MESP Surfaces Research Articles

Synthesis, structural elucidation, physico-chemical quantum properties and in silico interaction analysis of 2-methyl-3-((4-nitrobenzyl)oxy)quinoxaline

MNBQ has been synthesized and its crystal structure was solved by direct method and refined by full matrix least squares procedure. The crystal structure is stabilized with elaborate network of intermolecular CH…O hydrogen bonds and van der-Waal's forces to form supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots were analysed for non-covalent interactions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H···H (37.5 %) and O···H/H···O (21.8 %) interactions. Theoretical (DFT) studies on the molecular structure, vibrational spectra, Mulliken charges, HOMO, LUMO, MESP surfaces have been performed at B3LYP /6-311++G (d,p) level of theory. The geometrical parameters of the optimized compound are in good agreement with the XRD experimental data. Molecular docking studies supported by in silico drug likeness screening suggested that MNBQ might possess potent cancer chemopreventive activity.

Synthesis, spectral, antifungal, in silico molecular docking, ADME and DFT studies of some 2-(2-hydrazineyl)thiazole derivatives: Computational and experimental perspective

A series of thiazole Schiff bases (4a-4q) is synthesized and evaluated for the antibiofilm potential against fungal species C. albicans. The compounds 4a, 4b, 4c, 4p and 4q showed significant antibiofilm activity. Compounds 4a, 4b and 4c showed antibiofilm activities at 100 µg/mL concentrations, whereas 4p, and 4q showed activities around 50 µg/mL concentrations. Microscope study also supports the antibiofilm activity of compounds 4a,4b,4c, 4p and 4q. Molecular mechanism of action of bioactive derivatives for antibiofilm activities was studied by analysing the expression levels of some genes involved in the biofilm formations via qPCR. The molecular docking simulations with CYP51 revealed these compounds interact via hydrophobic and Van der Waals binding. The MESP surfaces were plotted using DFT method which also supported the molecular docking interactions.The ADME profile of these compounds revealed favourable pharmacological characteristics.

Synthesis, Crystal Growth, and Computational Investigation of New Tetrahydroisoquinoline Derivatives Potent against Molecule Nitric Oxide Synthases

In the present work, we describe the synthesis of new tetrahydroisoquinoline derivatives and the crystal structures of two of them. Density functional theory (DFT) investigations at the B3LYP/6-31+G(d,p) level provided their structural reactivity and nonlinear optical properties. The low HOMO-LUMO gaps (EH-L) suggest a soft nature and higher reactivity, while calculated global reactivity descriptors provide assessments of their reactivity and electronic stability. The calculated natural bonding molecular orbital (NBO) charges show excellent charge separation (charge transfer) and identify the donor and acceptor parts of the molecules. Density of states (DOS) analyses show the newly generated energy states and reduced band gaps, which impart higher conductive properties. For surface reactivity, 3D MESP surfaces are plotted and show electron-rich sites near the nitrogen atoms of the tetrahydroisoquinoline rings. Nonlinear optical (NLO) properties of the crystals are predicted from calculated polarizability (αo) and hyperpolarizability (βo) values. For IVb, the αo and βo values are 415.53 and 1003.44 au. The remarkable value (1003.44 au) of the hyperpolarizability (βo) shows IVb has excellent NLO properties. Structural activity relationship analysis suggests that nitric oxide synthases are better targets for both compounds, and they were further subjected to molecular docking simulations to understand the binding efficiency. In addition, ADMET analyses were carried out to understand the potential activity of the molecules as drug candidates.

Crystallographic structure, quantum and in silico interaction analysis of 3-(benzylthio)-4-hydroxy-2H-chromen-2-one

A biologically promising new molecule, 3-(benzylthio)-4-hydroxy-2H-chromen-2-one has been synthesized following visible light-induced protocol in the presence of singlet molecular oxygen. Its detailed spectral properties and X-ray crystal structure are studied. The crystal structure is solved by direct method and refined to a final R value of 0.0701. The crystal structure is stabilized by an elaborate system of hydrogen bonds along with π–π and Van der Waal’s forces to form supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots are analyzed for non-covalent interactions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H…H (38.2%) and C···H/H···C (22.4%) interactions. Energy framework analysis allowed us to quantify different contributions to the overall energy. Theoretical (DFT) studies on the molecular structure, Mulliken charges, HOMO, LUMO, MESP surfaces have been performed at B3LYP/6-311 + G(d,p) level of theory. The molecular docking studies are performed to get insights into the inhibition nature of this molecule against CDKS protein and for searching new anticancer agents. Pharmacological analysis was carried out in-order to check the bioactive nature of synthesized compound.

Synthesis, characterization, Hirshfeld surface analysis and molecular docking studies of 3-(cyclohexylthio)-4-hydroxy-6-methyl-2H-chromen-2-one

The 3-(cyclohexylthio)-4-hydroxy-6-methyl-2H-chromen-2-one (mf. C16H18O3S), a biologically relevant new version of organo-sulfur compounds, has been synthesized Its detailed spectral properties and X-ray crystal structure are studied. The crystal structure was solved by direct method and refined by full matrix least squares procedure to final R value of 0.0468. The crystal structure is stabilized by elaborate system of O-H···O, C-H···O, O-H···S hydrogen bonds to form supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots were analyzed for molecular interactions. The Hirshfeld surface analysis of the crystal structure indicates H…H and C···H/H···C interactions as the most important contributors to the crystal packing. Theoretical (DFT) studies on the molecular structure, HOMO, LUMO, MESP surfaces have been performed at B3LYP/6-311 + G(d,p) level of theory. The molecular docking studies have been performed to get insights into the inhibition nature of this molecule against CDKS protein, and search for new anticancer agents. Pharmacological analysis was carried out inorder to check the bioactive nature of the synthesized compound.

Synthesis, molecular structure, electronic, spectroscopic, NLO and antimicrobial study of N-benzyl-2-(5-aryl-1,3,4-oxadiazol-2-yl)aniline derivatives

The cyclization reaction between two benzohydrazides with 2-(benzylamino)benzoic acid afforded the novel 2,5-disubstituted oxadiazole derivatives; N-benzyl-2-(5-phenyl-1,3,4-oxadiazol-2-yl)aniline (NBPOA) and N-benzyl-2-(5-(4-chlorophenyl)-1,3,4-oxadiazol-2-yl)aniline (NBCPOA). Theoretical investigation of these newly synthesized oxadiazole derivatives was carried out by density functional theory (DFT) method at the B3LYP/6-311++G(d,p) level of theory. TD-DFT computations were performed to have insights into the three singlet electronic states of the electronic absorption spectra and to assign and correlate with the experimental UV-Vis spectra. The electronic absorption measurements were done in DCM and DMSO solvents. The increase in solvent polarity exerted a blue shift on the first singlet electronic excited state and a red shift on the second and the third electronic excited states suggesting different polarities of the excited states. Vibrational band assignments were scaled and compared with the experimental frequencies. Structural parameters and chemical reactivity such as HOMO and LUMO energies, MESP surfaces, Mulliken charges, and global reactivity descriptors were analyzed. It was observed that NBCPOA has a smaller HOMO-LUMO energy gap and larger global softness than NBPOA. The charge transfer that takes place in NBPOA and NBCPOA is supported by the oscillator strength. These compounds were also screened for their in vitro antibacterial activity against two Gram-negative bacterial strains namely Escherichia coli and Salmonella typhi and two Gram-positive bacterial strains namely Bacillus subtilis and Bacillus megaterium and antifungal activity against Aspergillus niger, Rhizopus oryzae, Penicillium chrysogenum, and Candida albicans fungal strains. The synthesized compounds exhibited moderate antibacterial and antifungal properties.

Antimicrobial and computational investigation of two 2,3‐dihydro‐1H‐inden‐1‐one derived fluorinated chalcone motifs

AbstractIn this work, we report the anti‐microbial and computational study of two 2,3‐dihydro‐1H‐inden‐1‐one derived fluorinated chalcone scaffolds. The (E)‐2‐(4‐(trifluoromethyl)benzylidene)‐2,3‐dihydro‐1H‐inden‐1‐one (TFMBD‐1) and (E)‐2‐(4‐(trifluoromethoxy)benzylidene)‐2,3‐dihydro‐1H‐inden‐1‐one (TFMBD‐2) were synthesized by Claisen‐Schmidt reaction. The in‐depth structural analysis of optimized molecular structures, bond lengths and bond angles has been discussed by using density functional theory (DFT) with B3LYP/6‐311++G(d,p) basis set. The geometrical parameters, frontier molecular orbitals, global reactivity parameters, and MESP surfaces were all predicted using the same basis set on completely optimized geometries. Ionization potential, electron affinity, electronegativity, chemical hardness, global softness, global electrophilicity, and chemical potential were calculated using HOMO and LUMO energy values. Besides, the synthesized compounds were screened for their in‐vitro antibacterial and antifungal study. Antibacterial activity was screened against two Gram‐negative bacteria, E. coli and P. vulgaris, as well as against two Gram‐positive bacteria, S. aureus and B. subtilis, and antifungal activity was evaluated against A. niger and C. albicans. The TFMBD‐1 was revealed to be a more effective antibacterial and antifungal agent than TFMBD‐2.

Synthesis, Characterization, Crystal Structure, Molecular Docking Analysis and Other Physico-Chemical Properties of (E)-2-(3,4-Dimethoxystyryl)Quinoline

A biologically active heterocyclic compound (E)-2-(3,4-dimethoxystyryl)quinoline has been synthesized. Detailed 1H NMR, 13C NMR spectra and elemental mass analysis has been carried out. The single crystal X-ray studies revealed that the asymmetric unit of the compound contains two crystallographically independent molecules with almost similar geometries and the compound crystallizes in a monoclinic space group P 21/c, Z = 8. The crystal structure is stabilized with elaborate network of intermolecular C–H…O hydrogen bonds, C–H…π, π–π and van der-Waal’s forces to form supramolecular structures. 3D Hirshfeld surfaces and allied 2D fingerprint plots were analyzed for non-covalent interactions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H…H (41.8%) and C···H/H···C (39.9%) interactions. Theoretical (DFT) studies on the molecular structure, vibrational spectra, Mulliken charges, HOMO, LUMO, MESP surfaces have been performed at B3LYP/6-311++G (d,p) level of theory. The geometrical parameters of the optimized compound are in good agreement with the XRD experimental data. Molecular docking studies supported by in silico drug likeness screening explored the promising anti-Alzheimer's activity of this N-containing bioactive styryl-quinoline, which could be considered as a lead compound for anti-Alzheimer's drug design.

Synthesis, Computational, Antibacterial and Antifungal Investigation of Two Tri-Fluorinated Chalcones of 1-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)ethan-1-one

In the present study, we report the combined experimental and computational study along with antimicrobial screening of two tri-fluorinated chalcones from 1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)ethan-1-one. The (E)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(4-(trifluoromethyl)phenyl)prop-2-en-1-one (DBTFP-1) and (E)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(4-(trifluoromethoxy)phenyl)prop-2-en-1-one (DBTFP-2) were synthesized by the famous Claisen-Schmidt condensation reaction. The computational investigation of optimized molecular structures, bond lengths and bond angles were performed by using density functional theory (DFT) with a B3LYP functional and 6-31G(d,p) basis set. The electronic properties were computed using Time-Dependent density functional theory (TD-DFT) with a B3LYP functional and 6-31G(d,p) basis set for the optimized geometries. The lower band gap in DBTFP-1 demonstrated the inevitable intramolecular charge transfer. The UV-Visible simulations were performed in the gas phase and dichloromethane (DCM) solvent. The experimental UV-Visible analysis was performed in DCM solvent. The first singlet excited state was attributed to the n-π* and second singlet excited state to the π -π* electronic transition. The scaled vibrational bands of titled compounds were compared with experimental observations and correct vibrational assignments were made. Various global reactivity parameters were analyzed and discussed to apprehend the chemical behavior of the synthesized chalcones. MESP and contour surfaces revealed negative potentials near the oxygen atoms and positive potentials over the hydrogen atoms. Mulliken charge study revealed that C17 and C33 are the most negative and positive carbon atoms in DBTFP-1, respectively, whereas C17 and C35 are the most negative and positive carbon atoms in DBTFP-2. The antibacterial activity was performed against P. vulgaris and S. aureus and antifungal activity against A. niger and C. albicans. The antimicrobial activity for these two compounds was correlated with LUMO and band gap energy. The magnificent antimicrobial activity of DBTFP-1 was attributed to its more stabilized LUMO and lower band gap than DBTFP-2.

Facile protic hydration of acetonitrile to protonated acetamide at oxygen mediated by chloroauric acid: insights from experimental and calculations

Chemical transformations such as nitrile hydration or carbon–oxygen bond formation reactions under gentle conditions are important in the pharmaceutical industry because of the presence of potentially delicate functional groups. We present a non-catalytic hydration reaction of acetonitrile to the corresponding protonated acetamide gold(III) salt [CH3(OH)NH2]AuCl4 under ambient conditions in water using chloroauric acid H[AuCl4] for the first time. ATR-FTIR, Raman and 1H and 13C NMR spectroscopic data in addition to X-ray crystallography supported the isolation of protonated acetamide stabilized with [AuCl4]− anion. The protonation of N–C=O fragment of acetamide, O- versus N-protonation aptitude, was validated experimentally and theoretically. The X-ray crystal structure of the acetamide salt [CH3C(OH)NH2]AuCl4 in the triclinic Pī space group suggested the enolic form. However, the reaction of gold(III) trichloride AuCl3 with acetonitrile in water in the absence of a proton source formed the gold(I)/gold(III) salt [Au(CH3CN)2]AuCl4 without hydration as shown in X-ray structure in the monoclinic P21/c space group. Mapping of HOMO–LUMO energy gap using frontier molecular orbital theory and MESP surfaces of OH and NH conformers of acetamide from DFT calculations clearly shows subsequent changes in their profiles with the change in their protonation states. An energy gap of 56.4 kcal/mol in the optimized energies of OH and NH conformers of acetamide along with computed HOMO–LUMO energy difference represents the relative stability of OH conformer compared to NH conformer, thus leading to the conclusion that OH protonation site is more likely to exist in the acetamide structure as compared to the NH protonation state.

Experimental and quantum chemical studies on poriferasterol – A natural phytosterol isolated from Cassia sophera Linn. (Caesalpiniaceae)

Poriferasterol, a biologically relevant phytosterol, has been isolated and identified first-time from Cassia sophera Linn. (family: Caesalpiniaceae) based on detailed spectral studies. Exhaustive theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces and reactivity descriptor of this plant-derived natural molecule have been performed. The experimentally observed FT-IR spectrum of the title compound has been compared with spectral data obtained by DFT-B3LYP/6-311 + G (d,p) method. The UV–visible spectrum of the title compound has also been recorded and the electronic properties, such as frontier orbitals and band gap energy are measured by TD-DFT approach. The 1H and 13C NMR spectrum has been calculated by using the gauge independent atomic orbital method and compared with the observed data.

Structural confirmation, single X-ray crystallographic behavior, molecular docking and other physico-chemical properties of gerberinol, a natural dimethyl dicoumarol from Gerbera lanuginosa Benth. (Compositae)

The proposed structure of gerberinol (1), a naturally occurring dimethyl dicoumarol, has been conclusively established on the basis of its detailed spectral and single crystal X-ray analyses. The compound, C21H16O6, crystallizes in the monoclinic space group P21/c with the following unit-cell parameters: a = 14.0884(14), b = 15.1746(15), c = 7.6392(8)Å, α = 90.00°, β = 98.949(4)°, γ = 90.00° and Z = 4. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 11.43 for 2377 observed reflections. Exhaustive theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces, and molecular docking of this plant-derived natural molecule have also been performed. The equilibrium geometry of the title compound has been obtained and analyzed using DFT-B3LYP/6-311 + G(d,p) method. Molecular docking study of the molecule for predicting its possible biological activities revealed that the compound might be a potent antimicrobial, neurodegenerative and anticancer agent as evidenced from its excellent FF (full fitness) score for 1FUJ and 1ZX1 enzymes.

Quantum chemical studies on cocsuline using density functional theory and its docking into dihydrofolate reductase receptor

Cocsuline, a biologically active natural product, is biosynthetically related to the more common bisbenzyliso- quinoline alkaloids. We perform a comprehensive quantum chemical analysis on cocsuline using density functional theory at B3LYP/6-311G(d,p) level. The equilibrium molecular structure of cocsuline has been obtained. The weak intra-molecular C-H... O interaction is recognized, characterized and quantified by quantum theory of atoms in molecule (QTAIM). The chemical reactivity of cocsuline is explained and discussed with the help of HOMO, LUMO and MESP surfaces. The vibrational infrared spectrum of cocsuline has been calculated and prominent vibrational modes have been assigned. A good agreement between our calculated wavenumbers and experimentally reported values has been observed. The molecular docking of cocsuline into dihydrofolate reductase receptor shows that it may inhibits this enzyme and acts as an effective antimalarial drug.

3,5,7-Trimethoxyphenanthrene-1,4-dione: a new biologically relevant natural phenanthrenequinone derivative from Dioscorea prazeri and studies on its single X-ray crystallographic behavior, molecular docking and other physico-chemical properties

A naturally occurring new phenanthrenequinone derivative has been isolated from the yams of Dioscorea prazeri Prain and Burkil (Dioscoreaceae) and identified as 3,5,7-trimethoxyphenanthrene-1,4-dione (1) on the basis of its detailed spectral and single crystal X-ray analyses. The compound crystallizes in the triclinic space group P with the following unit-cell parameters: a = 7.7045(3), b = 8.5088(4), c = 16.3254(7) A, α = 98.908(2)°, β = 96.316(2)°, γ = 103.939(2)° and Z = 2. The crystal structure was solved by direct methods using single-crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R-value of 0.0559 for 2832 observed reflections. Exhaustive theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces, reactivity descriptor and molecular docking of this plant-derived hitherto unknown natural molecule have also been performed. The equilibrium geometry of the title compound has been obtained and analyzed using the DFT-B3LYP/6-31+G(d,p) method. A comparison between the calculated vibrational spectral data with the experimental observations for the phenanthrenequinone molecule has been performed. The reactivity of this molecule is explained using various local as well as global molecular descriptors and reactivity surfaces have also been analyzed. The molecular docking study of the title molecule for predicting its possible anticancer property has also been investigated.

Conformational stability, molecular structure, vibrational, electronic, 1H and 13C spectral analysis of 3-pyridinemethanol using ab-initio/DFT method

The FT-IR and FT-Raman spectra of 3-pyridinemethanol (3PYRM) have been recorded in the regions 4000–400 and 4000–100 cm−1 respectively. The vibrational analysis of 3PYRM was carried out using wavenumbers computed by HF and DFT (B3LYP) methods with 6-311++G (d, p) basis set, along with experimental values. The conformational analyses were performed and the energies of the different possible conformers were determined. The total electron density and MESP surfaces of the molecules were constructed using B3LYP/6-311++G (d, p) method to display nucleophilic and electrophilic region globally. The HOMO and LUMO energies were measured and different reactivity descriptors are discussed the active sites of the molecule. Natural Bond Orbital Analysis is discussed and possible transition are correlated with the electronic transitions. Milliken's net charges and the atomic natural charges are also predicted. The 13C and 1H NMR chemical shifts were computed at the B3LYP/6-311++G (2d, p) level by applying GIAO theory and compared with the experimental spectra recorded using the high resolution of 100 MHz and 400 MHz NMR spectrometer with electromagnetic field strength 9.1T, respectively. The temperature dependence of the thermodynamic properties; heat capacity, entropy and enthalpy for the title compounds were also determined by B3LYP/6-311++G (d, p) method.

Structural, Electronic Properties, Hydrogen Bonding Analyses, and Biological Activity of Two Multiple Myeloma Drugs: Lenalidomide and Pomalidomide

In this article, we made a comparative study of two multiple myeloma drugs: lenalidomide and pomalidomide. We calculated and discussed their geometries at DFT/B3LYP method. Intra-molecular hydrogen bonding in these molecules is confirmed and characterized by QTAIM calculations. Electronic parameters along with HOMO-LUMO and MESP surfaces are calculated in order to compare their chemical reactivity. The effect of structure and bonding on electronic properties and biological activities is discussed and it is established that pomalidomide is more biologically active than lenalidomide. The phenyl ring of these molecules show teratogenic effects, making a possibility of finding another new class of drugs.

Combined experimental (FT-IR, UV–visible spectra, NMR) and theoretical studies on the molecular structure, vibrational spectra, HOMO, LUMO, MESP surfaces, reactivity descriptor and molecular docking of Phomarin

Phomarin is an important natural product belonging to anthraquinone series of compounds. The equilibrium geometry of phomarin has been determined and analyzed at DFT method employing B3LYP/6-311++G(d,p) level of computation. The reactivity of molecule using various descriptors such as Fukui functions, local softness, electrophilicity, electronegativity, Hardness, HOMO–LUMO gap are calculated and discussed. The infrared and UV–vis spectra of phomarin are calculated and compared with the experimentally observed ones. Moreover, 1H and 13C NMR spectra have been calculated by using the gauge independent atomic orbital method. We also notice that phomarin shows remarkable biological activities against malaria parasite. The study suggests further investigation on phomarin for their pharmacological importance.

Vibrational spectra, HOMO, LUMO, MESP surfaces and reactivity descriptors of amylamine and its isomers: A DFT study

Amylamine constitutes an important class of organic compounds which exists in a variety of ammonia derivatives. In present study, a comparative analysis of amylamine and its two potential isomers, iso-amylamine and tert-amylamine, has been performed using density functional theory with B3LYP method and 6-311G(d,p) as the basis set. The equilibrium structures of amylamine as well as its iso and tert forms have been obtained. The vibrational spectroscopic analysis has been carried out for the three molecules and complete assignments to all possible modes have been offered. The HOMO, LUMO and MESP surfaces are analyzed to discuss the chemical reactivity patterns in the molecules. A number of reactivity parameters have been calculated to further explain their chemical reactivity. The thermodynamic and nonlinear optical parameters are also calculated and discussed.

FT-IR spectroscopy, intra-molecular C−H⋯O interactions, HOMO, LUMO, MESP analysis and biological activity of two natural products, triclisine and rufescine: DFT and QTAIM approaches

The present study deals with two natural products, triclisine and rufescine which are extracted from the Amazonian wines but ubiquitous in nature. The quantum chemical density functional method at B3PW91/6-311+G(d,p) level is used to obtain the equilibrium geometries of these molecules. The quantum theory of atoms-in-molecule approach is employed to study various intra-molecular C−H⋯O interactions within these molecules. We have also performed vibrational analyses of triclisine and rufescine at their equilibrium geometries and presented the complete assignments of the significant vibrational modes. The calculated vibrational frequencies are shown to be in perfect agreement with the experimentally observed FTIR spectra of molecules under study. In addition, the electronic properties of these molecules are also discussed with the help of HOMO–LUMO and MESP surfaces and a number of electronic as well as thermodynamic parameters are calculated which are closely related to their chemical reactivity and reaction paths. The biological activities of both molecules have also been predicted which highlight their pharmacological importance.

Normal Modes, Molecular Orbitals and Thermochemical Analyses of 2,4 and 3,4 Dichloro Substituted Phenyl-N-(1,3-thiazol-2-yl)acetamides: DFT Study and FTIR Spectra

A detailed spectroscopic analysis of two dichloro substituted phenyl-N-(1,3-thiazol-2-yl)acetamides at 2,4 and 3,4 positions of the phenyl ring has been carried out by using B3LYP method with 6-31+G(d, p) basis set within density functional scheme. The scaled theoretical wave numbers are in perfect agreement with the experimental values and the vibrational modes are interpreted in terms of potential energy distribution (PED). The internal coordinates are optimized repeatedly to maximize the PED contributions. The molecular HOMO-LUMO surfaces, their respective energy gaps, and MESP surfaces have also been drawn to explain the chemical activity of both molecules. Various thermodynamic parameters are presented at the same level of theory.