MEP Study Research Articles

Topological and DFT studies of 8-hydroxyquinoline derivative and its copper complex having supramolecular interactions network

Properties of single crystal depend on molecular architecture in the lattice which is related to its topology. The topology of the molecule come into existence due to its different non-covalent interactions. For this reason, Hirshfeld and molecular electrostatic potential analysis of the molecule help to understand the types and strength of non-covalent interactions. The topological analysis of [Cu(qmbn)(q)(Cl)] complex was investigated with the help of density functional theory, Hirshfeld and MEP study. In molecular packing, it showed 12,14-c net with 12,14 T5 topological type. For the overall structure, the subnet of 12,14-c underlying net (UN) with 1 M2-1topological type was observed. The hydrogen bonding, Cl-π, weak π…π and van der Waals interactions play important role to maintain the molecular topology.

Crystal structure, High-resolution X-ray diffraction and Hirshfeld surface analysis of a novel third-order nonlinear optical crystal: Diisopropylammonium oxalate

To quench the escalated demand of the photonic industry, substantial research has been focused on the development of new nonlinear optical materials. In the present work, we report the growth of novel Diisopropylammonium oxalate crystal, a potential candidate for third-order nonlinear optical properties. The titled crystal was subjected to a number of characterization methods to evaluate its structure and properties. The single crystal X-ray diffraction was employed to calculate the lattice parameters as a = 7.9151 Å, b = 9.7957 Å, c = 14.3528 Å, α=γ=90°, β= 103.851° The crystal belongs to the monoclinic space group P21/n. The high resolution X-ray diffraction demonstrates the crystalline quality, presence of dislocations, defects, grain boundaries, etc. of the grown single crystal. The 3D Hirshfeld surface analysis was utilized to illustrate the molecular interactions present inside the single crystal of Dipa-O. HOMO-LUMO analysis and MEP studies have been carried out at the DFT/B3LYP/6–311G(d, p) level of theory. Whereas, 1H and 13C Nuclear Magnetic Resonance studies were carried out on the crystal to discover the bonding and chemical environment within its molecule. For the assessment of optical properties, UV–Vis and Photoluminescence studies were conducted. The thermal analysis of the material was done through Thermal gravimetric/Differential thermal analysis studies which show that the crystal is stable up to 155 °C. The third harmonic generation behavior of the titled crystal was confirmed by Z-scan analysis. The nonlinear absorption coefficient is calculated as 4.10 × 10−12 cm/W and nonlinear refractive index as -1.11 × 10−17 cm2/W.

Multitarget Diallyl Disulfides (DADS) against Aβ Aggregation: Screening through Molecular Docking with Aβ42 & ZnII‐Aβ16, ADME, DFT & Synthetic Strategy

AbstractThe Aβ42 amyloid aggregation and its stabilization by coordination metals like ZnII through chelation, are the major pathological causes behind the occurrence of Alzheimer's disease (AD). Natural compounds like curcumin and chrysamine G have depicted Aβ42 aggregation inhibition, metal chelation and anti‐oxidant properties. Likewise garlic derived diallyl disulfide (DADS) has shown metal chelation, acetylcholinesterase (AChE) inhibition and antioxidant properties. In the present study a library of thirty four unnatural symmetrical DADS derivatives with aliphatic, aryl and new heteroaryl spacer groups, has been designed on the basis of electron releasing/withdrawing substituents and N/O heteroatom. The library was screened using various theoretical tools for their molecular properties and bioactivity with different receptors, to filter eleven potentially active derivatives. Further, Molecular docking study with Aβ42 (PDB ID: 1IYT) and ZnII‐Aβ16 (PDB ID: 1ZE9) displayed significant binding of heteroaryl DADS derivatives with highest binding energies and zinc binding ability. DFT calculations helped to predict their binding ability with free ZnII ion through disulfide linkage. MEP studies specified their reactive sites of binding. Finally, a synthetic protocol using less toxic reagents has been designed for their synthesis and an in vitro antioxidant activity has been evaluated.

Synthesis, Molecular Docking, MEP and SAR Analysis, ADME-Tox Predictions, and Antimicrobial Evaluation of Novel Mono- and Tetra-Alkylated Pyrazole and Triazole Ligands

Newly synthesized compounds of N-alkylated heterocyclic compounds were prepared by condensation of amine with alcohol which undergoes a reaction of SN2. These newly synthesized derivatives were characterized by spectral analysis. The objective is to prepare new potent nontoxic antimicrobial agents which are easy to synthesize and could be scaled up in pharmaceutical industries. Thirteen new heterocyclic compounds containing a pyrazole moiety were synthesized with good yields (29.79 to 99.6%) and were characterized by FTIR, 1H NMR, 13C NMR, and CG-MS techniques. The compounds were divided into two series—monoalkylated compounds (1–11) and tetra-alkylated compounds (12 and 13)—and then evaluated for their in vitro antifungal and antibacterial activities against several fungal and bacterial strains. None of the monoalkylated compounds had antibacterial or antifungal activity. However, the two tetra-alkylated pyrazole ligands displayed strong antibacterial potential. Moreover, compound 12 was more potent against all tested bacterial strains than compound 13. Interestingly, compounds 12 and 13 acted as weak antifungal agents against Saccharomyces cerevisiae. ADME-Tox studies suggested that compounds 12 and 13 exhibit better toxicity profiles than the commercial antibiotic streptomycin. MEP studies suggested that compounds 12 and 13 have the same charge locations but differ in their values which are due to the condensed geometry of compound 13 that make it more polarizable than compound 12. Of particular interest, these different MEPs were evident in ligand protein docking, suggesting that compound 12 has better affinity with MGL enzyme than compound 13. All these findings suggested that these novel compounds represent promising antibacterial lead compounds.

Spectroscopic and Theoretical Explorations on 6-Hydromethyl-4-Methoxy-4- Methoxytetrahydro-Pyran-2, 3, 5-Triol-A Biomolecule

The chemical compound 6-hydromethyl-4-methoxy-4- methoxytetrahydro-pyran-2, 3, 5-triol (C7H14O6), was derived from the ethanol extract of Senna auriculata flower via GC-MS. FT-IR and NMR characterization of the compound support covalent bonding information and degree of degeneracy, respectively. 3D molecular structure was optimized to enhance the accuracy of computations. MEP, NBO, HOMO-LUMO, and Mulliken charge distribution studies provide details like reactive sites, electron density dislocation, and molecular interactions, charge transfer within the molecule and frontier orbital energies, electron density on the individual atom, and these were computed using hybrid B3-LYP quantum level with 6-311++G(d, p) basis set. Thermodynamic properties such as heat capacity, entropy, enthalpy, and their relation with temperature changes for the title molecule were also analyzed using THERMO.PL software. Non-linear optical properties namely polarizability, first-order hyperpolarizability, and electronic dipole moment have also been computed at B3-LYP level with 6-311++G (d, p) basis set. Docking simulation was initiated on the title molecule using Autodock 4.2 software and found to be an excellent inhibitor of ALR2, an enzyme.

Synthesis, crystal structure, Hirshfeld surface analysis, MEP study and mol-ecular docking of N-{3-[(4-meth-oxy-phen-yl)carbamo-yl]phen-yl}-3-nitro-benzamide as a promising inhibitor of hfXa.

The title compound, C21H17N3O5, consists of three rings, A, B and C, linked by amide bonds with the benzene rings A and C being inclined to the mean plane of the central benzene ring B by 2.99 (18) and 4.57 (18)°, respectively. In the crystal, mol-ecules are linked via N-H⋯O and C-H⋯O hydrogen bonds, forming fused R 2 2(18), R 3 4(30), R 4 4(38) rings running along [0] and R 3 3(37) and R 3 3(15) rings along [001]. Hirshfeld analysis was undertaken to study the inter-molecular contacts in the crystal, showing that the most significant contacts are H⋯O/O⋯H (30.5%), H⋯C/C⋯H (28.2%) and H⋯H (29.0%). Two zones with positive (50.98 and 42.92 kcal mol-1) potentials and two zones with negative (-42.22 and -34.63 kcal mol-1) potentials promote the N-H⋯O inter-actions in the crystal. An evaluation of the mol-ecular coupling of the title compound and the protein with enzymatic properties known as human coagulation factor Xa (hfXa) showed the potential for coupling in three arrangements with a similar minimum binding energy, which differs by approximately 3 kcal mol-1 from the value for the mol-ecule Apixaban, which was used as a positive control inhibitor. This suggests the title compound exhibits inhibitory activity.

Spectroscopic, Electronic and Optical Properties of 4-Nitroimidazole using DFT Calculations

Theoretical and experimental vibrational spectra of 4-nitroimidazole were studied by FTIR, FT-Raman spectroscopic techniques and density functional theory (DFT) method. The contributions of the different modes to each wavenumber were confirmed using total energy distribution (TED). The optimized parameters and thermodynamic properties of 4-nitroimidazole have been computed. The charge transfer interactions of the molecule were explained from the small value of HOMO-LUMO energy gap. The NBO analysis, Mulliken’s plot and MEP studies of the molecule have also been reported.

Crystal structure and the DFT and MEP study of 4-benzyl-2-[2-(4-fluoro-phen-yl)-2-oxoeth-yl]-6-phenyl-pyridazin-3(2H)-one.

The title pyridazin-3(2H)-one derivative, C25H19FN2O2, crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In mol-ecule A, the 4-fluoro-phenyl ring, the benzyl ring and the phenyl ring are inclined to the central pyridazine ring by 86.54 (11), 3.70 (9) and 84.857 (13)°, respectively. In mol-ecule B, the corresponding dihedral angles are 86.80 (9), 10.47 (8) and 82.01 (10)°, respectively. In the crystal, the A mol-ecules are linked by pairs of C-H⋯F hydrogen bonds, forming inversion dimers with an R 2 2(28) ring motif. The dimers are linked by C-H⋯O hydrogen bonds and a C-H⋯π inter-action, forming columns stacking along the a-axis direction. The B mol-ecules are linked to each other in a similar manner and form columns separating the columns of A mol-ecules.

A novel synthesis of octahydropyrido[3,2-c]carbazole framework of aspidospermidine alkaloids and a combined computational, FT-IR, NMR, NBO, NLO, FMO, MEP study of the cis-4a-Ethyl-1-(2hydroxyethyl)-2,3,4,4a,5,6,7,11c-octahydro-1H-pyrido[3,2-c]carbazole

In this study, we performed a novel synthesis of the octahydropyrido[3,2-c]carbazole derivative 6 from 1 in five steps with a 34% overall yield. We also developed a unique compound 2 by a cyclization reaction from the cyanoethylation of compound 1, which is an intermediate step in the synthesis of Aspidospermidine. The parent compound of Aspidospermidine alkaloids, comprise a large family of diverse structures. As a result, we obtained octahydropyrido[3,2-c]carbazole (6)and the proposed method may be applicable to other alkaloids. All quantum chemical calculations of the cis-4a-Ethyl-1-(2-hydroxyethyl)-2,3,4,4a,5,6,7,11c-octahydro-1H-pyrido[3,2-c]carbazole have been performed with the DFT/B3LYP and HF methods by using the Gaussian 09W software package. The most stable conformer obtained from the Potential Energy Surface (PES) scan analysis at the B3LYP/6-31G** level of theory in the gas phase was used as the starting structure of the title compound to further computational analysis. The Natural Bond Orbital (NBO) and NLO analyses were performed to evaluate the intra-molecular interactions contributing to the molecular stability and to predict the optical properties of the title compound, respectively. Gauge-Independent Atomic Orbital (GIAO) approach was used to determine the 1H and 1C NMR chemical shifts of the title compound by subtracting the shielding constants of TMS at both methods. The calculated vibrational frequencies of the title compound were assigned by using the VEDA program and were scaled down by using the scaling factor 0.9668 for B3LYP/6-311++G(d, p) and 0.9050 for HF/6-311++G(d, p) to improve the calculated vibrational frequencies. The FMO (frontier molecular orbital) analysis was evaluated to predict the chemical and physical properties of the title compound and the HOMO, LUMO, and MEP diagrams were visualized by GaussView 4.1 program to present the reactive site of the title compound.

Non Linear Optical, Thermodynamic Analysis and Spectroscopic Investigation of GPA Optical Materials

In this work, density functional theory (DFT) calculations with B3LYP/6-311++G(d,p) basis sets was used to explore the electronic, structural, nonlinear optical and thermal properties aspects of glycine-phthalic acid (GPA) optical materials. Dipole moment, static polarizability and first hyperpolarizability analysis of the molecule have been performed. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. MEP study confirms GPA as an electron rich species and explains its electrophilic nature. MEP shows that this molecule has several possible sites for electrophilic/nucleophilic attack in which V(r) calculations provide insights into the order of preference. The low value of HOMO-LUMO energy gap reflects the high chemical reactivity, low chemical stability and hardness of GPA molecule. Thermodynamic properties of the title compound have been calculated at different temperatures and the results reveal that the standard heat capacities (Cp), standard entropies (S) and standard enthalpy (H) increase with rise in temperature. These results discussed in this study will upsurge the knowledge to design and synthesize new type nonlinear optical materials with exceptional chemical and physical properties.

Excitability of the motor cortex in patients with migraine changes with the time elapsed from the last attack

BackgroundMotor-evoked potentials (MEPs) produced by single-pulse transcranial magnetic stimulation (TMS) of the motor cortex can be an objective measure of cortical excitability. Previously, MEP thresholds were found to be normal, increased, or even reduced in patients with migraine. In the present study, we determined whether the level of cortical excitability changes with the time interval from the last migraine attack, thereby accounting for the inconsistencies in previous reports.MethodsTwenty-six patients with untreated migraine without aura (MO) underwent a MEP study between attacks. Their data were then compared to the MEP data collected from a group of 24 healthy volunteers (HVs). During the experiment, the TMS figure-of-eight coil was positioned over the left motor area. After identifying the resting motor threshold (RMT), we delivered 10 single TMS pulses (rate: 0.1 Hz, intensity: 120% of the RMT) and averaged the resulting MEP amplitudes.ResultsThe mean RMTs and MEP amplitudes were not significantly different between the MO and HV groups. In patients with MO, the RMTs were negatively correlated with the number of days elapsed since the last migraine attack (rho = -0.404, p = 0.04).ConclusionOur results suggest that the threshold for evoking MEPs is influenced by the proximity of an attack; specifically, the threshold is lower when a long time interval has passed after an attack, and is higher (within the range of normative values) when measured close to an attack. These dynamic RMT variations resemble those we reported previously for visual and somatosensory evoked potentials and may represent time-dependent plastic changes in brain excitability in relation to the migraine cycle.

4. The degree of motor cortex excitability in migraine depends on the days elapsed since the last attack

Here, we investigated whether level of cortical excitability changes with the distance from the last migraine attack could explain previous inconsistent results. Twenty-six patients with untreated migraine without aura (MO) underwent MEP study between attacks and were compared to a group of 24 healthy volunteers (HV). The TMS figure-of-eight coil was positioned over the left motor area. We first identified the resting motor threshold (RMT) and then amplitude of MEP was evaluated by delivering and averaging 10 single pulses of TMS using a stimulus intensity of 120% RMT at a rate of 0.1 Hz. Mean RMTs (54.2 in MO vs. 55.8 in HV) and MEP amplitudes (3057 microV in MO vs. 3675 microV in HV) were not significantly different between MO and HV. In MO, the RMT negatively correlated with days elapsed since the last migraine attack ( r = −0.426, p = 0.03), i.e. RMT was minimal at a long time interval after an attack while it was greater and within the range of normative values approaching to an attack. The dynamic RMT variations found here resemble those we have previously reported for visual and somatosensory evoked potentials, and may represent time-dependent plastic changes in brain excitability in relation with the migraine cycle.

Effects of substituents and charge on the RCHO⋯X–Y {X = Cl, Br, I; Y = –CF3, –CF2H, –CFH2, –CN, –CCH, –CCCN; R = –OH, –OCH3, –NH2, –O−} halogen-bonded complexes

Noncovalent interactions involving halogen bonding interactions, one of the emerging interactions due to its directionality, have been a subject of interest for various researchers, owing to its role played in construction of supramolecular structures and crystal engineering. In this article, the RCHO⋯X–Y {X = Cl, Br, I; Y = –CF3, –CF2H, –CFH2, –CN, –CCH, –CCCN; R = –OH, –OCH3, –NH2, –O−} halogen-bonded complexes have been investigated with aid of quantum chemical calculations at MP2/aug-cc-pVDZ(-PP) level. The geometrical, spectroscopic and energetic properties have been analyzed for these complexes with QTAIM, MEP and NBO analyses. For same RCHO molecule, the interaction energies increase in the order of O⋯Cl < O⋯Br < O⋯I and for the same X–Y; the trend is (HO)CHO < (CH3O)CHO < (H2N)CHO. The present article also compares the neutral complexes involving (HO)CHO, (CH3O)CHO and (H2N)CHO carbonyl molecules with those of charged carbonyl species HCOO−. It has been found that strength of the latter complexes is highest among all of the four. The role of substituents in the complex formation has been analyzed on the basis of results obtained from MEP, QTAIM and NBO studies.

Molecular structure investigation and tautomerism aspects of (E)-3-benzylideneindolin-2-one

The synthesis and spectral characterization of the (E)-3-benzylideneindolin-2-one is reported. The compound crystallized in the monoclinic system with space group P21/n with cell coordinates a= 3.9849 (2) Å, b= 22.2236 (9) Å, c= 12.2501 (5) Å, β= 95.0535 (12) ∘, V=1080.64 (8) Å 3, and Z= 4. In the crystal, molecules are packed in chains formed via weak intermolecular C13–H13A ⋯O1 and N1-H1N1 …O1 hydrogen bonding. The relative stabilities of the two tautomeric isomers of 3 are calculated by DFT/B3LYP method using 6-311G(d,p) basis set in gas phase and in solution. The quantum chemical calculations, NMR studies and the XRD analyses showed that the keto form T0 is the only form that could exist in gas, solution and solid phases respectively. The calculated geometric parameters of the dimer molecule showed better agreement with the XRD data than those obtained for single isolated molecule. This shed light on the effect of intermolecular interactions on the calculated geometric parameters. MEP study showed that, the O-atom and the NH proton are the most reactive H-acceptor and H-donor sites, respectively. The N-H...O H-bonding interactions increased the negative charge at the O-atoms and the positive charge of the NH protons compared to the monomer unit. The synthesis, X-ray single crystal structure, spectral characterizations and DFT computation of the (E)-3-benzylideneindolin-2-one 3 is reported.

Molecular structure, FT-IR, FT-Raman, NBO, HOMO and LUMO, MEP, NLO and molecular docking study of 2-[(E)-2-(2-bromophenyl)ethenyl]quinoline-6-carboxylic acid

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of 2-[(E)-2-(2-bromophenyl)ethenyl]quinoline-6-carboxylic acid have been investigated experimentally and theoretically using Gaussian09 software package. Potential energy distribution of the normal modes of vibrations was done using GAR2PED program. 1H NMR chemical shifts calculations were carried out by using B3LYP functional with SDD basis set. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. MEP was performed by the DFT method and the predicted infrared intensities and Raman activities have also been reported. The calculated geometrical parameters are in agreement with that of similar derivatives. The title compound forms a stable complex with PknB as is evident from the binding affinity values and the molecular docking results suggest that the compound might exhibit inhibitory activity against PknB and this may result in development of new anti-tuberculostic agents.

Vibrational spectra, HOMO, LUMO, NBO, MEP analysis and molecular docking study of 2,2-diphenyl-4-(piperidin-1-yl)butanamide

The Fourier-Transform Infrared and Fourier-Transform Raman spectra of 2,2-diphenyl-4-(piperidin-1-yl)butanamide were recorded in the region 4000–400cm−1 and 4000–0cm−1. The vibrational wavenumbers are computed using HF and DFT methods. The complete vibrational assignments were performed on the basis of potential energy distribution using GAR2PED program. The geometrical parameters of the title compound are in agreement with the XRD data. From the MEP study, the negative electrostatic potential regions are mainly localized of carbonyl group and are possible sites for electrophilic attack and the positive regions are localized all the rings, indicating possible sites for nucleophilic attack. Stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using natural bond orbital analysis. The calculated HOMO and LUMO energies also confirm that charge transfer occurs within the molecule. PASS analysis of the title compound predicts among other activities, antidyskinetic activity. Molecular docking results draw us to the conclusion that the compound might exhibit inhibitory activity against adenosine A2A and may act as antidyskinetic agent.

Evoked potentials and disability in multiple sclerosis: A different perspective to a neglected method

Evoked potentials and disability in multiple sclerosis: a different perspective to a neglected method. ObjectiveBecause evoked potentials (EP) are reflections of the functional integrity of sensory-motor systems, they are expected to reflect the abnormality in patients with disabilities and handicaps and also be in correlation with scales. This assumption was tested. MethodsPatients with multiple sclerosis (MS) and myelopathy (M) and normal controls were investigated by EP, Multiple Sclerosis Walking Scale-12, timed 25-foot walk test and extended disability status scale (EDSS). EP results were converted to ordinal values, and correlations of these values with scales were calculated. Sensitivity and specificity analysis of EP parameters was also performed. ResultsTotal EP scores revealed high rates of abnormality in both groups, but MS revealed a different correlation pattern from M. The SEP+MEP summed score showed high sensitivity and specificity for MS and this was also correlated with the MS-related disability-ambulation scales including EDSS. The most specific parameter was the minimum M latency in the MEP study. ConclusionsFour extremity recordings of EP with the use of more parameters than usual and ordinal expression of results seem to be benefical in MS. Although this study was cross sectional in nature, results indicated that EP might be useful in clinical follow up.

Conformational analysis, X-ray crystallographic, FT-IR, FT-Raman, DFT, MEP and molecular docking studies on 1-(1-(3-methoxyphenyl) ethylidene) thiosemicarbazide

Conformational analysis, X-ray crystallographic, FT-IR, FT-Raman, DFT, MEP and molecular docking studies on 1-(1-(3-methoxyphenyl) ethylidene) thiosemicarbazide (MPET) are investigated. From conformational analysis the examination of the positions of a molecule taken and the energy changes is observed. The docking studies of the ligand MPET with target protein showed that this is a good molecule which docks well with target related to HMG-CoA. Hence MPET can be considered for developing into a potent anti-cholesterol drug. MEP assists in optimization of electrostatic interactions between the protein and the ligand. The MEP surface displays the molecular shape, size and electrostatic potential values. The optimized geometry of the compound was calculated from the DFT–B3LYP gradient calculations employing 6-31G (d, p) basis set and calculated vibrational frequencies are evaluated via comparison with experimental values.

Molecular structure, FT-IR, vibrational assignments, HOMO–LUMO, MEP, NBO analysis and molecular docking study of ethyl-6-(4-chlorophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of ethyl-6-(4-chlorophenyl)-4-(4-fluoro-phenyl)-2-oxocyclohex-3-ene-1-carboxylate have been investigated experimentally and theoretically using Gaussian09 software. The title compound was optimized using the HF and DFT levels of theory. The geometrical parameters are in agreement with the XRD data. The stability of the molecule has been analyzed by NBO analysis. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. Molecular electrostatic potential was performed by the DFT method. As can be seen from the MEP map of the title compound, regions having the negative potential are over the electro negative atoms, the region having the positive potential are over the phenyl rings and the remaining species are surrounded by zero potential. First hyperpolarizability is calculated in order to find its role in non linear optics. The title compound binds at the active sites of both CypD and β-secretase and the molecular docking results draw the conclusion that the compound might exhibit β-secretase inhibitory activity which could be utilized for development of new anti-alzheimeric drugs with mild CypD inhibitory activity.

Synthesis, molecular structure investigations and antimicrobial activity of 2-thioxothiazolidin-4-one derivatives

A variety of 2-thioxothiazolidin-4-one derivatives were prepared and their in vitro antimicrobial activities were studied. Most of these compounds showed significant antibacterial activity specifically against Gram-positive bacteria, among which compounds 4a,e,g, 5b,e,g,h and 6f exhibit high levels of antimicrobial activity against Bacillus subtilis ATCC 10400 with Minimum Inhibitory Concentration (MIC) value of 16μg/mL. All compounds have antifungal activity against Candida albicans. Unfortunately, however, none of the compounds were active against Gram-negative bacteria. The chemical structure of 3 was confirmed by X-ray single crystal diffraction technique. DFT calculations of 3 have been performed on the free C10H7Cl2NO2S2, 3a and the H-bonded complex, C10H7Cl2NO2S2·H2O, 3b to explore the effect of the H-bonding interactions on the geometric and electronic properties of the studied systems. A small increase in bond length was observed in the C12–O6 due to the H-bonding interactions between 3a and water molecule. MEP study has been used to recognize the most reactive sites towards electrophilic and nucleophilic attacks as well as the possible sites for the H-bonding interactions. The TD-DFT calculations have been used to predict theoretically the electronic spectra of the studied compound. The most intense transition band is predicted at 283.9nm due to the HOMO-2/HOMO-1 to LUMO transitions. NBO analyses were carried out to investigate the stabilization energy of the various intramolecular charge transfer interactions within the studied molecules.