Abstract

Cimetidine is an important hydrogen histamine receptor which has the ability to chelate metal ions in blood plasma and in different tissues. This study aimed to determine the stability constants for the cimetidine ligand with Mn II and Ni II metallic ions, synthesizing complexes and characterizing them by infrared spectroscopy, IR, and hydrogen nuclear magnetic resonance, 1 H NMR. Cimetidine protonation constant regarding to the imidazole group was logK 7.05 and the stability constants for Mn II and Ni II complexes, ML 2 species were logK 3.75 and 2.97, respectively, in 0.100 mol L -1 KCI. The interpretation of IR and H 1 NMR spectra for complexes Mn II -cim 2 and Ni II -cim 2 indicated that their formation occurs through the sulfur atoms in the thiol group, nitrogen atoms of imidazole ring, and nitrogen atoms of secondary amine. The nitrile group seems to be involved in the complexation of the Ni II -cim 2 complex.

Raman and SERS study on cimetidine–metal complexes with biomedical interest

“…Cimetidine ( cim ) is one of the most potent histamine H 2 ‐receptor antagonists for inhibiting excessive acid secretion caused by histamine and is currently used for treating peptic ulcers. It has been hypothesized that both its therapeutic effects, namely the anti‐inflammatory and anti‐ulcer properties, and the favorable evolution in rheumatoid arthritis as well as some of the side effects, such as male sexual dysfunctions frequently reported during treatment with cim , are mediated by its interaction with Cu(II) and Zn(II) metal ions 1–4 . Cim has a satisfactory superoxide dismutase (SOD) like activity too, so it may provide a possible therapeutic approach against prion diseases 5.…”

Recognition of the Enzymatically Active and Inhibitive Oxygenous Groups on WO3–x Quantum Dots by Chemical Deactivation and Density Functional Theory Calculations

“…As indicated, peaks at 849–534 cm –1 , 2984–2877 cm –1 , and 3500–3200 cm –1 were ascribed to the typical WO 3– x vibrations, CH vibration, and OH vibration, respectively. The FTIR spectrum of WO 3– x QDs-PH exhibited distinct vibration bands at 1640 and 1260 cm –1 , which should result from the formed CN and CN bonds in the deactivation process. , For the WO 3– x QDs-BA, an increasing peak intensity of the OCO at 1740 cm –1 can be obtained . Meanwhile, the intensity at 2984–2877 cm –1 , corresponding to stretching vibrations of the CH, were increased for the WO 3– x QDs-BrPE, which should result from the BrPE substituents.…”

The Critical Role of Ligand Flexibility on the Activity of Free and Immobilized Mn Superoxide Dismutase Mimics

“…The two additional signals observed at g eff = 5.2 and g eff = 2.8 are typical of Mn(II) with zero fields splitting slightly weaker than the X-band microwave frequency. The paramagnetic 1 H NMR spectrum of 2 in D 6 -DMSO shows the line broadening of pyridine and azomethine protons resonances that appear shifted ≈ 0.3 ppm compared to the free ligand (Figure 3c), confirming the Mn(II) coordination to these donor sites [43,[45][46][47]. The 1 H NMR spectral pattern of the complex in the 10-6 ppm region, shown in Figure 3c, comprises a set of four resonances at 8.5, 8.3, 7.9 and 7.4 ppm (linewidth in the range of 150 to 200 Hz) assigned to pyridine ring protons, and one relative sharp resonance at 8.2 ppm (w 1/2 = 50 Hz) attributed to the imine proton.…”