Investigation on the molecular, electronic and spectroscopic properties of rosmarinic acid: an intuition from an experimental and computational perspective

Various drugs such as corticosteroids, salbutamol, and β2 agonist are available for the treatment of asthma an inflammatory disease and its symptoms, although the ingredient and the mode of action of these drugs are not clearly elucidated. Hence this research aimed at carrying out improved scientific research with respect to the use of natural product rosmarinic acid which poses minima, side effects. Herein, we first carried out extraction, isolation, and spectroscopic (FT-IR, 1H-NMR and 13C-NMR) investigation, followed by molecular modeling analysis on the naturally occurring rosmarinic acid extracted from Rosmarinus officinalis. A detailed comparison of the experimental and theoretical vibrational analysis has been carried out using five DFT functionals: BHANDH, HSEH1PBE, M06-2X, MPW3PBE and THCTHHYB with the basis set 6-311++G (d, p) to investigate into the structural, reactivity, and stability of the isolated compound. Frontier molecular orbital analysis and appropriate quantum descriptors were calculated. Results showed that the compound was more stable at M06-2X and more reactive at HSEH1PBE with an energy gap of 6.43441 eV and 3.8047 eV, respectively, which was later affirmed by the global quantum reactivity parameters. From natural bond orbital analysis, π* → π* is the major contributor to electron transition with the summation perturbation energy of 889.57 kcal/mol, while π → π* had the perturbation energy totaling of 145.3 kcal/mol. Geometry analysis shows BHANDH to have lower bond length values and lesser deviation from 120° in carbon-carbon angle. The potency of the title molecule as an asthma drug was tested via a molecular docking approach and the binding score of -8.2 kcal/mol was observed against -7.0 of salbutamol standard drug, suggesting romarinic acid as a potential natural organic treatment for asthma.Communicated by Ramaswamy H. Sarma.

Yttrium- and zirconium-decorated Mg12O12-X (X = Y, Zr) nanoclusters as sensors for diazomethane (CH2N2) gas

Diazomethane (CH2N2) presents a notable hazard as a respiratory irritant, resulting in various adverse effects upon exposure. Consequently, there has been increasing concern in the field of environmental research to develop a sensor material that exhibits heightened sensitivity and conductivity for the detection and adsorption of this gas. Therefore, this study aims to provide a comprehensive analysis of the geometric structure of three systems: CH2N2@MgO (C1), CH2N2@YMgO (CY1), and CH2N2@ZrMgO (CZ1), in addition to pristine MgO nanocages. The investigation involves a theoretical analysis employing the DFT/ωB97XD method at the GenECP/6-311++G(d,p)/SDD level of theory. Notably, the examination of bond lengths within the MgO cage yielded specific values, including Mg15-O4 (1.896 Å), Mg19-O4 (1.952 Å), and Mg23-O4 (1.952 Å), thereby offering valuable insights into the structural properties and interactions with CH2N2 gas. Intriguingly, after the interaction, bond length variations were observed, with CH2N2@MgO exhibiting shorter bonds and CH2N2@YMgO showcasing longer bonds. Meanwhile, CH2N2@ZrMgO displayed shorter bonds, except for a longer bond in Mg19-O4, suggesting increased stability due to shorter bond distances. The study further investigated the electronic properties, revealing changes in the energy gap that influenced electrical conductivity and sensitivity. The energy gap increased for Zr@MgO, CH2N2@MgO, CH2N2@YMgO, and CH2N2@ZrMgO, indicating weak interactions on the MgO surface. Conversely, Y@MgO showed a decrease in energy, suggesting a strong interaction. The pure MgO surface exhibited the ability to donate and accept electrons, resulting in an energy gap of 4.799 eV. Surfaces decorated with yttrium and zirconium exhibited decreased energies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), as well as decreased energy gap, indicating increased conductivity and sensitivity. Notably, Zr@MgO had the highest energy gap before CH2N2 adsorption, but C1 exhibited a significantly higher energy gap after adsorption, implying increased conductivity and sensitivity. The study also examined the density of states, demonstrating significant variations in the electronic properties of MgO and its decorated surfaces due to CH2N2 adsorption. Moreover, various analysis techniques were employed, including natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), and noncovalent interaction (NCI) analysis, which provided insights into bonding, charge density, and intermolecular interactions. The findings contribute to a deeper understanding of the sensing mechanisms of CH2N2 gas on nanocage surfaces, shedding light on adsorption energy, conductivity, and recovery time. These results hold significance for gas-sensing applications and provide a basis for further exploration and development in this field.

Metals (Ga, In) decorated fullerenes as nanosensors for the adsorption of 2,2-dichlorovinyldimethylphosphate agrochemical based pollutant

Owing to the fact that the use of 2,2-dichlorovinyldimethylphosphate (DDVP) as an agrochemical has become a matter of concern due to its persistence and potential harm to the environment and human health. Detecting and addressing DDVP contamination is crucial to protect human health and mitigate ecological impacts. Hence, this study focuses on harnessing the properties of fullerene (C60) carbon materials, known for their biological activities and high importance, to develop an efficient sensor for DDVP. Additionally, the sensor's performance is enhanced by doping it with gallium (Ga) and indium (In) metals to investigate the sensing and trapping capabilities of DDVP molecules. The detection of DDVP is carefully examined using first-principles density functional theory (DFT) at the Def2svp/B3LYP-GD3(BJ) level of theory, specifically analyzing the adsorption of DDVP at the chlorine (Cl) and oxygen (O) sites. The adsorption energies at the Cl site were determined as - 57.894 kJ/mol, - 78.107 kJ/mol, and - 99.901 kJ/mol for Cl_DDVP@C60, Cl_DDVP@Ga@C60, and Cl_DDVP@In@C60 interactions, respectively. At the O site, the adsorption energies were found to be - 54.400 kJ/mol, - 114.060 kJ/mol, and - 114.056 kJ/mol for O_DDVP@C60, O_DDVP@Ga@C60, and O_DDVP@In@C60, respectively. The adsorption energy analysis highlights the chemisorption strength between the surfaces and the DDVP molecule at the Cl and O sites of adsorption, indicating that the O adsorption site exhibits higher adsorption energy, which is more favorable according to the thermodynamics analysis. Thermodynamic parameters (∆H and ∆G) obtained from this adsorption site suggest considerable stability and indicate a spontaneous reaction in the order O_DDVP@Ga@C60 > O_DDVP@In@C60 > O_DDVP@C60. These findings demonstrate that the metal-decorated surfaces adsorbed on the oxygen (O) site of the biomolecule offer high sensitivity for detecting the organophosphate molecule DDVP.

B- and Al-Doped Porous 2D Covalent Organic Frameworks as Nanocarriers for Biguanides and Metformin Drugs

Nanostructures such as nanosheets, nanotubes, nanocages, and fullerenes have been extensively studied as potential candidates in various fields since the advancement of nanoscience. Herein, the interaction between biguanides (BGN) and metformin (MET) on the modified covalent organic framework (COF), COF-B, and COF-Al was investigated using density functional theory at the ωB97XD/6-311+G (d, p) level of computation to explore a new drug delivery system. The electronic properties evaluation reveals that the studied surfaces are suited for the delivery of both drug molecules. The calculated adsorption energies and basis set superposition errors (BSSE) ranged between -21.20 and -65.86 kJ/mol. The negative values obtained are an indication of excellent interaction between the drug molecules and the COF surfaces. Moreover, BGN is better adsorbed on COF-B with E_ads of -65.86 kJ/mol, while MET is better adsorbed on COF-Al with E_ads = -47.30 kJ/mol. The analysis of the quantum theory of atom in molecules (QTAIM) explained the nature and strength of intermolecular interaction existing between the drug molecules BGN and MET with the adsorbing surfaces. The analysis of noncovalent interaction (NCI) shows a weak hydrogen-bond interaction. Other properties such as quantum chemical descriptors and natural bond orbital (NBO) analysis also agree with the potential of COF surfaces as drug delivery systems. The electron localization function (ELF) is discussed, and it confirms the transitions occurring in the NBO analysis of the complexes. In conclusion, COF-B and COF-Al are suitable candidates for the effective delivery of BGN and MET.

Detection of Carbon, Sulfur, and Nitrogen Dioxide Pollutants with a 2D Ca12O12 Nanostructured Material

In recent times, nanomaterials have been applied for the detection and sensing of toxic gases in the environment owing to their large surface-to-volume ratio and efficiency. CO₂ is a toxic gas that is associated with causing global warming, while SO₂ and NO₂ are also characterized as nonbenign gases in the sense that when inhaled, they increase the rate of respiratory infections. Therefore, there is an explicit reason to develop efficient nanosensors for monitoring and sensing of these gases in the environment. Herein, we performed quantum chemical simulation on a Ca₁₂O₁₂ nanocage as an efficient nanosensor for sensing and monitoring of these gases (CO₂, SO₂, NO₂) by employing high-level density functional theory modeling at the B3LYP-GD3(BJ)/6-311+G(d,p) level of theory. The results obtained from our studies revealed that the adsorption of CO₂ and SO₂ on the Ca₁₂O₁₂ nanocage with adsorption energies of -2.01 and -5.85 eV, respectively, is chemisorption in nature, while that of NO₂ possessing an adsorption energy of -0.69 eV is related to physisorption. Moreover, frontier molecular orbital (FMO), global reactivity descriptors, and noncovalent interaction (NCI) analysis revealed that the adsorption of CO₂ and SO₂ on the Ca₁₂O₁₂ nanocage is stable adsorption, while that of NO₂ is unstable adsorption. Thus, we can infer that the Ca₁₂O₁₂ nanocage is more efficient as a nanosensor in sensing CO₂ and SO₂ gases than in sensing NO₂ gas.

Synthesis, characterization, and theoretical investigation of 4-chloro-6(phenylamino)-1,3,5-triazin-2-yl)asmino-4-(2,4-dichlorophenyl)thiazol-5-yl-diazenyl)phenyl as potential SARS-CoV-2 agent

The synthesis of 4-chloro-6(phenylamino)-1,3,5-triazin-2-yl)amino-4-(2,4 dichlorophenyl)thiazol-5-yl-diazenyl)phenyl is reported in this work with a detailed structural and molecular docking study on two SARS-COV-2 proteins: 3TNT and 6LU7. The studied compound has been synthesized by the condensation of cyanuric chloride with aniline and characterized with various spectroscopic techniques. The experimentally obtained spectroscopic data has been compared with theoretical calculated results achieved using high-level density functional theory (DFT) method. Stability, nature of bonding, and reactivity of the studied compound was evaluated at DFT/B3LYP/6-31 + (d) level of theory. Hyper-conjugative interaction persisting within the molecules which accounts for the bio-activity of the compound was evaluated from natural bond orbital (NBO) analysis. Adsorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) properties of the experimentally synthesized compound was studied to evaluate the pharmacological as well as in silico molecular docking against SARS-CoV-2 receptors. The molecular docking result revealed that the investigated compound exhibited binding affinity of −9.3 and −8.8 for protein 3TNT and 6LU7 respectively. In conclusion, protein 3TNT with the best binding affinity for the ligand is the most suitable for treatment of SARS-CoV-2.