Taher S. Ababneh

New isomeric Cu(NO2-phen)2Br]Br complexes: Crystal structure, Hirschfeld surface, physicochemical, solvatochromism, thermal, computational and DNA-binding analysis

Water soluble mono-cationic copper(II) complex of the general formula [Cu(NO2-phen)2Br]Br, (NO2-phen=5-nitro-1.10-phenantholine) was prepared in good yield under ultrasonic irradiation. The desired complex was isolated as a bromide salt and identified by MS, EA, UV-Vis., TG/DTA, FT-IR and XRD. The single-crystal X-ray diffraction and Hirschfield analysis revealed a square pyramidal distorted geometry around the Cu(II) center. The geometry of the [Cu(NO2-phen)2Br]+ complex was fully optimized with ab-initio methods and (DFT/B3LYP) density functional theory, then structural parameters were compared to the XRD data. The solvatochromism of [Cu(NO2-phen)2Br]Br complex was investigated in several polar solvents. Absorption and viscosity titration studies concluded that the [Cu(NO2-phen)2Br]Br complex is a very good CT-DNA binder.

DFT computational studies, biological and antioxidant activities, and kinetic of thermal decomposition of 1,10-phenanthroline lanthanide complexes

Abstract[Ln (phen)2(NO3)3] complexes were synthesized by interaction of lanthanide nitrate {Ln (NO3)3.xH2O where Ln = Tb, Eu, Sm, Dy, and La} with 1,10-phenanthroline {phen} in ethylacetate. The complexes were characterized by several analytical and spectroscopic techniques. Density functional theory (DFT) calculations were carried out to optimize the geometries of all prepared complexes at the B3LYP/6-31G(d) level of theory. Vibrational frequencies of the complexes theoretically calculated were in good agreement with experimentally determined values. Most of the complexes exhibited high to moderate antibacterial and antifungal activities in vitro against seven different clinical isolates. The complexes were tested for their antioxidant activity toward 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical. Dy(III) complex showed the highest activity. Thermal degradation of complexes at different heating rates was investigated by thermogravimetric analysis (TGA). The complexes had high thermal stability. The activation energies (Ea) of the degradation were calculated by Kissinger and Flynn-Wall-Ozawa methods.

Structure, vibrations and relative stability of 1-methylcyclobutene and methylenecyclobutane tautomers using DFT and CCSD methods

In this study, geometrical optimizations, infrared spectroscopic analysis and relative stabilities of 1-methylcyclobutene and methylenecyclobutane tautomers were investigated by utilizing high-level ab initio and DFT calculations. The thermodynamic data showed that 1-methylcyclobutene is the more stable isomer with enthalpy H∼0.8kcal/mol and Gibbs energy G∼1.3kcal/mol lower than that for methylenecyclobutane at the M06/aug-cc-PVTZ level of theory. These results are in good agreement with the available experimental data. Additionally, the geometrical parameters and vibrational frequencies agree well with the recorded results in literatures.