Effect Of Non-covalent Interactions Research Articles

Noncovalent Interactions, Structure Elucidation and Docking Studies of anti-Fungal Pyridine Carboxamide Derivatives of Co(II), Ni(II), Cu(II) & Zn(II)

Computational analysis of four antifungal transition metal complexes of Co(II), Ni(II), Cu(II) and Zn(II) with pyridine carboxamide derivates (methyl 2-amino-3- methylbenzoate isonicotinic acid amide (L1) and methyl 2-amino-3-methylbenzoate picolinic acid amide (L2)) as ligands is provided here within the DFT framework. Geometry optimization, binding energy, HOMO-LUMO energy gap, Density of States (DOS) plots, and MEP surfaces have been calculated to rationalize the molecular structure of these complexes. The effect of noncovalent interactions on the crystal structure of these complexes has been deciphered using CE-B3LYP model instigated into CrystalExplorer using experimental geometries accessed from Cambridge Crystallographic Data Center (CCDC). These complexes are docked against Enterococcus Faecalis using AutoDock Vina to quantify binding energy between the complexes and protein accessed from the protein data bank (PDB).

Study of Non-Covalent Interactions Present in the Tapinarof-Ethanol System with Special Emphasis on Hydrogen-Bonding Interactions.

In this study, the effect of non-covalent interaction in the tapinarof-EtOH systems is evaluated, particularly the hydrogen-bonding interaction using density functional theory in a gas phase. From the optimization results and the binding energy calculated thereafter, it is concluded that interaction in the employed system occurs between the O-H groups on tapinarof and the oxygen atom of EtOH molecules existing in the vicinity of the O-H group. These interactions were concluded to be those of the weak hydrogen bonds by carrying out the reduced gradient approach and QTAIM analysis, which are basically electron-density-based topological analyses. The charge localization between the donor-acceptor moieties was analyzed using the NBO analysis. Using the LED analysis, the binding energy between the tapinarof and EtOH was partitioned into different energy terms centered on a domain-based local pair natural orbital coupled cluster method. Thus, the electronic environment of the tapinarof-EtOH systems is evaluated.

Influence of non-covalent interactions on the coordination geometry of Ni(ii) in Ni(ii)–M(ii) complexes (M = Zn and Hg) with a salen-type N2O2 Schiff base ligand and thiocyanate ion as the coligand

The effect of non-covalent interactions on the coordination geometry of Ni(ii) in a Ni(ii)–Zn(ii) and a Ni(ii)–Hg(ii) complexes has been studied using DFT calculations.

Effects of non-covalent interactions between pectin and volatile compounds on the flavor release of tomato paste

Breaking methods have been shown to affect the sensory attributes of tomato paste, including volatile compounds and pectin content. This study aimed to explore the roles of interactions between pectin and aroma active compounds in the flavor release of tomato paste. Based on our results, phenethyl alcohol (PA) was one of the representative aroma active compounds and showed highly negative correlation with pectin content in tomato paste. According to ultraviolet–visible, fluorescence emission spectra and DLS analysis, PA could interact with pectin through hydrophobic and electrostatic interactions. The IGM analysis showed that van der Waals forces played a dominant role in the formation of PA-pectin complexes, which was further confirmed by 1 H NMR spectra and MD simulation. Overall, the non-covalent interaction of volatile compounds with pectin remarkably affected their release in tomato paste. These findings provide some insights into methods for improving the sensory quality of tomato paste. • Volatiles and pectin contents of tomato pastes greatly changed after processing. • PA was one of the representative aroma active compounds in tomato paste. • PA exhibited highly negative correlation with pectin content in tomato paste. • The quenching of PA fluorescence by pectin was based on a static mechanism. • Non-covalent interactions of volatile compounds with pectin affected their release.

DFT calculations, structural analysis, solvent effects, and non-covalent interaction study on the para-aminosalicylic acid complex as a tuberculosis drug: AIM, NBO, and NMR analyses.

In this study, the effect of non-covalent interactions on the para-aminosalicylic acid complex is explored using density functional theory (DFT) in the gas phase and the solution. Our findings exhibit that the achieved binding energies considerably change on going from the gas phase to the solution. Based on the obtained results, the absolute value of the binding energy of the complex in the polar solvents is lower than the non-polar ones while in the gas phase it is higher than the solution. The atoms in molecules (AIM) and the natural bond orbital (NBO) analyses are applied to estimate the topological properties and the charge transfer during complexation, respectively. The results indicate that the presence of the cation-π interaction increases the strength of the intramolecular hydrogen bond in the studied complex. Finally, the various electronic descriptors such as energy gap, hardness, softness, and electronic chemical potential are investigated to gain further insight into these interactions. According to the achieved results, the high energy gap of the complex in the water solvent indicates high chemical stability and low reactivity compared to the others. On the other hand, the most reactive as well as the softest complex belongs to the gas phase.

Effect of Non-Covalent Interactions on the 2,4- and 3,5-Dinitrobenzoate Eu-Cd Complex Structures

Heterometallic {Eu2Cd2} complexes [Eu2(NO3)2Cd2(Phen)2(2,4-Nbz)8]n·2nMeCN (I) and [Eu2(MeCN)2Cd2(Phen)2(3,5-Nbz)10] (II) with the 2,4-dinitrobenzoate (2,4-Nbz) and 3,5-dinitrobenzoate (3,5-Nbz) anions and 1,10-phenanthroline were synthesized. The compounds obtained were characterized by X-ray single-crystal analysis, powder X-ray diffraction analysis, IR spectroscopy, and elemental analysis. Moreover, the thermal stability of the complexes was also studied. Analysis of the crystal packing showed that where 1,10-phenanthroline is combined with various isomers of dinitrobenzoate anions, different arrangements of non-covalent interactions are observed in the complex structures. In the case of the compound with the 2,4-dinitrobenzoate anion, these interactions lead to a significant distortion of the metal core geometry and formation of a polymeric structure, while the complex with the 3,5-dinitrobenzoate anion has a structure that is typical of similar systems. The absence of europium metal-centered luminescence at 270 nm wavelength was shown. For all the reported compounds, a thermal stability study was carried out that showed that the compounds decomposed with a significant thermal effect.

Recent advances in studying the nonnegligible role of noncovalent interactions in various types of energetic molecular crystals

This highlight summarizes the research progress on the considerable effects of noncovalent interactions on diverse types of energetic materials and enlighten us to explore new factors that affect the key performance of explosives.

Effects of the non-covalent interactions between polyphenols and proteins on the formations of the heterocyclic amines in dry heated soybean protein isolate

Soybean proteins are the main component of plant‐based meat alternatives in the Chinese market. The effects of non-covalent interactions between polyphenols and proteins on the protein structures, the rest physicochemical properties, and formations of heterocyclic amines (HAs) were examined using a polyphenols-containing soybean protein isolate (SPI) complex as a model to dry heating at 170℃ for 10 min. The results showed that tetrahydro-curcumin had extensive inhibitory effects on the HA formation. In addition, tea polyphenols, grapeseed procyanidins, and dihydromyricetin were also found to have inhibitory effects only on some HAs. Correlation analysis showed that polyphenols altered the secondary structure and steric structure of the protein by interacting with the protein, which affects the HA formation. The results provided theoretical references and a basis for the formation mechanisms of HAs in polyphenol-inhibiting protein foods.

Beyond Conformational Control: Effects of Noncovalent Interactions on Molecular Electronic Properties of Conjugated Polymers.

Tuning the electronic properties of polymers is of great importance in designing highly efficient organic solar cells. Noncovalent intramolecular interactions have been often used for conformational control to enhance the planarity of polymers or molecules, which may reduce band gaps and promote charge transfer. However, it is not known if noncovalent interactions may alter the electronic properties of conjugated polymers through some mechanism other than the conformational control. Here, we studied the effects of various noncovalent interactions, including sulfur–nitrogen, sulfur–oxygen, sulfur–fluorine, oxygen–nitrogen, oxygen–fluorine, and nitrogen–fluorine, on the electronic properties of polymers with planar geometry using unconstrained and constrained density functional theory. We found that the sulfur–nitrogen intramolecular interaction may reduce the band gaps of polymers and enhance the charge transfer more obviously than other noncovalent interactions. Our findings are also consistent with the experimental data. For the first time, our study shows that the sulfur–nitrogen noncovalent interaction may further affect the electronic structure of coplanar conjugated polymers, which cannot be only explained by the enhancement of molecular planarity. Our work suggests a new mechanism to manipulate the electronic properties of polymers to design high-performance small-molecule-polymer and all-polymer solar cells.

Effect of Noncovalent Interactions on the Intersystem Crossing Behavior in Charge-Transfer Cocrystals of 3,5-Dinitrobromobenzene

The strength of the noncovalent interactions between donor and acceptor in charge-transfer (CT) cocrystals plays a significant role in controlling their optical behavior. Herein, we demonstrate the...

Stability of spherical molecular complexes: a theoretical study of self-assembled M12L24 nanoballs

Supramolecular coordination complexes have become of great interest due to their broad spectrum of applicability, mainly in the area of biomedicine. Understanding the role played by the metal center and the weak interactions in the formation and stabilization of these compounds allow us to have a better design of these molecules and therefore a better guide for the examination of novel applications. In this work, we investigate the effect of noncovalent interactions and the presence of metal centers in the stabilization of Tominaga’s M12L24 nanoballs. We considered bis(4-pyridyl)-substituted bent frameworks involving two acetylenes spacers as the ligand (L), using –H, –CH3, and a cyanophenyl group as substituents, and two different metal cations: Pd2+ and Ni2+. We found that the bond distance between the metal and the ligand was smaller for the nickel complexes than for the palladium compounds. This is related to the dissociation energies (Ni2+ systems are more stable than Pd2+ compounds). Furthermore, nanoballs with the largest ligand’s substituent are significantly more stable than those with the smallest ligand’s substituents. Analyzing the frontier states and the Independent Gradient Model isosurfaces, we found that noncovalent interactions contribute to the stabilization of the complexes. Through the charge distribution, we observed that the metal also polarizes the density of the coordination bond. With these results we can conclude that metal centers and noncovalent interactions play an important role in the stabilization of nanoballs.

Improving photovoltaic performance of benzothiadiazole-based small molecules: A synergistic effect of non-covalent interaction and aryl terminal group

Abstract

Effects of non-covalent interactions on the properties of 3D printed flexible piezoresistive strain sensors of conductive polymer composites

ABSTRACT In this work, flexible piezoresistive strain sensors of carbon nanotubes (CNT)/thermoplastic polyurethane (TPU) conductive polymer composites were prepared using fused filament fabrication (FFF) 3D printing. The constructed porous structure and highly elastic TPU matrix allow the sensors to experience strains up to 30% with great recoverability. The printed sensors exhibited a typical negative piezoresistive effect under compressive strain. The effects of non-covalent modification and loading of CNTs on the mechanical and piezoresistive behavior of sensors were investigated. The introduction of 1-pyrenecarboxylic acid (PCA) increased the dispersibility of CNTs and nanofiller-polymer interfacial interactions, resulting in the excellent sensing performance. A sensor with higher CNT content showed greater sensitivity due to generation of more conductive paths during compression. The gauge factor () of the 3 wt% CNT/PCA/TPU sensor increased by 43 and 35 times compared with the 3 wt% CNT/TPU and the 1.5 wt% CNT/PCA/TPU sensors, respectively, when strained at 26% to 30%. In addition, the printed sensor of 3 wt% CNT/PCA/TPU showed great reproducibility over 1500 loading cycles. Some applications in monitoring external loads and motion of the human body were demonstrated. This work provides important information for the property optimization and customizable fabrication of flexible piezoresistive strain sensors.

Qualitative as well as quantitative analysis of interactions present in chlorine and bromine substituted aromatic organic crystals: A DFT linked Crystal Explorer study

The effect of noncovalent interactions in shaping a crystal structure is explored qualitatively as well as quantitatively in a DFT linked Crystal Explorer (CE) study of nine different Chlorine and Bromine substituted benzene derivatives. The qualitative approach to analyze interactions is based on Hirshfeld surface that locates electronic charge distribution on the surface, quantitative estimation is obtained by linking DFT computations withCE.In the halogen substituted benzene derivatives considered here, in addition to conventional hydrogen and halogen bonding other interactions such as those between Chlorine–Hydrogen, Bromine–Hydrogen, Bromine-Oxygen have been deciphered. The molecular crystal structure of a variety of halogen substituted aromatic molecules has been rationalized and attributed to specific interactions.

Mixed ligand coordination complexes by using multicomponent ligand: Syntheses, characterization and effect of non-covalent interactions on their framework structures

Abstract Three new coordination complexes [Mn(L1)(μ-azide)(azide)]2⋅4H2O (1), [Mn(L1)(fum)]n (2) [L1 = 2methyl-N1,N2-bis(pyridin-2yl)propane-1,2-diamine, fum = Fumaric acid] and [Co(L2)(azide)] (3) [L2 = 6 phenyl-1,3,5-triazine 2,4-diyl amino(pyridine-2yl)methanol] have been synthesized and X-ray crystallographically characterized. Complex 1, a dinuclear Mn(II) complex is formed by bridging azide ligand and other coordination sites are satisfied by tetradentate ligand L1 and terminal azide ligand. The overall structure is an incomplete supramolecular 3D cage structure, formed by intermolecular π … π interaction of pyridyl ligand and hydrogen bonding. Complex 2 comprised of eight coordinated Mn(II) centre where ligand L1 and fumarate is bridged between the metal centers that leads to a one dimensional chain structure which further extended to a 3D structure by π … π and C–H … π interactions. The overall structure is further stabilized by hydrogen bonding with the guest water molecules. Complex 3, a six coordinated mononuclear Co(II) discrete complex is consist of pentadentate ligand L2 and azide act as a terminal ligand. This Mononuclear complex is connected by π … π, C–H … π interactions and hydrogen bonding which ultimately leads to a supramolecular 2D architecture. All the complexes have been further characterized by elemental analysis, infrared spectroscopy (IR) and powder X-ray diffraction (PXRD) studies.

Conformational analysis of ticagrelor: effect of noncovalent interaction on conformational population

In order to track the source of duplicated peaks in the 1H-NMR spectrum of Ticagrelor, variable-temperature NMR (VT-NMR) experiment was carried out with temperature increasing from 300 to 343 K. The result showed that the phenomenon was brought forth by coexistence of conformational isomers. Subsequently, conformational search was carried out by molecular mechanics (MM) stimulations associating with quantum mechanics (QM) calculations. The results revealed that the isomers resulting in duplicated proton peaks were introduced by the rotation of 2,4-diflurophenyl group on C3’position of cyclopropyl. Finally, noncovalent interaction (NCI) topological analysis of the conformers exhibited that CH-π interactions and H-bonds play important roles in controlling the population of conformers of ticagrelor.

Effect of non-covalent interactions on molecular stacking and photovoltaic properties in organic photovoltaics

The conjugated structures of donor–acceptor (D–A) type with sulfur (S), nitrogen (N) and oxygen (O) atoms aid to close packing each other in the backbone by non-covalent interactions. Furthermore, non-covalent interactions are exerted three dimensionally and affect various properties. To know this effects, we introduced different S, N and O contents as benzothiadiazole (BT) and dithienophenazine (DTPz, up or down direction of S) units on each polymer backbone. Among the three polymers, P2 with up direction of S showed an open-circuit voltage (Voc) of 0.90V, fill factor (FF) of 54.7% and reached best power conversion efficiency (PCE) of 4.8%.

Effects of non-covalent interactions on the electronic and electrochemical properties of Cu(i) biquinoline complexes

A Cu(i) complex {[CuI(biq)2]ClO4-biq} with biq = 2,2'-biquinoline was prepared, fully characterized and its properties compared with those of the well-known [CuI(biq)2]ClO4 complex. The crystal structures were obtained for both complexes (crystal structure for [CuI(biq)2]ClO4 has not been previously reported). Complex [CuI(biq)2]ClO4 crystallizes as a racemate where each enantiomer has a different τ4 value while compound {[CuI(biq)2]ClO4-biq} crystallizes as a non-chiral supramolecular aggregate with an uncoordinated biq molecule forming a π-π stacking interaction with a coordinated biq. 1H-NMR spectroscopy in non-coordinating solvents reveals that structures in solution are similar to those in the solid phase, confirming the presence of a supramolecular arrangement for compound {[CuI(biq)2]ClO4-biq}. The stability of the non-covalent aggregate in solution of {[CuI(biq)2]ClO4-biq} causes significant differences between the spectroscopic and electrochemical properties of {[CuI(biq)2]ClO4-biq} and [CuI(biq)2]ClO4.

Effects of Noncovalent Interactions on the Catalytic Activity of Unsupported Colloidal Palladium Nanoparticles Stabilized with Thiolate Ligands.

This article presents the systematic evaluation of colloidal palladium nanoparticles functionalized with well-defined small organic ligands that provide spatial control of the geometric and electronic surface properties of nanoparticle catalysts. Palladium nanoparticles stabilized with thiolate ligands of different structures and functionalities (linear alkyl vs cyclohexyl vs phenyl) are synthesized using the thiosulfate protocol in a two-phase system. The structure and composition of palladium nanoparticles are characterized using transmission electron microscopy, thermogravimetric analysis, NMR, and UV-vis spectroscopies. The catalysis studies show that the chemical and structural compositions of monolayers surrounding the nanoparticle core greatly influence the overall activity and selectivity of colloidal palladium nanoparticle catalysts for the hydrogenation, isomerization, and hydrogenolysis of allylic alcohols. Especially, noncovalent interactions between surface phenyl ligands and incoming aromatic substrates are found to have a profound influence on the selectivity of colloidal palladium nanoparticles.

Charge carrier mobility in one-dimensional aligned π-stacks of conjugated small molecules with a benzothiadiazole central unit.

A theoretical study is applied to gain insight into the microscopic electron and hole transport in benzothiadiazole-cored molecular semiconductors either with furan or thiophene flanks arranged in π-stacks. For the characterization of the energetics of the reduction and oxidation processes and their impact on the molecular geometry, the internal reorganization energy is defined for isolated molecules in the gas phase. The outer-shell reorganization energy is evaluated within the frequency-resolved cavity model and as an electrostatic contribution within the polarizable continuum model. The intermolecular electronic coupling interaction for the Marcus charge hopping is calculated using the energy splitting in dimer method, the generalized Mulliken-Hush approach and the fragment charge difference scheme. In order to probe the relation between the charge hopping rate/charge carrier mobility and the molecular organization within the π-stacks, different stacking modes are investigated: (i) dimers with a perfect registry, i.e. segregated stacking motif, when molecules are placed face-to-face, and (ii) dimers forming slipped cofacial orientations with longitudinal and transverse shifts, i.e. mixed stacking motif. Besides, the effects of molecular planarity and rigidity, influencing internal molecular relaxation upon charging, the effects of non-covalent interactions within stacks and the heteroatom replacement on the charge carrier mobility are studied. The results obtained in the simulations of one-dimensional aligned π-stacks of molecular semiconductors are compared with available experimental data for small conjugated benzothiadiazole-cored molecules with thiophene flanks and benzothiadiazole-quaterthiophene-based copolymers.