Theoretical investigations of α,α,α-trifluoro-3, -p and o-nitrotoluene by means of density functional theory

Quantum chemical calculations and interpretation of electronic transitions and spectroscopic characteristics belonging to 1-(3-Mesityl-3-methylcyclobutyl)-2-(naphthalene-1-yloxy)ethanone

This comprehensive study reports the synthesis of the title compound, 1-(3-Mesityl-3-methylcyclobutyl)-2-(naphthalene-1-yloxy)ethanone (C26H28O2), and identification of the molecule by means of the standard experimental methods such as single-crystal X-ray diffraction, ultra violet-visible (UV-vis) spectra, Fourier transform infrared (FTIR) spectra, (13)C and (1)H NMR chemical shifts and quantum chemical calculations using density functional theory (B3LYP) method for the first time. The experimental results observed display that the synthesis of the C26H28O2 compound is perfectly conducted without any impurities. Additionally, the little deviations are noticed on the bond lengths and bond angles, confirming that the strong intra-molecular charge transfers appear in the due to the presence of the electron engagements and conjugative effects (bond weakening). Besides, the intermolecular C-H⋯O distance presents the interaction between the methylcyclobutyl C-H group and oxygen atom in the ethanone group. At the same time, the absorption wavelength (λmax) appears at 292 nm and interval 297-269 nm in the solvent of chloroform and THF as a consequence of the presence of effective π-π(∗) conjugated segments in the molecule studied. Besides, optical band gap energy of 3.22/3.25 eV (chloroform/THF), verifies the existence of the strong electronic donating groups in the structure. As for the quantum chemical computations, the determination of the optimized molecular structures, vibrational frequencies including infrared intensities, vibrational wavenumbers, thermodynamic properties, atomic charges, electronic transitions, dipole moment (charge distribution), optical band gap energy, (1)H and (13)C NMR chemical shifts are conducted using density functional theory/Becke-3-Lee-Yang-Parr (DFT/B3LYP) method with the standard 6-311++G(2d,2p) level of theory. The results obtained show that the strong intra-molecular charge transfer (ICT) appears between the donor and acceptor in the title compound due to the existence of the strong electronic donating groups and effective π-π(∗) conjugated segments with high electronic donor ability for the electrophilic attack (intermolecular interactions). Additionally, the presence of the non-uniform charge distributions (polar behavior) on the various atoms makes the title compound be useful to bond metallically.

Electrochemical and spectroscopic characteristics of p-acryloyloxybenzoyl chloride and p-acryloyloxybenzoic acid and antimicrobial activity of organic compounds

The purpose of this multidisciplinary work is to characterize title compounds, p-acryloyloxybenzoyl chloride (ABC) and p-acryloyloxybenzoic acid (ABA) by means of experimental and theoretical evidences. As experimental research, Fourier transformation-infrared spectra (in the region 400-4000 cm(-1)) and nuclear magnetic resonance (NMR) chemical shifts (with a frequency of 400 MHz) are examined for spectroscopic properties belonging to the new synthesized compounds. Moreover, the compounds are investigated for antimicrobial activity against various microorganisms (Gram-positive and Gram-negative) by means of the visual inhibition zone technique on the agar media. The experimental results observed indicate that ABA exhibits more powerful inhibitors of microorganisms due to the presence of the hydroxyl group leading to higher reactive system, one of the most striking features of the paper. As for the theoretical studies, the optimized molecular structures, vibrational frequencies, corresponding vibrational spectra interpreted with the aid of normal coordinate analysis based on scaled density functional force field, atomic charges, thermodynamic properties at different temperature, 1H NMR chemical shifts by way of density functional theory (DFT) with the standard (B3LYP) methods at 6-311G++(d,p) basis set combination for the first time. According to findings, the 1H NMR chemical shifts and vibrational frequencies are obtained to be in good agreement with the suitable experimental results. Thus, it would be more precise to say that the calculation level chosen is powerful approach for understanding in the identification of the molecules investigated. At the same time, we determine the electrochemical characteristics belonging to the samples via the simulation of translation energy (HOMO-LUMO), molecular electrostatic potential (MEP) and electrostatic potential (ESP) investigations. It is observed that the strong intra-molecular charge transfer (ICT) appears between the donor and acceptor in the both compounds (especially ABA) due to the existence of the strong electronic donating groups and effective π-π* conjugated segments with high electronic donor ability for the electrophilic attack (intermolecular interactions).

Investigation of solvent polarity effect on molecular structure and vibrational spectrum of xanthine with the aid of quantum chemical computations

The main scope of this study is to determine the effects of 8 solvents on the geometric structure and vibrational spectra of the title compound, xanthine, by means of the DFT/B3LYP level of theory in the combination with the polarizable conductor continuum model (CPCM) for the first time. After determination of the most-steady state (favored structure) of the xanthine molecule, the role of the solvent polarity on the SCF energy (for the molecule stability), atomic charges (for charge distribution) and dipole moments (for molecular charge transfer) belonging to tautomer is discussed in detail. The results obtained indicate not only the presence of the hydrogen bonding and strong intra-molecular charge transfer (ICT) in the compound but the increment of the molecule stability with the solvent polarity, as well. Moreover, it is noted that the optimized geometric parameters and the theoretical vibrational frequencies are in good agreement with the available experimental results found in the literature. In fact, the correlations between the experimental and theoretical findings for the molecular structures improve with the enhancement of the solvent polarity. At the same time, the dimer forms of the xanthine compound are simulated to describe the effect of intermolecular hydrogen bonding on the molecular geometry and vibrational frequencies. It is found that the CO and NH stretching vibrations shift regularly to lower frequency value with higher IR intensity as the dielectric medium enhances systematically due to the intermolecular NH⋯O hydrogen bonds. Theoretical vibrational spectra are also assigned based on the potential energy distribution (PED) using the VEDA 4 program.

Experimental and theoretical approaches for identification of p-benzophenoneoxycarbonylphenyl acrylate

The aim of this multidisciplinary study is to characterize a title compound, p-benzophenoneoxycarbonylphenyl acrylate (BPOCPA) synthesized by condensation reaction of p-acryloyloxybenzoyl chloride (ABC) with 4-hydroxybenzophenone (HBP) by means of experimental and theoretical evidences. The spectroscopic properties of the compound are experimentally examined by Fourier transformation-infrared (FTIR) spectra (in the region 400-4000 cm(-1)) and nuclear magnetic resonance (NMR) chemical shifts (with a frequency of 400 MHz). For the theoretical studies, the optimized molecular structures, vibrational frequencies including infrared intensities and Raman activities, corresponding vibrational spectra interpreted with the aid of normal coordinate analysis based on scaled density functional force field, atomic charges, thermodynamic properties, (1)H and (13)C NMR chemical shifts, JCH and JCC coupling constants belonging to the BPOCPA compound are analyzed in the ground state by the way of the density functional theory (B3LYP) with the standard 6-311++G(d,p) level of theory for the first time. All the results obtained show that the calculated vibrational frequencies and chemical shifts are observed to be in good agreement with the available experimental findings. According to the comparison between experimental results and theoretical data, the calculation level chosen plays an important role in understanding of dynamics of the title compound studied in this work. The self-consistent field (SCF) energy of the molecule in six different solvent media is also analyzed at the same basis set by applying both the Onsager and Polarizable Continuum Model (PCM). It is found that the SCF energies deduced from the methods reduce with the enhancement of the solvent polarity as a consequence of the increment in the stability of the compound studied. Besides, the changes of the PCM calculations are found to be higher than those of the Onsager ones, confirming that the former method displays a more stable structure than latter model.