Non-covalent Interaction Analysis Research Articles

Theoretical study on the capture of toxic gases by ionic liquids encapsulated in assembled belt[14[pyridine

In the current study, self-assembled belt[14]pyridine (BP) encapsulated IL (tetramethylammonium chloride (TMACl)) is theoretically explored to capture greenhouse gases (GHGs) at B3LYP-D3/6-311G(d,p) level of theory. The encapsulation of TMACl in assembled belt[14]pyridine is thermodynamically feasible as revealed through high interaction energy value of −50.7 kcal/mol. Moreover, the results of capturing of gas molecules (SO2, CO2, CO and CH4) show that attractive forces involved in capturing of gases are strong van der Waals forces i.e., London dispersion forces and electrostatic interactions. The synergic effect of self-assembled belts and ionic liquid results in significantly high interaction energy values ranging from −7.88 to −25.92 kcal/mol for capturing of gas molecules. Furthermore, the interaction between BP-TMACl and gas molecules is studied in detail through natural bond orbital (NBO) analysis. NBO results show the charge transfer between the fragments (BP-TMACl and gases) which is further validated through EDD analysis. The charge shifts towards all of the captured gas molecules but the most prominent change in NBO charges is shown by captured SO2. The successful charge transfer indicates better interaction in the designed systems. Additionally, the type and strength of interactions involved in the process of encapsulation is studied through quantum theory of atoms in molecules (QTAIM) and noncovalent interactions (NCI) analysis. NCI analysis clearly shows that gases are captured by BP-TMACl complex through strong van der Waals forces. However, in capturing of SO2, strong electrostatic attractive forces are also involved. The nature of attractive forces is confirmed through QTAIM analysis. Furthermore, the relation between recovery time and desorption energy of captured gas molecules has been studied. The strongest absorption for SO2 results in prolonged recovery time for it (as compared to the other gas molecules). AIMD analysis is performed to find the dynamical stability of assembled-belts before and after loading ionic liquids along with gases to be captured. These results reveal that assembled-belts are suitable for encapsulation of ionic liquids along with capturing of gases. Overall, the best results are shown for SO2 capture. The study intends to deliver valuable information on the important progress in the environmental-remediation field and we hope our work is going to inspire more investigators to provide novel research on such challenging tasks.

Application of statistical physical, DFT computation and molecular dynamics simulation for enhanced removal of crystal violet and basic fuchsin dyes utilizing biosorbent derived from residual watermelon seeds (Citrullus lanatus)

This study investigates the use of watermelon seeds (Citrullus lanatus), a plentiful and cost-effective biosorbent, for the removal of basic fuchsin (BF) and crystal violet (CV) dyes from aqueous solutions. Characterization of the biosorbent was conducted using Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM), while Brunauer–Emmett–Teller (BET) analysis revealed a specific surface area (SBET) of 54.50 m² g−1, highlighting its mesoporous structure advantageous for adsorption. Adsorption isotherms were best described by the Langmuir model, indicating monolayer adsorption with high correlation coefficients (R² values of 0.9959 for CV and 0.9978 for BF) and notable adsorption capacities of 139.2493 mg g−1 for CV and 238.80501 mg g−1 for BF. Thermodynamic analysis confirmed the spontaneous and exothermic nature of the adsorption, driven by molecular interactions. To elucidate the adsorption mechanism at the molecular level, we employed Density Functional Theory (DFT) calculations, Molecular Dynamics (MD) simulations, and Non-Covalent Interaction (NCI) analysis. These computational methods provided insights that closely aligned with experimental data, establishing a robust theoretical-experimental framework for understanding dye adsorption by watermelon seed biosorbent. The practical implications of our findings are significant, suggesting that watermelon seed biosorbent can be effectively scaled up for industrial effluent treatment in continuous systems. The study underscores the potential of utilizing this sustainable and economically viable biosorbent for environmental remediation, offering a promising alternative to conventional adsorbents with its high efficiency and lower sensitivity to environmental conditions such as pH and temperature.

A combined experimental and theoretical approach for doxycycline sensing using simple fluorescent probe with distinct fluorescence change in wide range of interferences

Overuse of doxycycline (DOXY) can cause serious problems to human health, environment and food quality. So, it is essential to develop a new sensing methodology that is both sensitive and selective for the quantitative detection of DOXY. In our current research, we synthesized a simple fluorescent probe 4,4′-bis(benzyloxy)-1,1′-biphenyl (BBP) for the highly selective detection of doxycycline by through fluorescence spectroscopy. The probe BBP displayed ultra-sensitivity towards doxycycline due to Forster resonance energy transfer (FRET). Fluorescence spectroscopy, density functional theory (DFT), 1H NMR titration, UV–Vis, and Job's plot were used to confirm the sensing mechanism. The charge transfer between the probe and analyte was further examined qualitatively by electron density differences (EDD) and quantitively by natural bond orbital (NBO) analyses. Whereas the non-covalent nature of probe BBP towards DOXY was verified by theoretical non-covalent interaction (NCI) analysis as along with Bader's quantum theory of atoms in molecules (QTAIM) analysis. Furthermore, probe BBP was also practically employed for the detection of doxycycline in fish samples, pharmaceutical wastewater and blood samples.

Enhanced reactivity and selective adsorption: Unveiling the potential of metal-decorated graphene membranes for biosensing

This study investigates the structural, stability, electronic, and optical properties of finite graphene membranes through a comprehensive computational analysis. The 2D membranes are constructed from hexagonal graphene quantum dots and are decorated with Co, Mn, and Ni. Stability assessments, based on binding energies, affirm the stable formation of the 2D membrane and its derivatives. Electronic investigations reveal a reduction in the energy gap upon metal decoration, indicating enhanced reactivity. Membrane studies demonstrate effective adsorption of creatinine and uric acid on both edge and surface sites, supported by negative adsorption energies. Electronic transitions and absorption spectra shifts indicate dynamic interactions, emphasizing the materials' potential for selective molecular separation. Non-covalent interaction analysis confirmed the role of van der Waals interactions in creatinine and uric acid adsorption. Overall, the findings suggest that the graphene membrane and its decorated derivatives hold promise for selective adsorption applications, especially in the context of biosensing.

Bistriazolotriazole-tetramine: commendable energetic moiety and cation.

Various 7H,7'H-[6,6'-bi[1,2,4]triazolo[4,3-b][1,2,4]triazole]-3,3',7,7'-tetramine (A) based nitrogen-rich energetic salts were designed and their properties explored. All energetic salts possess relatively high nitrogen content (> 48%), positive heats of formation (> 429kJ/mol) and stability owing to a significant contribution from fused backbone. The cationic component shows a very high heat of formation (2516kJ/mol); therefore, it is highly suitable for enthalpy enhancement in new energetic salts. The cation was paired with the energetic anions nitrate (NO3-), perchlorate (ClO4-), dinitromethanide (CH(NO2)2-), trinitromethanide (C(NO2)3-), nitroamide (NHNO2-), and dinitroamide (N(NO2)2-) to improve oxygen balance and detonation performance. Designed salts show moderate detonation velocities (7.9-8.7 km/s) and pressures (23.8 - 33.1 GPa). The distribution of frontier molecular orbitals, molecular electrostatic surface potentials, QTAIM topological properties, and noncovalent interactions of designed salts were simulated to understand the electronic structures, charge distribution in molecules, hydrogen bonding, and other nonbond interactions. The predicted safety factor (SF) and impact sensitivity (H50) of designed salts suggest their insensitivity to mechanical stimuli. This work explored the 7H,7'H-[6,6'-bi[1,2,4]triazolo[4,3-b][1,2,4]triazole]-3,3',7,7'-tetramine as a suitable cationic component which could be promising and serve exemplarily in energetic materials. The optimization and energy calculations of all the designed compounds were carried out at the B3LYP/6-311 + + G(d,p) and M06-2X/def2-TZVPP levels, utilizing the Gaussian software package. The molecular surface electrostatic potential, quantum theory of atoms in molecules (QTAIM), reduced density gradient (RDG), and noncovalent interaction (NCI) analysis were performed by employing Multiwfn software. The EXPLO5 (v 7.01) thermochemical code and PILEM web application were used to predict the detonation properties.

The first-principles study of pure and doped g-CN nanosheet as a drug delivery system

Nanomaterials are increasingly being studied for their potential to serve as drug delivery systems that can transport anticancer drugs directly to tumor cells, thereby minimizing side effects and enhancing treatment effectiveness. This innovative application of nanotechnology holds significant promise in the field of biomedicine. Within the current piece of research, pure graphitic carbon nitride nanosheet (PC3NNS) and Si-doped C3NNS (C3NNS) were selected as a drug delivery system (DDS) for examining the distribution and bioavailability of 6-Mercaptopurine (6-MP) on cancerous cells through the DFT. After doping the Si atom, the attributes of PC3NNS changed, thereby increasing the adhesion process of 6-MP. The adhesion energy of the Si@C3NNS was in the range of 5.5 eV, which demonstrated that it was highly stable. The current work demonstrated the poor adhesion of 6-MP on the PC3NNS with the adhesion energy of approximately −1.72 eV and −2.83 eV in water and gaseous phases respectively. The adhesion energy increased by around 96.21 % after the Si atom was doped on the PC3NNS. The non-covalent interaction (NCI) analysis and the reduced density gradient (RDG) map analysis were performed to examination the main interactions between nanosheet and drug. It was demonstrated that NCIs played a key role in the adhesion of 6-MP in the complex of 6-MP@Si-C3N. Moreover, the NCI analysis demonstrated the significant impact of van der Waals interactions upon the interactions between 6-MP and the nanosheets. The current work can provide insights into the application of C3NNSs as promising drug carriers for many drugs in targeted DDSs.

Investigating structural dynamics and sensing capabilities: Spectroscopic and DFT analysis of novel AIEE active deferasirox based organic sensor

A deferasirox based sensor DPA was rationally designed through single step amidation reaction. Sensor DPA exhibited aggregation induced emission enhancement (AIEE) property that was attributed to restriction in intramolecular rotation (RIR). Moreover, the sensor DPA displayed remarkable bathochromic shift (red-shift) of 110 nm in wavelength, ascribed to formation of J-aggregates. Furthermore, sensor DPA was employed for the selective and sensitive fluorescence based sensing of hazardous and carcinogenic nitrobenzene (NB). The sensor DPA successfully detected NB in solution through the quenching of emission intensity. The quenching of sensor fluorescence intensity was ascribed to photoinduced electron transfer (PET) mechanism. The sensing mechanism was investigated by 1H NMR titration experiment, Job's plot and density functional theory (DFT) calculations. Additionally, the existence of non-covalent interactions between sensor DPA and NB were examined by Bader's Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analysis. Finally, sensor DPA was employed for the detection of volatile nitrobenzene in vapor phase.

Solvent efficiency and role of dispersion and electrostatic forces for chiral discrimination of sulfur-containing amino acids by tetra-protonated CBPQT macrocycle

Two enantiomeric forms of amino acids in a chiral medium behave quite differently because of the different orientation of their functional groups in space. Thus, the phenomenon of chiral recognition is crucial with the focus on applications in molecular sensing and enantioselective separations. The present research work is focused on the illustration of the potential chiral recognition of a porous CBPQT4+ macrocycle for sulfur-containing amino acids, which is elucidated by the conformational energies landscape with quantitative non-covalent analysis and their electronic behaviour. Herein, we report the chiral recognition of sulfur-containing amino acids e.g., cysteine (CY), homocysteine (HCY), and methionine (MT), by tetra-protonated (4+) CBPQT macrocycle via density functional theory (DFT) calculations. Geometry optimization, thermodynamic stability, noncovalent interaction analysis, symmetry-adapted perturbation (SAPT), and electronic properties analyses are employed to characterize the chiral response of the complexes formed by CBPQT4+ with D- and L-isomers of selected amino acids. The interactive conformations of complexes indicate physisorption of amino acids through the central cavity of the macrocycle. The maximum chiral discrimination is observed in the case of D- and L-cysteine isomers, which is 3.56 kcal/mol. It is revealed that the complex; D-CY@CBPQT4+ is energetically more stable than the L-CY analogue, whereas, L-HCY and L-MT show higher stability as compared to D-type counterparts, probably due to the interaction of the thiol groups with π-electrons of macrocycle in respective stable complexes. Non-covalent interaction (NCI) analyses including, reduced density gradient-based NCI index and SAPT reveal that the methionine-based complexes show the highest attractive components e.g., electrostatic, dispersion, and induction with the lowest repulsive exchange contribution, which is followed by homocysteine and cysteine. Overall, results show that the CBPQT4+ macrocycle has an excellent ability to differentiate between L- and D-amino acids, the difference is more pronounced when the structure of amino acid is small and rigid.

Hydrogen Bonding and Molecular Geometry in Isolated Hydrates of 2-Ethylthiazole Characterised by Microwave Spectroscopy.

Broadband microwave spectra of the isolated 2-ethylthiazole molecule, and complexes of 2-ethylthiazole⋅⋅⋅H2O and 2-ethylthiazole⋅⋅⋅(H2O)2 have been recorded by probing a gaseous sample containing low concentrations of 2-ethylthiazole and water within a carrier gas undergoing supersonic expansion. The identified conformer of the isolated 2-ethylthiazole molecule and the 2-ethylthiazole sub-unit within each of 2-ethylthiazole⋅⋅⋅H2O and 2-ethylthiazole⋅⋅⋅(H2O)2 have C1 symmetry. The angle that defines rotation of the ethyl group relative to the plane of the thiazole ring, ∠(S-C2-C6-C7), is -98.6(10)° within the isolated 2-ethylthiazole molecule. Analysis of molecular geometries and non-covalent interactions reveals each hydrate complex contains a non-linear primary, N⋅⋅⋅Hb-O, hydrogen bond between an O-H of H2O and the nitrogen atom while the O atom of the water molecule(s) interacts weakly with the ethyl group. The ∠(Hb⋅⋅⋅N-C2) parameter, which defines the position of the H2O molecule relative to the thiazole ring, is found to be significantly greater for 2-ethylthiazole⋅⋅⋅H2O than for thiazole⋅⋅⋅H2O. The distance between the O atoms is determined to be 2.894(21) Å within the dihydrate complex which is shorter than observed within the isolated water dimer. The primary hydrogen bond within 2-ethylthiazole⋅⋅⋅(H2O)2 is shorter and stronger than that in 2-ethylthiazole⋅⋅⋅H2O as a result of cooperative hydrogen bonding effects.

Comprehensive Study on the Adsorption and Degradation of Dichlorodiphenyltrichloroethane on Bifunctional Adsorption-Photocatalysis Material TiO2/MCM-41 Using Quantum Chemical Methods.

The adsorption and degradation capacities of dichlorodiphenyltrichloroethane (DDT) on a photocatalyst composed of TiO2 supported on the mesoporous material MCM-41 (TiO2/MCM-41) were investigated using density functional theory and real-time density functional theory methods. The van der Waals interactions within the PBE functional were adjusted by using the Grimme approach. The adsorption of DDT was evaluated through analyses involving adsorption energy, Hirshfeld atomic charges, Wiberg bond orders, molecular electrostatic potential, noncovalent interaction analysis, and bond path analysis. The findings reveal that DDT undergoes physical adsorption on pristine MCM-41 or MCM-41 modified with Al or Fe due to the very small bond order (only about 0.15-0.18) as well as the change in total charge of DDT after adsorption is close to 0. However, it chemically adsorbs onto the TiO2/MCM-41 composite through the formation of Ti···Cl coordination bonds because the maximum bond order is very large, about 1.0 (it can be considered as a single bond). The adsorption process is significantly influenced by van der Waals interactions (accounting for approximately 30-40% of the interaction energy), hydrogen bonding, and halogen bonding. MCM-41 is demonstrated to concurrently function as a support for the TiO2 photocatalyst, creating a synergistic effect that enhances the photocatalytic activity of TiO2. Based on the computational results, a novel photocatalytic mechanism for the degradation of DDT on the TiO2/MCM-41 catalyst system was proposed.

Theoretical Investigation Non-covalent Interactions of N-(diphenylphosphinothioyl)-2-pyrazinecarboxamide

Abstract. Phosphine chalcogenides can form reliable and reproducible supramolecular synthons through noncovalent interactions that can be employed for designing high dimensional supramolecular architectures. Here, we systematically study the influence of non-covalent interactions in the fabrication of these synthons and the stability of the crystalline structure of (N2C4H3)C(O)NHP(S)(C6H5)2 (1) through non-covalent interactions (NCI) analysis, molecular Hirshfeld surfaces and the corresponding two-dimensional (2D) fingerprint plots. The theoretical studies were employed to further confirm the presence of these synthons by comparing the stabilization energies of the dimers and monomers. The nature and electronic structure of the phosphor-chalcogenid bond in (N2C4H3)C(O)NHP(E)(OC6H5)2(E = S(1), O(2), and Se (3)) have also been evaluated by QTAIM, NBO, MEP, and HOMO-LUMO energy gaps.

Exploration of one-dimensional hydrogen bonding organic framework (1D-HOF) and charge transfer dynamics in N’-benzylbenzohydrazide: A comprehensive structural and quantum computational investigation

This study presents a comprehensive structural analysis of N’-benzylbenzohydrazide (NBBH) using experimental and computational techniques, shedding light on its non-covalent interactions and charge transfer dynamics. Single crystal X-ray diffraction studies confirm the three-dimensional molecular structure with high precision, revealing an orthorhombic crystal system and non-planarity of the NBBH molecule. Supramolecular interactions, including hydrogen bonds and short intermolecular interactions, are investigated, forming the basis for the assembly of molecular entities into extensive frameworks. Hirshfeld surface analysis provides insights into the intermolecular interactions in the crystal system, with the visualization of hydrogen bonds and short contacts. Energy framework analysis further explores pairwise interaction energies, emphasizing the role of dispersive forces in stabilizing the crystal lattice. Density functional theory studies, including molecular orbital analysis and global chemical reactivity descriptors, offer a deeper understanding of the electronic structure, redox potential, and charge transfer properties of NBBH. Natural bond orbital analysis reveals the charge transfer mechanism within the 1D Hydrogen-Bonded Organic chain, highlighting hyperconjugative interactions contributing to the stabilization of the molecule. Non-covalent interaction analysis using the Reduced Density Gradient method visualizes intra and intermolecular interactions, providing valuable insights into the formation and stability of the 1D network chain in the crystal structure of NBBH. Reorganization energy is discussed in the context of electron and hole transfer processes, emphasizing its importance in understanding the charge transfer dynamics within the molecular framework. The observed inverse relationship between reorganization energy and charge mobility contributes a key insight into the stability and conductivity of the material. The electron charge density distribution analysis, provides a detailed spatial distribution of electrons within the NBBH molecule. The findings have implications for understanding the molecular properties and potential applications of NBBH in various fields.

4D-QSAR and MIA-QSAR Studies of Aminobenzimidazole Derivatives as Fourth-generation EGFR Inhibitors.

The epidermal growth factor receptor (EGFR) protein has been intensively studied as a therapeutic target for non-small cell lung cancer (NSCLC). The aminobenzimidazole derivatives as the fourth-generation EGFR inhibitors have achieved promising results and overcame EGFR mutations at C797S, del19 and T790M in NSCLC. In order to understand the quantitative structure-activity relationship (QSAR) of aminobenzimidazole derivatives as EGFRdel19 T790M C797S inhibitors, the four-dimensional QSAR (4D-QSAR) and multivariate image analysis (MIA-QSAR) have been performed on the data of 45 known aminobenzimidazole derivatives. The 4D-QSAR descriptors were acquired by calculating the association energies between probes and aligned conformational ensemble profiles (CEP), and the regression models were established by partial least squares (PLS). In order to further understand and verify the 4D-QSAR model, MIA-QSAR was constructed by using chemical structure pictures to generate descriptors and PLS regression. Furthermore, the molecular docking and averaged noncovalent interactions (aNCI) analysis were also performed to further understand the interactions between ligands and the EGFR targets, which was in good agreement with the 4D-QSAR model. The established 4D-QSAR and MIA-QSAR models have strong stability and good external prediction ability. These results will provide theoretical guidance for the research and development of aminobenzimidazole derivatives as new EGFRdel19 T790M C797S inhibitors.

Hierarchical Self‐Assembly of Curved Aromatics: From Donor–Acceptor Porphyrins to Triply Periodic Minimal Surfaces

AbstractA saddle‐shaped π‐extended zinc porphyrin containing a peripheral pyridyl ligand undergoes quantitative self‐assembly into a cyclic trimer. The trimer has a prismatic structure with negatively curved side walls, which promote the formation of supramolecular organic frameworks stabilized by dispersion interactions. The first framework type, UWr‐1, has the npo topology, with a hexagonal structure analogous to the Schwartz H triply periodic minimal surface. Co‐crystallization of the trimer with either C60 and C70 produces the isomorphous cubic UWr‐2 and UWr‐3 phases, characterized by the ctn network topology and a structural relationship to the Fischer‐Koch minimal surface S. All three phases contain complex labyrinths of solvent‐filled channels, corresponding to very large probe‐accessible volumes (68 % to 76 %). The UWr‐2 network could be partly desolvated while retaining its long range dimensional order, indicating remarkable strength of the dispersion interactions in the crystal. A theoretical analysis of noncovalent interactions shows the role of geometrical matching between the negatively curved porphyrin units and positively curved fullerenes.

Hierarchical Self-Assembly of Curved Aromatics: From Donor-Acceptor Porphyrins to Triply Periodic Minimal Surfaces.

A saddle-shaped π-extended zinc porphyrin containing a peripheral pyridyl ligand undergoes quantitative self-assembly into a cyclic trimer. The trimer has a prismatic structure with negatively curved side walls, which promote the formation of supramolecular organic frameworks stabilized by dispersion interactions. The first framework type, UWr-1, has the npo topology, with a hexagonal structure analogous to the Schwartz H triply periodic minimal surface. Co-crystallization of the trimer with either C60 and C70 produces the isomorphous cubic UWr-2 and UWr-3 phases, characterized by the ctn network topology and a structural relationship to the Fischer-Koch minimal surface S. All three phases contain complex labyrinths of solvent-filled channels, corresponding to very large probe-accessible volumes (68 % to 76 %). The UWr-2 network could be partly desolvated while retaining its long range dimensional order, indicating remarkable strength of the dispersion interactions in the crystal. A theoretical analysis of noncovalent interactions shows the role of geometrical matching between the negatively curved porphyrin units and positively curved fullerenes.

Investigating the adsorption potential and sensitivity of pristine along with carbon, boron, and nitrogen substituted hetero-nanocages towards azacitidine drug

The use of nanomaterials as carriers for the delivery of a diverse array of anticancer drugs and their application as effective sensors in clinical environments has been steadily growing as a result of advancements in nanoscience. Using density functional theory at the B3LYP-D3/6-31G(d,p) level, this study made a comparative adsorption efficiency assessment of pure C24 and B12N12 nanocages along with some of their hetero-counterpart nanocages toward the anticancer drug azacitidine. Out of the nanostructures that were examined in this study, B6C6N12 nanocage appeared as the most prominent adsorbent by developing drug delivery conjugated structure that demonstrates the highest degree of stability in adsorbing the azacitidine, making it most suitable for transportation or detection purposes in both gaseous and aqueous environments. The confirmation of the interaction between the azacitidine and the adsorbents is further supported by examining frontier molecular orbitals, natural bond orbital, quantum theory of atoms in molecules, and non-covalent interaction analysis. The simulation of ultraviolet–visible spectra was performed for all systems to assess the feasibility of using ultraviolet–visible spectroscopy to track and monitor the binding of azacitidine to the suggested adsorbents. The findings presented here open up endless possibilities for these nanocages as drug delivery and detection systems of nanomedicine.

Hydantoin-D,L-valine: Synthesis, characterization, and non-covalent interaction analysis from crystallographic studies, DFTB calculations, and Hirshfeld surface analysis

The title compound, hydantoin-D,L-daline or (RS)-5-isopropyl-imidazolidine-2,4‑dione, a new amino acid hydantoin derivative with formula C6H10N2O2 has been synthesized and structurally characterized by FT-IR, NMR, and X-ray diffraction techniques. Spectroscopy results are consistent with the skeleton structure. The powder X-ray diffraction data confirms the phase purity of the crystalline sample. Single-crystal X-ray diffraction analysis indicated that the title compound crystallizes in the monoclinic space group P21/c (N°14), Z = 4, and unit cell parameters a = 5.493(3) Å, b = 23.53(2) Å, c = 6.254(3) Å, β= 115.09(4)°, V = 732.1(9) Å3. The molecular structure and crystal packing are stabilized by intermolecular N–H···O, C–H···O, and C–H···π hydrogen bonds forming an infinite two-dimensional network with chains described by the graph-set notation C(5), and centrosymmetric rings with graphs R22(8) and R44(16). The non-covalent interactions were analyzed employing DFTB calculations, which reproduce the main features of the stereochemistry and geometries exhibited by X-ray diffraction. Additionally, these intermolecular interactions were analyzed using Hirshfeld surfaces analysis and 2D fingerprint plots.

Insights into the Mechanism, Regio-/Diastereoselectivities and Ligand Role of Nickel-Initiated [3+2] Cycloadditions between Vinylcyclopropane and N-Tosylbenzaldimine

Density functional theory (DFT) was employed to explore the reaction mechanism, regio- and diastereoselectivities of nickel-initiated [3+2] cycloaddition between vinylcyclopropane (VCP) and N-tosylbenzaldimine assisted by phosphine ligands. Four different binding modes of the nickel center to VCP substrate were explored during the ring-opening of VCP, among which the C,C_anti and C,C_syn modes were verified to be the most accessible ones. Further explorations about four different phosphine ligand-assisted reactions based on the two most probable binding modes show that the difference in binding mode of bi- and monodentate phosphine ligands can vary the optimal reaction pathway, especially in the [3+2] cycloaddition process between the ring-opened intermediate and N-tosylbenzaldimine. The formation of C–C and C–N bonds between N-tosylbenzaldimine and the ring-opened intermediate through [3+2] cycloaddition is found to be stepwise, with the former acting as the rate-determining step (RDS) in most cases. Computed free energy barriers of RDS transition states on the optimal path I or II not only give out good predictions for reaction rates and half-lives, but also provide reasonable explanations for the major generation of cis-pyrrolidine. Noncovalent interaction analyses of key stationary points suggest the rate is influenced by both electronic effects and steric hindrance, while the diastereoselectivity is mainly controlled by electronic effects.

High-Density Energetic Materials with Low Mechanical Sensitivity and Twinning Derived from Nitroimidazole Fused Ring.

The innovative synthesis of 3,8-dibromo-2,9-dinitro-5,6-dihydrodiimidazo [1,2-a:2',1'-c]pyrazine and 3,9-dibromo-2,10-dinitro-6,7-dihydro-5H-diimidazo [1,2-a:2',1'-c][1,4]diazepine is described in this study. The tricyclic fused molecular structures are formed by the respective amalgamation of piperazine and homopiperazine with the imidazole ring containing nitro. Compound 1 and 2 possess excellent high-density physical properties (ρ1 = 2.49 g/cm3, ρ2 = 2.35 g/cm3) due to the presence of a fused ring structure and Br atom. In addition to their high density, they have high decomposition temperatures (Td > 290 °C) which means that they have excellent thermal stability and can be used as potential heat-resistant explosives. Low mechanical sensitivities (IS > 40 J, FS > 360 N) are observed. The twinning structure of 2 was resolved by X-ray diffraction. Non-covalent interaction analysis, Hirshfeld surfaces, 2D fingerprint plot, and Electrostatic potential analysis were used to understand the intramolecular interactions in relation to physicochemical properties. The unique structures of this type of compound provide new potential for the evolution of energetic materials.

Computational analysis of anti-cancer drug hydroxyurea adsorption on nanocages of gold, silver and copper: SERS and DFT assessment

The use of nanostructures in targeted drug delivery is effective in decreasing anticancer drug toxicity. Here, we discuss the theoretically predicted adsorption and interaction behavior of hydroxyurea [HU] with nano metal cages (nmC). HU interact the nmC through the N4 in primary amine with energies of −29.776, −30.684 and −22.105 kcal/mol for Au, Ag and Cu cage, respectively. As a result of reactivity studies, HU complexes with nmC (Au/Ag/Cu) are becoming more electrophilic and this gives the nmC system their bioactivity. It is suggested that nanocage is going to change the FMO's energy levels by means of absorption, so that it is used in drug administration. DOS and MEP were accomplished to gain additional understandings into the reactivity of proposed complexes. Method for improving the Raman signal of biomolecules is surface enhanced Raman scattering (SERS), which uses nanosized metal substrates. Chemical enhancement is evidenced by Mulliken charge distributions of all systems for detection and chemical compositions and exerts a significant role in determining them. In HU complexes containing nmC (Au/Ag/Cu), electron density was detected via ELF and LOL calculations. Based on the results of a non-covalent interaction (NCI) analysis, Van der Waals/hydrogen bonds/repulsive steric – interactions have been found. The title compound will also be analyzed in order to determine its bioactivity and drug likeness parameters, as a result, we will able to create a molecule with a highly favorable pharmacological profile and use the docking method to determine the values of the interaction energies for drug delivery. This study suggests that adsorption of drugs on nanocage surface occurs physically and functionalizing the nanocage has increased adsorption energy.