Intermolecular interactions induced property improvement for clean fracturing fluid by deep eutectic solvents

Fracturing fluid property play a critical role in developing unconventional reservoirs.Deep eutectic solvents(DESs)show fascinating potential for property improvement of clean fracturing fluids(CFFs)due to their low-price,low-toxicity,chemical stability and flexible designability.In this work,DESs were synthesized by mixing hydrogen bond acceptors(HBAs)and a given hydrogen bond donor(HBD)to explore their underlying influence on CFF properties based on the intermolecular interactions.The hydrogen-bonding,van der Waals and electrostatic interactions between DES components and surfactants improved the CFF properties by promoting the arrangement of surfactants at interface and enhancing the micelle network strength.The HBD enhanced the resistance of CFF for Ca^(2+) due to coordination-bonding interaction.The DESs composed of choline chloride(ChCl)and malonic acid show great enhancement for surface,rheology,temperature resistance,salt tolerance,drag reduction,and gel-breaking performance of CFFs.The DESs also improved the gel-breaking CFF-oil interactions,increasing the imbibition efficiencies to 44.2%in 74 h.Adjusting HBAs can effectively strengthen the intermolecular interactions(e.g.,HBA-surfactant and HBD-surfactant interactions)to improve CFF properties.The DESs developed in this study provide a novel strategy to intensify CFF properties.

Weak Intermolecular Interactions for Strengthening Organic Batteries

Organic batteries have attracted a lot of attention due to the advantages of flexibility,light weight,vast resources,low cost,recyclability,and ease to be functionalized through molecular design.The biggest difference between organic materials and inorganic materials is the relatively weak intermolecular interactions in organic materials but strong covalent or ionic bonds in inorganic materials,which is the inherent reason of their different physiochemical and electrochemical characteristics.Therefore,the relatively weak intermolecular interactions can indisputably affect the electrochemical performance of organic batteries significantly.Herein,the intermolecular interactions that are closely related to organic redox-active materials and unique in organic batteries are summarized into three parts:1)between neighbor active molecules,2)between active molecules and the conduction additives,and 3)between active molecules and the binders.We hope this short review can give a distinct viewpoint for better understanding the internal reasons of high-performance batteries and stimulate the deep studies of relatively weak intermolecular interactions for strengthening the performance of organic batteries.

Intermolecular Interactions, Thermodynamic Properties, Detonation Performance, and Sensitivity of TNT/CL-20 Cocrystal Explosive

Intermolecular interactions and properties of TNT（2,4,6-trinitrotoluene）/CL-20（2,4,6,8,10,12-hexanitrohexaazaisowurtzitane） cocrystal were studied by density functional theory（DFT） methods. Binding energy, natural bond orbital（NBO）, and atom in molecules（AIM） analysis were performed to investigate the intermolecular interactions in the cocrystal. Results show that the unconventional CH···O type hydrogen bond plays a key role in forming the cocrystal. The variation tendency of entropy and enthalpy shows that the formation of the cocrystal is an exothermic process and low temperature will be benefit for the assembling of complexes. The calculated detonation velocity of the cocrystal agrees well with the experimental value which is higher than that of the physical mixture of TNT and CL-20. In addition, bond dissociation energies（BDEs） of the weakest trigger bond in TNT/CL-20 complex were calculated and the results show that the TNT/CL-20 complex is thermally stable. Finally, first-principles calculations were performed and analysis of the nitro group Mulliken charge indicates that the cocrystal is less sensitive than pure CL-20.

Intermolecular Interaction of HMX: an Application of ONIOM Methodology

Ab initio calculations at the B3LYP/3-21G^(**), HF/3-21G>^(**) and ONIOM(HF/3-21G^(**): AM1) levels of the theory in combination with counterpoise procedure for BSSE correction were performed on HMX dimers. There exist two O...H intermolecular contacts and the dispersion forces are dominant in the dimers. The corrected binding energies of the dimer are -15.10 and -17.81 kJ/mol at the HF/3-21G^(**) and \{ONIOM(HF/3-21G^(**): AM1) \}levels, respectively. The calculation by the B3LYP method gives irrational corrected binding energies though it produces similar intermolecular distances as those produced by the HF or \{ONIOM\} method. The geometrical parameters, the contact distances and the binding energies demonstrated, for the first time, the validity of the ONIOM method applied in the calculation of the parameters of intermolecular interactions.

Density Functional Theory Studies on the Intermolecular Interactions of Five Aza-calix[6]arene Host with HMX

Five fully optimized structures of complexes between aza-calix[6]arene host monomers（Ma～Me） and complexes（a～e） have been obtained at the B3LYP/6-31G（d） level.Natural bond orbital（NBO） analysis was performed to reveal the origin of the interaction.The intermolecular interaction energy was evaluated with basis set superposition error correction（BSSE） and zero point energy correction（ZPEC）.The B3LYP/6-31G（d） calculations on the five complexes have shown that the greatest interaction（–13.98 kJ/mol） is found in the complex between HMX and hexa-aza-calix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine.The results have indicated that intermolecular interaction energies of aza-calix[6]arenes with substituted group are stronger than those without substituted group,and those with amido are greater than with nitryl.Thus,hexa-azacalix[3]-p-tri-arene[3]-2-amido-1,3,5-tri-azine is rather equal to eliminate HMX from explosive waste water.

Theoretical Study on the Intermolecular Interactions of Tetrazole Dimers

Tetrazole monomers （Ⅰ, Ⅱ） and all of their possible stable dimers （1, 2, 3, 4, 5, 6, 7 and 8） were fully optimized by DFT method at the B3LYP/6-311＋＋G^＊＊ level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable （no imaginary frequencies）. The basis set superposition errors （BSSE） are 2.78, 2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy （ZPE） corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6, 7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of the dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the adjacent N-H…N atoms between submolecules. The charge transfer between two subsystems is very small. Natural bond orbital （NBO） analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities （C^0P）, entropies （S^0T） and thermal corrections to enthalpy （H^0T）, and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously turn into two stable dimers at 298.15 K.

Theoretical Studies on Intermolecular Interactions of 4-Amino-5-nitro-1,2,3-triazole Dimers

Seven optimized configurations and their electronic structures of 4-amino-5-nitro- 1,2,3-triazole dimers on their potential energy surface have been obtained by using density functional theory （DPT） method at the B3LYP/6-311＋＋G＊＊ level. The maximum intermolecular interaction energy is -35.42 kJ/mol via the basis set superposition error-correction （BSSE） and zero point energy-correction （ZPE）. Charge transfers between the two subsystems are small. The vibration analysis of optimized configurations was performed, and the thermodynamic property changes from monomer to dimer have been obtained with the temperature ranging from 200 to 800 K on the basis of statistical thermodynamics. It is found that the hydrogen bonds contribute to the dimers dominantly, and the extent of intermolecular interaction is mainly determined by the hydrogen bonds＇ strength rather than their number. The dimerization processes of Ⅳ, Ⅴand Ⅵ can occur spontaneously at 200 K.

Ab initio Studies on Intermolecular Interaction of Formamide and Hydroxyacetonitrile Dimers

The structures,the binding energies and the thermodynamic properties of formamide and hydroxyacetonitrile(HAN) dimers have been studied by means of the self\|consistent \%ab initio\% Hartree\|Fock and the second\|order Mφller\|Plesset correlation energy correction methods. The counterpoise procedure was used to check the basis set superposition error(BSSE) of the binding energies. There exist cyclic structures in a formamide dimer(Ⅰ),a HAN dimer(Ⅱ) and their heterodimer(Ⅲ). The corrected binding energies for dimers Ⅰ,Ⅱ and Ⅲ are respectively -45.53,-45.83 and -43.89 kJ/mol at the MP2/aug\|cc\|p VDZ//HF/\{aug\|cc\|p VDZ\} level. The change of the Gibbs free energies(Δ\%G\%) in the process of Ⅰ+Ⅱ→2Ⅲ was predicted to be -2.74 kJ/mol at 298.15 K. Dimer Ⅲ can be spontaneously produced in the mixture of formamide and HAN,which is in agreement with the experimental fact that most cyanohydrins are capable of interacting with dipeptide cyclo\|His\|Phe(CHP).

Study of intermolecular interactions in binary mixtures of methyl acrylate with benzene and methyl substituted benzenes at different temperatures:An experimental and theoretical approach

The ultrasonic speeds,u and viscosities,ηof the binary mixtures of methyl acrylate with benzene,toluene,o-xylene,m-xylene,p-xylene,and mesitylene over the whole mole fraction range were measured at six different temperatures and at atmospheric pressure.From the experimental data,the excess isentropic compressibility,κ_(s)^(E),excess ultrasonic speed,u^(E),excess molar isentropic compressibility,K_(s,m)^(E),excess specific impedance,Z^(E)and deviations in viscosity,Δηhave been calculated.The partial molar isentropic compressions,K_(s,m,1) and K_(s,m,2),and excess partial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E) over the whole composition range,partial molar isentropic compressions,K_(s,m,1)^(-)and K_(s,m,2)^(-),and excesspartial molar isentropic compressions,K_(s,m,1)^(-E) and K_(s,m,2)^(-E)of the components at infinite dilution have also been calculated.The results specified the existence of weak interactions between unlike molecules,and these interactions follow the order:benzene>toluene>p-xylene>m-xylene>o-xylene>mesityle ne.The magnitude of interactions was found to be dependent on the number and position of the methyl groups in these aromatic hydrocarbons.

MECHANICAL RELAXATION AND INTERMOLECULAR INTERACTION IN EPOXY RESINS/POLY (ETHYLENE OXIDE) BLENDS CURED WITH PHTHALIC ANHYDRIDE

The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.

The Intermolecular Interaction in Self-Assembled Monolayers on Gold Electrode

The intermolecular interaction in an azobenzene self-assembled monolayers (SAMs) on gold electrode was investigated by controlling the assembling time and using mixed self-assembled techniques, and the variation of apparent electron transfer rate constant (k(s)) of azobenzene SAMs with different molecular packing density is reported.

Theoretical Investigation on Intermolecular Interactions Between HCCF and HCCR(R=F,Cl,Br)

Geometries, interaction energies and electronic properties for four types of dimers（hydrogen bonded, halogen bonded, π-halogen bonded, and ~r-hydrogen bonded） between HCCF and HCCR（R=F, CI, Br） were studied via MP2/6-31 1＋＋G（d,p） ab initio calculation. It is shown that the strength of the zr-hydrogen bonded dimers turns out to be greater than those of the other three types of dimers, with the interaction energies --4.611 kJ/mol for HCCF-HCCF, -4.700 kJ/mol for HCCF-HCCC1, and -4.850 kJ/mol for HCCF-HCCBr respectively at the CCSD（T）/6-311＋＋ G（d,p）//MP2/6-31 1＋＋G（d,p） level. In an effort to understand the nature of the intermolecular interactions prevalent in these dimers, the interaction energies were decomposed into physically distinct energy components with the aid of the symmetry adapted perturbation theory（SAPT）. The dispersion force is found to be the main origin of the intermolecular interactions in hydrogen bonded and halogen bonded dimers. In the π-halogen bonded system, the dispersion is the major bonding force in HCCF-HCCF and HCCF-HCCC1, while the induction energy is the most important component in HCCF-HCCBr. However, both the dispersion and electrostatic energy play a key role in π-hydrogen bonded dimers.

Theoretical Studies on the Intermolecular Interactions of Aza-calix[2]arene[2]-triazines with RDX

Six fully optimized structures of the aza-calix[2]arene[2]-triazines/RDX supramo-lecular complexes have been obtained at the DFT-B3LYP/6-311＋＋G＊＊ level,and the corresponding intermolecular interactions have been investigated using the B3LYP,mPWPW91 and MP2 methods at the 6-311＋＋G＊＊ level,respectively.The natural bond orbital（NBO） and atoms in molecules（AIM） analyses have been performed to reveal the origin of interactions.To our interest,the result indicates that the strongest interaction is up to-22.34 kJ/mol after basis set superposition error（BSSE） and zero point energy（ZPE） correction at the MP2/6-311＋＋G＊＊ level.Furthermore,the intermolecular interactions between aza-calix[2]arene[2]-triazines with the substituted amidos and RDX are stronger than those of other complexes.Thus,the complexes with amidos can be used as the candidates to increase the stability of explosive and eliminate the explosive wastewater.

Role of the Metabolic Minor Components in the Regulation of Intermolecular Interaction

This work presents a study of intermolecular interactions using the model of the antigen antibody interactions of the ABO system. Absence of knowledge in the field of the ABO antigen’s behavior as a biomolecule and the integration of these structures into cascade of metabolic and physiological processes create the conditions, which promote a successful using this new model in the future. Molecular recognition and designing are included into the main catalog of computer methods of research, which is called “in silico”. Using PASS system, we describe the possible biological effects of pyruvate, lactate, antigen determinants A and B. Pharmacological effects and molecular mechanisms of influence on activity of the factors regulating inside and intercellular interactions are predicted for such minor components as pyruvate and lactate. Due to variety of the biological effects, glycoproteins A and B are very perspective to study as biological active connections. The obtained knowledge proves that AB0 antigens, as well as other glycoprotein conjugates are important mediators of intercellular adhesion and participants of signal transmission. Using ABO blood group system as a model helped to describe individual differences of parameters—degree and time of the agglutination beginning of antigen/antibody blood types of the AB0—are revealed.

Covalent intermolecular interaction of the nitric oxide dimer (NO)_2

Covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent character, the result from direct applications of classical simulation methods to the molecular system would be questionable. Here, we analyze the special intermolecular interaction between two NO molecules based on quantum chemical calculation. This weak intermolecular interaction, which is of covalent character, is responsible for the formation of the NO dimer,（NO）2, in its most stable conformation, a cis conformation. The natural bond orbital（NBO） analysis gives an intuitive illustration of the formation of the dimer bonding and antibonding orbitals concomitant with the breaking of the πbonds with bond order 0.5of the monomers. The dimer bonding is counteracted by partially filling the antibonding dimer orbital and the repulsion between those fully or nearly fully occupied nonbonding dimer orbitals that make the dimer binding rather weak. The direct molecular mechanics（MM） calculation with the UFF force fields predicts a trans conformation as the most stable state, which contradicts the result of quantum mechanics（QM）. The lesson from the investigation of this special system is that for the case where intermolecular interaction is of covalent character, a specific modification of the force fields of the molecular simulation method is necessary.

Theory Studies on the Intermolecular Interactions of Urea Nitrate with RDX

Six fully optimized geometries of urea nitrate cation and RDX complexes have been obtained with DFT-B3LYP and MP2 methods at the 6-311＋＋G＊＊ level. The intermolecular interaction energies have been calculated with basis set superposition error （BSSE） and zero point energy （ZPE） correction. The nature of intermolecular interaction has been revealed by the analysis of AIM and NBO. The results indicate that the greatest binding energy of urea nitrate with RDX is –82.47kJ/mol. The O–H…O and N–H…O hydrogen bonds are important intermolecular interactions of urea nitrate cation with RDX, and the origin of hydrogen bonds is the oxygen atom offering its lone-pair electrons to the σ（O-H）＊ or σ（O-H）＊ antibonding orbital. The intermolecular interactions strengthen the N–NO2 bond, leading to the reduced sensitivity of urea nitrate and RDX mixture explosive.

Manipulating intermolecular interactions for ultralong organic phosphorescence

Ultralong organic phosphorescence(UOP)materials have received considerable attention in the field of organic optoelectronics due to their long lifetime,high exciton utilization,large Stokes shift,and so on.Great advancements have been achieved through manipulating intermolecular interactions for high-performance UOP materials in recent years.This review will discuss the influence of various intermolecular interactions,includingπ-πinteractions,n-πinteractions,halogen bonding,hydrogen bonding,coordinative bonding,and ionic bonding on phosphorescent properties at room temperature,respectively.We summarize the rule of manipulating intermolecular interactions for UOP materials with superior phosphorescent properties.This review will provide a guideline for developing new UOP materials with superior phosphorescent properties for potential applications in organic electronics and bioelectronics.

Enhancing the Intermolecular Interactions of Ladder-Type Heteroheptacene-Based Nonfullerene Acceptors for Efficient Polymer Solar Cells by Incorporating Asymmetric Side Chains

Asymmetric nonfullerene acceptors(NFAs)possess larger dipole moments and stronger intermolecular bonding energy than their symmetric counterparts thereby making them promising candidates for high-performance polymer solar cells(PSCs).Herein,we report twoefficient acceptor–donor–acceptor(A–D–A)type NFAs(M14 and M18)with asymmetric side chains that show enhanced intermolecular interactions compared with their corresponding counterparts(M17 and M19)based on symmetric side chains.Furthermore,M14 and M18 exhibit elevated lowest unoccupiedmolecular orbitals and smallerπ–πstacking distances in comparison with M17 and M19,respectively.In combination with the benchmark polymer donor of PM6,the PM6:M14 blend affords superior charge transport properties,and more importantly,an increased power conversion efficiency(PCE)of 15.49%in comparison with the M17-based counterpart(13.01%PCE).Similarly,the asymmetric M18-based blend also shows a higher PCE of 13.00%than the M19-based blend(11.55%).Through further interface engineering,the bestperforming M14-based device delivers an enhanced PCE of 16.46%,which represents a record value among all asymmetric A–D–A type NFAs.Our results provide new insights into the design of asymmetric NFAs with enhanced intermolecular interactions for highperformance PSCs.

Tuning the intermolecular interaction of A_(2)-A_(1)-D-A_(1)-A_(2) type non-fullerene acceptors by substituent engineering for organic solar cells with ultrahigh V_(OC) of ~1.2 V

For non-fullerene acceptors(NFAs)with linear A_(2)-A_(1)-D-A_(1)-A_(2) backbone,there are three kinds of possible intermolecular interaction,A_(1)-A_(1),A_(1)-A_(2) and A_(2)-A_(2) stacking.Hence,it is a huge challenge to control this interaction and investigate the effect of intermolecular stacking model on the photovoltaic performance.Here,we adopt a feasible strategy,by utilizing different substituent groups on terminal A2 unit of dicyanomethylene rhodanine(RCN),to modulate this stacking model.According to theoretical calculation results,the molecule BTA3 with ethyl substituent packs via heterogeneous interaction between A_(2) and A_(1) unit in neighboring molecules.Surprisingly,the benzyl group can effectively transform the aggregation of BTA5 into homogeneous packing of A_(2)-A_(2) model,which might be driven by the strong interaction between benzyl and A1(benzotriazole)unit.However,different with benzyl,phenyl end group impedes the intermolecular interaction of BTA4 due to the large steric hindrance.When using a BTA-based D-π-A polymer J52-F as donor according to“Same-A-Strategy”,BTA3-5 could achieve ultrahigh open-circuit voltage(VOC)of 1.17–1.21 V.Finally,BTA5 with benzyl groups realized an improved power conversion efficiency(PCE)of 11.27%,obviously higher than that of BTA3(PCE=9.04%)and BTA4(PCE=5.61%).It is also worth noting that the same trend can be found when using other four classic p-type polymers of P3HT,PTB7,PTB7-Th and PBDB-T.This work not only investigates the intermolecular interaction of A_(2)-A_(1)-D-A_(1)-A_(2) type NFAs for the first time,but also provides a straightforward and universal method to change the interaction model and improve the photovoltaic performance.

Theoretical Study on Intermolecular Interactions and Thermodynamic Properties of Dimethylnitroamine Clusters

Ab initio SCF and Moller-Plesset correlation correction methods incombination with counterpoise procedure for BSSE correction have been applied to the theroeticalstudying of dimethylnitroamine and its dimers and trimers. Three optimized stable dimers and twotrimers have been obtained. The corrected binding energies of the most stable dimer and trimer werepredicted to be - 24.68 kJ/mol and - 47.27 kJ/mol, respectively at the MP2/6-31G ~*//HF/6-31G~*level. The proportion of correlated interaction energies to their total interaction energies for allclusters was at least 29.3 percent, and the BSSE of ΔE(MP2) was at least 10.0 kJ/mol. Dispersionand/ or electrostatic force were dominant in all clusters. There exist cooperative effects in boththe chain and the cyclic trimers. The vibrational frequencies associated with N―O stretches or wagsexhibit slight red shifts, but the modes associated with the motion of hydrogen atoms of the methylgroup show somewhat blue shifts with respect to those of monomer. Thermodynamic properties ofdimethylnitroamine and its clusters at different temperatures have been calculated on the basis ofvibrational analyses. The changes of the Gibbs free energies for the aggregation from monomer to themost stable dimer and trimer were predicted to be 14.37 kJ/mol and 30.40 kJ/mol, respectively, at 1atm and 298.15 K.