Search

Three new molecular complexes (phen)3(2-amino-Bz)2(H+)(BF4−)·3H2O 5, (phen)3(2-amino-5(6)-methyl-Bz)2(H+)(BF4−)·H2O 6, and (phen)(1-methyl-2-amino-Bz)(H+)(BF4−) 7, were prepared by self-assembly of 1,10-phenanthroline (phen) and various substituted 2-aminobenzimidazoles. Confirmation of their structures was established through spectroscopic methods and elemental analysis. The X-ray diffraction analysis revealed that the crystal structure of 7 is stabilized by the formation of hydrogen bonds and short contacts. In addition, the molecular geometry and electron structure of molecules 5 and 6 were theoretically evaluated using density functional theory (DFT) methods. According to the DFT B3LYP/6-311+G* calculations, the protonated benzimidazole (Bz) units act as NH hydrogen bond donors, binding two phenanthrolines and a BF4− ion. Non-protonated Bz unit form hydrogen bonds with the N-atoms of a third molecule phen. The molecular assembly is held together by π-π stacking between benzimidazole and phenanthroline rings, allowing for N-atoms to associate with water molecules. The complexes were tested in vitro for their tumor cell growth inhibitory effects on prostate (PC3), breast (MDA-MB-231 and MCF-7), and cervical (HeLa) cancer cell lines using MTT-dye reduction assay. The in vitro cytotoxicity analysis and spectrophotometric investigation in the presence of ct-DNA, showed that self-assembled molecules 5–7 are promising DNA-binding anticancer agents warranting further in-depth exploration. [ABSTRACT FROM AUTHOR]

Novel 4-amino-thieno[2,3-d]pyrimidine-6-carboxylates substituted at the second position were prepared by cyclocondensation of 2-amino-3-cyano-thiophene and aryl nitriles in an acidic medium. The design of the target compounds was based on structural optimization. The derivatives thus obtained were tested in vitro against human and mouse cell lines. The examination of the compound effects on BLAB 3T3 and MFC-10A cells showed that they are safe, making them suitable for subsequent experiments to establish their antitumor activity. The photoirritancy factor of the compounds was calculated. Using the MTT test, the antiproliferative activity to MCF-10A, MCF-7 and MDA-MB-231 cell lines was estimated. The best antiproliferative effect in respect to the MCF-7 cell line revealed compound 2 with IC50 4.3 ± 0.11 µg/mL (0.013 µM). The highest selective index with respect to MCF-7 cells was shown by compound 3 (SI = 19.3), and to MDA-MB-231 cells by compound 2 (SI = 3.7). Based on energy analysis, the most stable conformers were selected and optimized by means of density functional theory (DFT). Ligand efficiency, ligand lipophilicity efficiency and the physicochemical parameters of the target 4-amino-thienopyrimidines were determined. The data obtained indicated that the lead compound among the tested substances is compound 2. [ABSTRACT FROM AUTHOR]

New 1,3-disubsituted benzimidazol-2-ones are synthesized in order to evaluate their anti-trichinellosis efficacy. Solid-liquid phase transfer catalysis as the most readily available synthesis method was used to prepare the target compounds. The precursors required for the synthesis of the disubstituted benzimidazoles were obtained by means of two methods. Structures analysis of the compounds by means of IR, 1H NMR analysis was performed. The molecular geometry and electron structure of these molecules were evaluated using density functional theory (DFT) methods. Antitricinellosis activity of the compounds was investigated. The parasitological study in vitro showed that some of the tested benzimidazolones possessed higher activity against Trichinella spiralis than albendazole. The data of SAR for most of the tested compounds are comparable with those of albendazole. [ABSTRACT FROM AUTHOR]

The structural and spectral changes, arising from the conversion of a series of benzophenones into ketyls, are studied on the basis of standard DFT methods, employing different functionals and basis sets, without and with inclusion of solvent. Their relative predictive capabilities are evaluated by comparing the theoretically predicted and experimentally observed carbonyl frequencies. A very good agreement is achieved at combination between IEFPCM and ONIOM method with the basis functions 6-311+G(2df,p) for high layer and 6-311+G for low layer, showing the relevance of including high-order polarization functions in the basis set of high layer and solvent effect. The chosen level of theory ONIOM[B3LYP/6-311+G(2df,p)//6-311+G]-IEFPCM is applied to analyze the vibrational spectra, geometry and spin populations over the C O groups of the title species. The spin populations over the C O groups in ketyls correlate excellently with these decreases Δ ν CO and prove to be dominant factor determining the frequency variation in the IR spectra. [ABSTRACT FROM AUTHOR]

The FTIR spectra (4000–100 cm−1) and Raman spectra (3500–30 cm−1) of 2-[5,5-dimethyl-3-(2-phenyl-vinil)-cyclohex-2-enylidene]-malononitrile in solid state were measured. In addition, the structure and harmonic vibrational frequencies of this molecule were theoretically evaluated using B3LYP density functional methods. The computed vibrational frequencies are used to determine the types of molecular motions associated with each of the experimental bands observed. Bond length alternation (BLA) was established. Comparison with the experimental spectra provides important information about the ability of this computational method to describe the vibrational modes in this type of “push–pull” systems with potential non-linear optical applications. [Copyright &y& Elsevier]

In this paper three different “push-pull” 4-aminoazobenzene dyes have been synthesized in order to characterize their photochromic behavior in different solvents. The molecular geometry was optimized by DFT/B3LYP functional combined with the standard 6–31 + G(d,p) basis set for trans (E) and cis (Z) isomers and the energy levels of HOMO and LUMO frontier orbitals were computed using IEFPCM solvation in CHCl 3 and DMF. The calculated results were compared to the experimental optical band gap and HOMO values of cyclic voltammetry. The intramolecular six-membered hydrogen bond was formed in both isomers of the synthesized dyes. The thermodynamic parameters such as total electronic energy E (RB3LYP) , enthalpy H 298 (sum of electronic and thermal enthalpies), free Gibbs energy G 298 (sum of electronic and thermal free Gibbs energies) and dipole moment μ were computed for trans (E) and cis (Z) isomers in order to estimate the Δ E trans → cis , Δμ trans → cis, Δ H trans → cis , Δ G trans → cis and ΔS trans → cis values. The NBO analysis was performed in order to understand the intramolecular charge transfer and energy of resonance stabilization. The solvatochromic shift was evaluated by UV-VIS spectroscopy in CHCl 3 (nonpolar), EtOH (polar protic) and DMF (polar aprotic) solvents to determine the electron withdrawing and donating properties of the substituents on electron transitions energy. Through the increasing solvent polarity a strong bathochromic shift is observed. The photoisomerization experiments have been performed in two solvents CHCl 3 (nonpolar) and DMF (polar aprotic) by UV light irradiation with λ = 365 nm at equal concentrations and time of illuminations. The electronic spectra were computed by TD-DFT after geometry optimization using IEFPCM solvation in CHCl 3 and DMF. The degree of photoisomerization was calculated for the three azo chromophores in both solvents. By using first derivative of the UV-VIS spectra it was possible to resolve the overlapped electron transitions absorption bands. The existing intramolecular hydrogen bond in the azo chromophores was discussed in relation to the isomerization mechanisms and relative stability of the cis (Z) isomers. [ABSTRACT FROM AUTHOR]

In vitro antioxidant activity of two cyclodidepsipeptides, 3-(2-methylpropyl)-6-(propan-2-yl)-4-methyl-morpholine-2,5-dione and 3,6-di(propan-2-yl)-4-methyl-morpholine-2,5-dione, was investigated. Our data indicate moderate antioxidant potentials of the two studied cyclodepsipeptides. A high correlation between 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging capacity and total reducing power were found. According to the density functional theory (DFT) calculations, the most probable mechanism of antioxidant action is hydrogen atom abstraction from the activated C-H group at 3-position in the morpholinedione ring. To the best of our knowledge this is the first report about the antioxidant properties of morpholine-2,5-diones derivatives. [ABSTRACT FROM AUTHOR]