The existence of two geometrical isomers (cis- and trans-) of a biologically significant pyrazoline derivative [5-(-1'-(4-bromo-phenyl)-3a',7a'-hexahydro-1'H-indazol-3'-yl)-3-methyl-1-phenyl-1H-pyrazole-4-carbonitrile] (PZ) has been established using a combined theoretical and experimental investigation. Solvatochromic analysis of PZ revealed the existence of said cis- and trans- isomers. The unique solvatochromic response of the PZ isomers and their preferential encapsulation within β-cyclodextrin (β-CD) nanocavity clearly shows the difference in the behavioral nature of the isomers of PZ in homogeneous and heterogeneous medium. Solvent polarity, time-resolved study, and anisotropy results also reinforce in favor of the existence of the isomers. To evaluate the actual orientation of cis and trans-PZ, the ground and excited state geometry of these isomers were optimized by the DFT/LanL2DZ and CIS/LanL2DZ methods, respectively. The experimentally observed results and the theoretically calculated results are found to be in close agreement.
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http://dx.doi.org/10.1021/jp307964z | DOI Listing |
J Phys Chem A
December 2024
Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea.
A photodetachment and photoelectron spectroscopic study by employing a cryogenically cooled ion trap combined with a velocity-map imaging setup has been carried out to unravel the vibrational structures and autodetachment dynamics of the dipole-bound states (DBSs) of -, -, and -methylphenolate anions (-, -, and -CHPhO). The electron binding energy of the DBS increases monotonically with the increase of the neutral dipole moment to give respective values of 66 ± 15, 123 ± 18, or 154 ± 14 cm for the -, -, or -isomer. The different electron-donating effects of the methyl moieties in the three geometrically different isomers seem to be reflected in the experiment.
View Article and Find Full Text PDFMagn Reson Chem
December 2024
Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece.
Detailed DFT studies of H and C NMR chemical shifts of hydroxy secondary oxidation products of various geometric isomers of conjugated linolenic acids methyl esters are presented. Several low energy conformers were identified for model compounds of the central dienenol OH moiety, which were found to be practically independent on the various functionals and basis sets used. This greatly facilitated the minimization process of the geometric isomers of conjugated linolenic acids methyl esters.
View Article and Find Full Text PDFSmall
December 2024
Science and Education Integration College of Energy and Carbon Neutralization, College of Materials Science and Engineering, Zhejiang Provincial Key Laboratory of Clean Energy Conversion and Utilization, Zhejiang University of Technology, Hangzhou, 310014, China.
The utilization of small organic molecules with appropriate functional groups and geometric configurations for surface passivation is essential for achieving efficient and stable perovskite solar cells (PSCs). In this study, two isomers, 4-sulfonamidobenzoic acid (4-SA) and 3-sulfamobenzoic acid (3-SA), both featuring sulfanilamide and carboxyl functional groups arranged in different positions, are evaluated for their effectiveness in passivating defects of the perovskite layer. The calculation and characterization results reveal that 3-SA, with its meta-substitution, offered superior passivation compared to the para-substituted 4-SA, leading to enhanced charge carrier dynamics and extraction efficiency.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou 434023, China.
We obtained the photoelectron spectra of Rh(CN) using the negative ion photoelectron velocity-map imaging (NI-PEVMI) technique and revealed the photodesorption process of Rh(CN). The vertical detachment energy (VDE) and adiabatic detachment energy (ADE) of Rh(CN) have both been experimentally reported to be 2.04 (3) eV.
View Article and Find Full Text PDFPhytochem Anal
December 2024
Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, Japan.
Introduction: Liquid chromatography-mass spectrometry (LC-MS) has enhanced the rapid, accurate analysis of complex plant extracts, eliminating the need for extensive isolation. Tandem mass spectrometry (MS/MS) further enhances this process by providing detailed structural information. However, differentiating structural isomers remains a challenge due to their minor spectral and structural differences.
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