Intermolecular Research Articles

Learning QM/MM potential using equivariant multiscale model.

The machine learning (ML) method emerges as an efficient and precise surrogate model for high-level electronic structure theory. Its application has been limited to closed chemical systems without considering external potentials from the surrounding environment. To address this limitation and incorporate the influence of external potentials, polarization effects, and long-range interactions between a chemical system and its environment, the first two terms of the Taylor expansion of an electrostatic operator have been used as extra input to the existing ML model to represent the electrostatic environments. However, high-order electrostatic interaction is often essential to account for external potentials from the environment. The existing models based only on invariant features cannot capture significant distribution patterns of the external potentials. Here, we propose a novel ML model that includes high-order terms of the Taylor expansion of an electrostatic operator and uses an equivariant model, which can generate a high-order tensor covariant with rotations as a base model. Therefore, we can use the multipole-expansion equation to derive a useful representation by accounting for polarization and intermolecular interaction. Moreover, to deal with long-range interactions, we follow the same strategy adopted to derive long-range interactions between a target system and its environment media. Our model achieves higher prediction accuracy and transferability among various environment media with these modifications.

Surface Passivation with Tailoring Organic Potassium Salt for Efficient FAPbI3 Perovskite Solar Cells and Modules

AbstractPassivating surface defects on perovskite films with tailored functional materials has emerged as one of the most effective strategies for achieving high‐performance perovskite solar cells (PSCs). Among existing material selections, potassium salts stand out for their effective passivation of defects surrounding perovskite grain boundaries. However, the widely used potassium salts are inorganic and only soluble in highly polar solvents, which limits their practical application for surface passivation. Herein, a novel organic potassium salt (KCFSO), with multiple organic functional groups and good solubility in low polar isopropanol, is reported to function as a post‐treatment agent for perovskite. Combined with experimental results and theoretical calculations, the formed multiple intermolecular interactions between KCFSO and perovskite are revealed to play a vital role in determining the defect passivation effect. Thus, the KCFSO‐modified film shows a more uniform surface potential distribution, dramatically decreased defect density, and improved charge transfer, leading to a champion power conversion efficiency (PCE) of 25.11%, and good stability for the derived PSCs. As a demonstration of scalability, the centimeter‐sized PSCs and 5 cm × 5 cm mini‐modules also demonstrate impressive PCEs of 24.17% and 20.18%, respectively. These findings provide insights into passivator design principles to achieve efficient and stable perovskite photovoltaics.

Ethane under pressure revisited using x-ray diffraction, Raman spectroscopy, infrared absorption, and abinitio calculations up to 150 GPa.

Ethane (C2H6) is anticipated to be the most stable compound within the carbon-hydrogen system under the 100GPa pressure range. Nevertheless, the properties of ethane under pressure are still poorly documented. Here, we present a comprehensive study of the structural and vibrational properties of C2H6 in a diamond anvil cell at pressures up to 150GPa. To obtain detailed data, ethane single-crystal was grown in a helium pressure-transmitting medium. Utilizing single-crystal x-ray diffraction, the distortion mechanism between the tetragonal and monoclinic phases, occurring over the 3.2-5.2GPa pressure range, is disclosed. Subsequently, no phase transition is observed up to 150GPa. The accurately measured compression curve is compared to various computational approximations. The vibrational modes measured by Raman spectroscopy and infrared absorption are well identified, and their evolution is well reproduced by abinitio calculations. In particular, an unusual anticrossing phenomenon occurs near 40GPa between a rocking and a stretching mode, likely attributable to intermolecular interactions through hydrogen bonding.

Selective Binding of Tannic Acid-Conjugated Lipid Nanovesicles to Proline-Rich Proteins Enhances Transdermal Lipophilic-Antioxidant Delivery.

Tannic acid (TA) possesses a notable ability to adhere to proline-rich proteins that make up skin cells and the extracellular matrix (ECM) in the skin tissue. Drug carriers with this specific adhesion ability exhibit improved drug delivery efficiency on the skin. Taking advantage of this, this study presents skin-adhesive TA-conjugated lipid nanovesicles (TANVs) for enhanced transdermal antioxidant delivery. We found that TANVs exhibited selective intermolecular interactions with keratinocyte proline-rich proteins (KPRPs) and collagen that makes up skin cells by hydrogen bonding and van der Waals interactions, further enabling the strong bonding to macroscopic skin itself and ECM. We used vitamin E (α-tocopherol), which is known to effectively reduce oxidative stress but has limited skin penetration, as a drug to verify improved in vitro delivery and therapeutic efficacy. The evaluation revealed that the antioxidant-loaded TANVs exerted excellent scavenging effects against reactive oxygen species induced by ultraviolet light or peroxides in the skin, thereby enabling the development of an active drug delivery system for dermal therapy.

Antibacterial and cytotoxicity studies of pyrrolo-based organic scaffolds and their binding interaction with bovine serum albumin.

Two pyrrolo-based compounds, 1H-pyrrolo[3,2-b]pyridine-3-carboxylic acid (L1) and 1H-pyrrolo[3,2-c]pyridine-4-carboxylic acid (L2), were employed for the detection of bovine serum albumin (BSA) by UV-Vis and fluorescence spectroscopic methods in phosphate buffer solution (pH = 7). In the presence of L1 and L2, the fluorescence emission of BSA at 340 nm was quenched and concomitantly a red-shifted emission band appeared at 420 nm (L1)/450 nm (L2). The fluorescence spectral changes indicate the protein-ligand complex formation between BSA and L1/L2. An isothermal titration calorimetry (ITC) experiment was conducted to determine the binding ability between BSA and L1/L2. The binding constants are found to be 4.45 ± 0.22 × 104 M-1 for L1 and 2.29 ± 0.11 × 104 M-1 for L2, respectively. The thermodynamic parameters were calculated from ITC measurements (i.e. ∆rH = -40 ± 2 kcal/mol, ∆rG = -4.57 ± 0.22 kcal/mol and -T∆rS = 35.4 ± 1.77 kcal/mol), which indicated that the protein-ligand complex formation between L1/L2 with BSA is mainly due to the electrostatic interactions. The protein-ligand interactions were studied by performing molecular docking. Further, the antibacterial assay of L1 and L2 was conducted against gram-positive and gram-negative bacterial strains in an effort to address the difficulties caused by the co-occurrence of antimicrobial and multidrug-resistant bacteria. E. coli and S. aureus were significantly inhibited by L1 and L2. The L1 exhibits 13, 12 and 15 mm, whereas L2 exhibits a 2, 3 and 5 mm zone of inhibition against S. aureus, S. pyogenesand E. coli, respectively. In silico molecular docking of L1 and L2 was performed with bacterial DNA gyrase to establish the intermolecular interactions. Finally, the in vitro cytotoxicity activities of the ligands L1 and L2 have been carried out using drosophila.

Experimental and theoretical study of novel polyamine bis(nitrophenylureylbenzamide) receptors with anion and cation interaction capacity

In this work the interaction of three new heterotopic polyamine bis(nitrophenylureylbenzamide) receptors (R = 3A-3C) with anions (A) and cations (M) was analyzed by UV–Vis spectroscopy and theoretical calculations. These receptors are highly pre-organized and form supramolecular complexes R-A at different ratios depending on the anion characteristics (1:1, 2:1, 3:1 and 4:3). The calculated log K values based on UV–Vis absorbance profiles and the structural information obtained from geometry optimizations using Density Functional Theory indicate strong stability in these complexes due to multiple intermolecular interactions between both species. Changes in the absorption band of receptors evidence the interaction with metallic ions forming complexes R-M (1:1) and the theoretical calculations predict the coordination with polyamine and amide groups adopting an aza-crown type conformation surrounding the Cu or Zn atoms. The subsequent formation of ternary complexes R-M-A with acetate showed different spectral changes for R-Cu and R-Zn ligands. The spectral changes with R-Cu ligands allowed to identified and calculated log K values for R-Cu-A and R-Cu-A2 complexes. Moreover, the optimized structures for R-Cu-A and R-Cu-A2 complexes show the coordination of one acetate ion with the metal center and a subsequent interaction of a second acetate with the urea groups in agreement with the experimental results.

Color Polymorphism and Room Temperature Phosphorescence of 4-bromo-2,7-di-tert-butyl-9-methoxypyrene.

The title compound has two polymorphic crystal structures having strikingly different absorption and luminescence spectra that result from different packing motifs in the crystal lattice. The polymorph with brick wall-like packing of molecules is white and shows very weak violet fluorescence whereas the second polymorph, where molecules are arranged in columnar stacks, is bright yellow and displays intense green fluorescence with maximum at 487 nm (20530 cm-1). In the white polymorph, where the distance between neighboring chromophores is increased, absorption and fluorescence spectra are similar to those of monomer in solution, and intersystem crossing to triplet manifold is the dominant pathway of relaxation. In the yellow polymorph, molecules within the columnar stacks are rotated which mitigates the steric hindrance and leads to closer π-stacking of the pyrene cores. That increases the ππ overlap and strengthens intermolecular interactions decreasing energy of the excited states. This affects emission spectra and photophysical processes - fluorescence yield grows whereas triplet formation yield decreases when S1 is lowered below higher triplet states and conditions for effective vibronic spin-orbit coupling are not favorable. The effect is not observed for other similar pyrene derivatives, testifying the uniqueness of the phenomenon.

Ab Initio Characterization of the CO2-Water Interface Using Unsupervised Machine Learning for Dimensionality Reduction.

Precise characterization of the supercritical CO2-water interface under high pressure and temperature conditions is crucial for the geological storage of carbon dioxide (CO2) in deep saline aquifers. Molecular dynamics (MD) simulations offer a valuable approach to gaining insight into the CO2-water interface at a microscopic level. However, no attempt has been made to characterize the CO2-water interface with the accuracy afforded by ab initio calculations. In this study, we performed ab initio MD (AIMD) simulations to investigate the structural and dynamical properties of the CO2-water interface, comparing the results with those obtained from classical force-field MD (FF-MD) simulations. Molecular orientation at the interface was well reproduced in both AIMD and FF-MD simulations. Characteristic structural fluctuations of water at the interface were unveiled by applying multidimensional scaling and time-dependent principal component analysis to the AIMD trajectories; however, they were not prominent in the FF-MD simulations. Furthermore, our study demonstrated a marked difference in the residence time of molecules in the interface region between AIMD and FF-MD simulations, indicating that time-dependent properties of the CO2-water interface strongly depend on the description of the intermolecular forces.

The dissolution behavior of 3,4-O-isopropylidene clindamycin in twelve mono-solvents: Solubility, intermolecular interactions, and apparent thermodynamics

The solubility of 3, 4-O-isopropylidene clindamycin (OIC) was determined in twelve solvents at p = 101.3 kPa with the temperature from 273.15 K to 313.15 K. The solubility of OIC increases with the raise temperature. Among the selected solvents, 2-butanol showed the best dissolving ability for OIC, while acetonitrile showed the worst dissolving ability. The obtained data are neatly correlated with five models, including van't Hoff, Yaws, λh, Wilson, and nonrandom two-liquid interaction model (NRTL), with Yaws equation yielding the most accurate predicted results. Moreover, the Conductor-like Screening Model for Real solvents (COSMO-RS) provides better calculated results for the protic solvents than the aprotic ones except for acetonitrile. The dissolving mechanism of OIC was investigated with intermolecular interaction between OIC and solvents, and the analyses indicate that the dissolving process is affected by intermolecular interaction, molecular shape, and size of both solvents and the solute. The apparent thermodynamics analysis shows that the dissolving process of OIC before reaching equilibrium in the twelve solvents is spontaneous, endothermic, and enthalpy driven.

Measurements of Nuclear Magnetic Shielding in Molecules.

The origin of nuclear magnetic shielding in diamagnetic molecules is discussed, pointing out various contributions to the shielding from electrons and the effects of intra- and intermolecular interactions. In NMR practice, chemical shifts are determined first as the measure of shielding in observed samples. The descriptions of shielding and chemical shifts are not fully consistent. Gas phase studies permit the withdrawal of intermolecular contributions from shielding and obtaining the magnetic shielding data in isolated molecules. The shielding determination in molecules is possible using at least three methods delivering the reference shielding standards for selected nuclei. The known shielding of one magnetic nucleus can be transferred to other nuclei if the appropriate nuclear magnetic moments are available with satisfactory accuracy. It is possible to determine the nuclear magnetic dipole moments using the most advanced ab initio shielding calculations jointly with the NMR frequencies measurements for small-sized isolated molecules. Helium-3 gas is postulated as all the molecules' primary and universal reference standard of shielding. It can be easily applied using common deuterium lock solvents as the secondary reference standards. The measurements of absolute shielding are available for everyone with the use of standard NMR spectrometers.

The supramolecular synthon behavior within cocrystals of pyrazinamide and alkyl dicarboxylic acids: a perspective from terahertz spectroscopy and quantum chemical calculation

The supramolecular synthon behavior within cocrystals of pyrazinamide and alkyl dicarboxylic acids: a perspective from terahertz spectroscopy and quantum chemical calculation

Effect of cellulose nanofibrils on formation, interactions and gelation properties of chickpea protein isolate emulsion gels

Chickpea protein isolate (CPI) emulsion gels suffered from poor elasticity and loose structure, which greatly limited their application and development. This work aimed to investigate the effect of cellulose nanofibrils (CNFs) on the intermolecular interactions, protein structure, gel properties, and microstructure of CPI emulsion gels. Results showed that CNFs enhanced the hydrophobic interactions, electrostatic interactions, and hydrogen bonding of the CPI emulsion gels, and contributed to the transition of the secondary structure of CPI from α-helix to β-sheet structure. CPI-CNFs emulsion gels exhibit better textural properties, rheological properties and water holding capacity compared to CPI emulsion gels. Gel strength increased from 40.67 g to 56.26 g and hardness increased from 42.95 g to 60.67 g. Furthermore, scanning electron microscopy showed that the CPI emulsion gel structures were transformed from rough and porous to uniform and dense with the addition of CNFs. This study indicated that CNFs will help improve the properties of CPI emulsion gels with wide applications in the food field.

Effect of surfactant modified phosphogypsum whisker on service performance of asphalt based on multi-scale experiments

The development of modern chemical technology had inevitably produced massive phosphogypsum (PSP), the accumulation and storage of PSP had caused serious economic losses and environmental pollution. As the secondary refining product of PSP, the application of phosphogypsum whisker (PSW) to asphalt pavement not only effectively mitigated the adverse impact of PSP on the economy and environment, but also promoted the resourceful utilization of solid waste. However, since PSW was an inorganic material, it was difficult to fuse well with asphalt. Therefore, to enhance the compatibility of PSW with asphalt, this study investigated the modification process of PSW by using four surfactants to modify PSW with organic coating. The effect of surfactants on the surface activity of PSW was evaluated by relevant tests, and the surface enhancement modification mechanism and microstructure of surfactants on PSW were investigated, and then the effect of surfactant-modified PSW (MPSW) on the service performance of asphalt was evaluated. The results showed that the surfactant covered the surface of PSW by intermolecular forces and chemical bonding, which enhanced the surface activity of PSW. The compatibility of PSW with asphalt was enhanced by surfactant, and the MPSW 10599was just physically blended with virgin asphalt. Although the brittleness of virgin asphalt was enhanced to a certain degree by MPSW, the thermophysical properties of virgin asphalt at low temperature was significantly improved, and the incorporation of MPSW enhanced the thermal stability and flame retardancy of virgin asphalt. The incorporation of MPSW would slightly increase the viscosity of virgin asphalt, but the viscous activation energy was reduced and the temperature sensitivity was improved. Furthermore, the low temperature performance of virgin asphalt was improved to a certain degree with the incorporation of MPSW, while the improvement effect was not significant once the temperature was close to the glass transition temperature. Finally, combined with the relevant test results, the recommended dosage of MPSW in asphalt was 10% in this study, and the surface modification of PSW by surfactant was a multifunctional method of powder modification.

The impact of copper nanoparticles surfactant on the structural and biological properties of chitosan/sodium alginate wound dressings

Multifunctional wound dressings based on hydrogels are an efficacious and practicable strategy in therapeutic processes and accelerated chronic wound healing. Here, copper (Cu) nanoparticles were added to chitosan/sodium alginate (CS/SA) hydrogels to improve the antibacterial properties of the prepared wound dressings. Due to the super-hydrophobicity of Cu nanoparticles, polyethylene glycol (PEG) was used as a surfactant, and then added to the CS/SA-based hydrogels. The CS/SA/Cu hydrogels were synthesized with 0, 2, 3.5, and 5 wt% Cu nanoparticles. The structural and morphological properties in presence of PEG were evaluated using Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and field emission scanning electron microscopy (FESEM). The biodegradation and swelling properties of the hydrogels were investigated in phosphate buffer saline (PBS) at 37 °C for up to 30 days. Cell viability and adhesion, as well as antibacterial behavior, were investigated via MTT assay, FESEM, and disk diffusion method, respectively. The obtained results showed that PEG provided new intra- and intermolecular bonds that affected significantly the hydrogels' degradation and swelling ratio, which increased up to ~1200 %. Cell viability reached ~110 % and all samples showed remarkable antibacterial behavior when CS/SA/Cu containing 2 wt% was introduced. This study provided new insights regarding the use of PEG as a surfactant for Cu nanoparticles in CS/SA hydrogel wound dressing, ultimately affecting the chemical bonding and various properties of the prepared hydrogels.

Exploring the structural, photophysical, and electrical properties of Dopant-Free Hole Transporting Material based on 2, 7-carbazole from experimental to simulation

This paper presents the development of a dopant-free HTM as a thin film, utilizing carbazole (2,7) as a central building block. The deposition of homogeneous thin films of HTM2 was successfully achieved through Physical Vapor Deposition. The morphological, optical, and electrical properties of the fabricated samples were extensively studied using techniques such as Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), UV-visible spectroscopy, and Photoluminescence Technique. The AFM and SEM analyses demonstrated the uniformity and flatness of the thin film surfaces. The UV spectra results indicated that the maximum absorption spectra did not exhibit significant shifts when measured in chlorobenzene solvent, with an estimated band gap of approximately 2.96 eV. Photoluminescence spectroscopy and decay time measurements were conducted on HTM2 thin films, which revealed emission in the green-yellow region. The photoluminescence spectra of the thin films exhibited red-shifted emission bands compared to the solution, attributable to stronger π-π intermolecular interactions resulting in the closeness of the molecules in the solid state. This work finally couples the theoretical and experimental results to validate our obtained results and to get an idea about the efficiency of the cell-based HTM2. The obtained results confirmed that the investigated material can find applications in perovskite solar cells.

Investigation on molecular and biomolecular spectroscopy of the novel 2BCA molecule to analyse its biological activities and binding interaction with nipah viral protein

The molecule of 2-Biphenyl Carboxylic Acid (2BCA), which contains peculiar features, was explored making use of density functional theory (DFT) and experimental approaches in the area of quantum computational research. The optimised structure, atomic charges, vibrational frequencies, electrical properties, electrostatic potential surface (ESP), natural bond orbital analysis and potential energy surface (PES) were obtained applying the B3LYP approach with the 6–311++ G (d,p) basis set.. The 2BCA molecule was examined for possible conformers using a PES scan. The methods applied for spectral analyses included FT-IR, FT-RAMAN, NMR, and UV–Vis results. Vibrational frequencies for all typical modes of vibration were found using the Potential Energy Distribution (PED) data. The UV–Vis spectrum was simulated using the TD-DFT technique, which is also seen empirically. The Gauge-Invariant Atomic Orbital (GIAO) approach was employed to model and study the 13C and 1H NMR spectra of the 2BCA molecule in a CDCL3 solution. The spectra were then exploited experimentally to establish their chemical shifts. To predict the donor and acceptor interaction, the NBO analysis was used. The electrostatic potential surface was employed to anticipate the locations of nucleophilic and electrophilic sites. Hirshfeld surfaces and their related fingerprint plots are exploited for the investigation of intermolecular interactions. Reduced Density Gradient (RDG) helps to measure and illustrate electron correlation effects, offering precise insights into chemical bonding, reactivity, and the electronic structure of 2BCA. According to Lipinski and Veber’s drug similarity criteria, 2BCA exhibits the typical physicochemical and pharmacokinetic properties that make it a potential oral pharmaceutical candidate. According to the findings of a molecular docking study, the 2BCA molecule has promise as a treatment agent for the Nipah virus (PDB ID: 6 EB9), which causes severe respiratory and neurological symptoms in humans.

Sequentially photocatalytic degradation of mussel-inspired polydopamine: From nanoscale disassembly to effective mineralization

Mussel-inspired polydopamine (PDA) coating has been utilized extensively as versatile deposition strategies that can functionalize surfaces of virtually all substrates. However, the strong adhesion, stability and intermolecular interaction of PDA make it inefficient in certain applications. Herein, a green and efficient photocatalytic method was reported to remove adhesion and degrade PDA by using TiO2-H2O2 as photocatalyst. The photodegradation process of the PDA spheres was first undergone nanoscale disassembly to form soluble PDA oligomers or well-dispersed nanoparticles. Most of the disassembled PDA can be photodegraded and finally mineralized to CO2 and H2O. Various PDA coated templates and PDA hollow structures can be photodegraded by this strategy. Such process provides a practical strategy for constructing the patterned and gradient surfaces by the “top-down” method under the control of light scope and intensity. This sequential degradation strategy is beneficial to achieve the decomposition of highly crosslinked polymers.

Wetting and aggregation mechanisms of coal molecules via XTG and SDBS based on molecular simulation

To study the interaction process of sodium dodecyl benzene sulfonate (SDBS) and xanthan gum (XTG) molecules in a composite dust suppressant and its influence mechanisms on the wettability and agglomeration characteristics of bituminous coal dust, material studio software was used to establish water–XTG binary system models, water–SDBS–XTG ternary system models, and water–SDBS–XTG–coal quaternary system models. Then, molecular dynamics simulations were performed through angular distribution, relative concentration distribution, mean squared displacement (MSD), and interaction energy to study the interaction mechanism between SDBS and XTG and the change in wettability of coal dust. Results showed that the configuration in the binary system changed after stabilization, and SDBS transformed from a disordered state into a directional arrangement with the head group oriented toward the liquid phase and the tail group oriented toward the gas phase. In the ternary system, the head group of SDBS interacted with the XTG molecules, and the XTG wound into a helical structure, reducing the viscosity of the solution. With an increase in the number of SDBS molecules, the angle of the head group of SDBS and the tail chain of SDBS increased to 113.95°. The number of H bonds in the system increased from 1676 to 1697. In the quaternary system, the slope of the MSD curve increased with an increase in the number of SDBS molecules, and the diffusion coefficient increased from 0.36 × 10−5 cm2/s to 0.42 × 10−5 cm2/s with an enhancement of water wettability. The absolute value of the interaction energy increased from 5920.48 kJ/mol to 9295.35 kJ/mol. The higher the concentration of SDBS, the better the adsorption effect, and the more stable the molecular configuration. The number of H bonds and the distribution area of the overlapping region between water and coal gradually increased, indicating that the larger the area where water molecules could penetrate into the coal molecules, the better the wetting effect on coal. This study reveals the intermolecular interaction process and the mechanisms of coal dust wetting and agglomeration in a composite dust suppressant. It provides theoretical support for the application of this composite dust suppressant.

Novel series of hydrazones carrying pyrazole and triazole moiety: Synthesis, structural elucidation, quantum computational studies and antiviral activity against SARS-Cov-2

The novel series of hydrazones carrying both pyrazole and triazole moiety were synthesized and characterized using single crystal X-ray diffraction studies. It is found that the compound crystallizes in the triclinic system in the space group P1̅. Hirshfeld analysis was carried out to visualize the noncovalent intermolecular interactions which are responsible for molecular packing in the crystal. Further, density functional theory (DFT) calculations were used to calculate optimized molecular structure, stability, and a few of the quantum chemical parameters. Derived results are in good agreement with the experimentally obtained results. Analysis of frontier molecular orbitals (HOMO and LUMO) and their energy gap of the optimized structure revealed that the compound is stable in the gaseous state. Molecular electron densities, and electrostatic potential maps provide the reactive site and charge distribution of triazole group. Quantum theory of atoms in molecules (QTAIM) and reduced density gradient (RDG) analysis were carried out to explore the weak interactions present in the molecule. In addition, the synthesized compound was investigated as an inhibitor for SARS CoV-2 protease using in-silico molecular docking analysis to understand the mode of binding. The docking results showed the good binding score with Mpro protease 6LU7. Further, molecular dynamics (MD) were carried out for the best hit docked complexes.

Synthesis and X-ray characterization of two new 1,4-benzoxazine derivatives: Structural analysis and DFT calculations

The synthesis and XRD characterization of two new 1,4-benzoxazine derivatives (3a-5a) namely ethyl‐6‐nitro‐3a‐(p‐tolylamino)‐1,2,3,3a‐tetrahydrobenzo[b]cyclopenta[e][1,4]oxa-zine‐9a(9H)‐carboxylate (3a) and methyl-6,10b-dimethyl-5a,6,10b,11-tetrahydrobenzo[5,6][1,4]oxazino[2,3-b]indole-2-carboxylate (5a) are reported herein. In both compounds it is observed the formation of π···π and CH···π interactions and strong NH···O H-bonds, which were studied energetically at the PBE0-D3/def2-TZVP level of theory. The Hisrhfeld surface and QTAIM analyses and NCI plots were used to study the nature and the extent of different intermolecular interactions observed in both structures, revealing the existence of additional R21(6) and R21(7) synthons. In addition, using the potential energy density as energy predictor, the QTAIM method is useful to investigate the relative contribution of each interaction to the formation of the assemblies.