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Non-covalent Interaction
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Non-covalent Interaction

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Materials Science".

Deadline for manuscript submissions: closed (15 November 2022) | Viewed by 32896

Special Issue Editors

Dr. Attila Bende

E-Mail Website
Guest Editor
National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street, No. 67-103, 400283 Cluj-Napoca, Romania
Interests: intermolecular interactions; self-assembled supramolecular systems; laser-molecule interaction; molecular excited states; biopolymers
Special Issues, Collections and Topics in MDPI journals
Dr. Mihai V. Putz

E-Mail Website
Guest Editor
1. Laboratory of Structural and Computational Physical-Chemistry for Nanosciences and QSAR, Biology-Chemistry Department, West University of Timisoara, Str. Pestalozzi 16, 300115 Timisoara, Romania
2. Laboratory of Renewable Energies-Photovoltaics, R&D National Institute for Electrochemistry and Condensed Matter–INCEMC–Timisoara, Str. Dr. Aurel Podeanu 144, 300569 Timișoara, Romania
Interests: quantum physical chemistry; nanochemistry; reactivity indices and principles; electronegativity; density functional theory; path integrals; enzyme kinetics; QSAR; epistemology and philosophy of science
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Although the field of research on noncovalent interactions involves long periods of scientific research and operates with mature theoretical models, we believe that there are special areas that we still consider worthwhile to study in depth. Of these, it is important to mention metal–lone pair electron orbital interactions in metal–organic complexes, the halogen bond formed between metal halides and electron rich organic units, intermolecular interaction between molecular fragments in electronic excited state configuration, or long-range interaction that includes higher-order nonadditive many-body Van der Waals (vdW) energy contributions. Although there are well-developed theoretical models—which can accurately describe the nature of intermolecular interactions, most of them based on wavefunction methods—there are still cases where, for example, density-based methods such as DFT (density functional theory) cannot be effectively handled using this theory. In this regard, there is still a need to develop efficient exchange correlation functionals that can accurately reproduce the results obtained with high-level electron correlation theories. At the same time, it is important to mention recently developed methods such as the machine learning technique, which we believe can be effectively used to more accurately parameterize the various intermolecular interaction potentials used in classical molecular dynamic studies.

This Special Issue is intended to provide a common platform for experimental and modeling science in order to gain a more comprehensive picture of these noncovalent interactions. Both original research articles and reviews in the fields of molecular self-assembly, crystal design, adsorption of ensemble molecules on a surface or interface and intermolecular interaction theories are welcome.

Dr. Attila Bende
Prof. Dr. Mihai V. Putz
Guest Editors

Manuscript Submission Information

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Keywords

  • noncovalent interactions
  • high-order electron correlation
  • density functional theory
  • halogen bond
  • machine learning techniques
  • molecular self-assembly
  • metal-organic complex
  • electronic excited state
  • surface adsorption

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13 pages, 2824 KiB  
Article
Intermolecular-Type Conical Intersections in Benzene Dimer
by Attila Bende and Alex-Adrian Farcaş
Int. J. Mol. Sci. 2023, 24(3), 2906; https://doi.org/10.3390/ijms24032906 - 02 Feb 2023
Cited by 4 | Viewed by 1705
Abstract
The equilibrium and conical intersection geometries of the benzene dimer were computed in the framework of the conventional, linear-response time-dependent and spin-flipped time-dependent density functional theories (known as DFT, TDDFT and SF-TDDFT) as well as using the multiconfigurational complete active space self-consistent field [...] Read more.
The equilibrium and conical intersection geometries of the benzene dimer were computed in the framework of the conventional, linear-response time-dependent and spin-flipped time-dependent density functional theories (known as DFT, TDDFT and SF-TDDFT) as well as using the multiconfigurational complete active space self-consistent field (CASSCF) method considering the minimally augmented def2-TZVPP and the 6–31G(d,p) basis sets. It was found that the stacking distance between the benzene monomers decreases by about 0.5 Å in the first electronic excited state, due to the stronger intermolecular interaction energy, bringing the two monomers closer together. Intermolecular-type conical intersection (CI) geometries can be formed between the two benzene molecules, when (i) both monomer rings show planar deformation and (ii) weaker (approximately 1.6–1.8 Å long) C–C bonds are formed between the two monomers, with parallel and antiparallel orientation with respect to the monomer. These intermolecular-type CIs look energetically more favorable than dimeric CIs containing only one deformed monomer. The validity of the dimer-type CI geometries obtained by SF-TDDFT was confirmed by the CASSCF method. The nudged elastic band method used for finding the optimal relaxation path has confirmed both the accessibility of these intermolecular-type CIs and the possibility of the radiationless deactivation of the electronic excited states through these CI geometries. Although not as energetically favorable as the previous two CI geometries, there are other CI geometries characterized by the relative rotation of monomers at different angles around a vertical C–C axis. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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14 pages, 2128 KiB  
Article
A Cost Effective Scheme for the Highly Accurate Description of Intermolecular Binding in Large Complexes
by Jiří Czernek, Jiří Brus and Vladimíra Czerneková
Int. J. Mol. Sci. 2022, 23(24), 15773; https://doi.org/10.3390/ijms232415773 - 12 Dec 2022
Cited by 6 | Viewed by 1858
Abstract
There has been a growing interest in quantitative predictions of the intermolecular binding energy of large complexes. One of the most important quantum chemical techniques capable of such predictions is the domain-based local pair natural orbital (DLPNO) scheme for the coupled cluster theory [...] Read more.
There has been a growing interest in quantitative predictions of the intermolecular binding energy of large complexes. One of the most important quantum chemical techniques capable of such predictions is the domain-based local pair natural orbital (DLPNO) scheme for the coupled cluster theory with singles, doubles, and iterative triples [CCSD(T)], whose results are extrapolated to the complete basis set (CBS) limit. Here, the DLPNO-based focal-point method is devised with the aim of obtaining CBS-extrapolated values that are very close to their canonical CCSD(T)/CBS counterparts, and thus may serve for routinely checking a performance of less expensive computational methods, for example, those based on the density-functional theory (DFT). The efficacy of this method is demonstrated for several sets of noncovalent complexes with varying amounts of the electrostatics, induction, and dispersion contributions to binding (as revealed by accurate DFT-based symmetry-adapted perturbation theory (SAPT) calculations). It is shown that when applied to dimeric models of poly(3-hydroxybutyrate) chains in its two polymorphic forms, the DLPNO-CCSD(T) and DFT-SAPT computational schemes agree to within about 2 kJ/mol of an absolute value of the interaction energy. These computational schemes thus should be useful for a reliable description of factors leading to the enthalpic stabilization of extended systems. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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12 pages, 3350 KiB  
Article
Robust Supramolecular Dimers Derived from Benzylic-Substituted 1,2,4-Selenodiazolium Salts Featuring Selenium⋯π Chalcogen Bonding
by Alexander A. Sapronov, Alexey A. Artemjev, Gleb M. Burkin, Victor N. Khrustalev, Alexey S. Kubasov, Valentine G. Nenajdenko, Rosa M. Gomila, Antonio Frontera, Andreii S. Kritchenkov and Alexander G. Tskhovrebov
Int. J. Mol. Sci. 2022, 23(23), 14973; https://doi.org/10.3390/ijms232314973 - 29 Nov 2022
Cited by 8 | Viewed by 1979
Abstract
The series of benzylic-substituted 1,2,4-selenodiazolium salts were prepared via cyclization reaction between 2-pyridylselenyl chlorides and nitriles and fully characterized. Substitution of the Cl anion by weakly binding anions promoted the formation supramolecular dimers featuring four center Se2N2 chalcogen bonding and [...] Read more.
The series of benzylic-substituted 1,2,4-selenodiazolium salts were prepared via cyclization reaction between 2-pyridylselenyl chlorides and nitriles and fully characterized. Substitution of the Cl anion by weakly binding anions promoted the formation supramolecular dimers featuring four center Se2N2 chalcogen bonding and two antiparallel selenium⋯π interactions. Chalcogen bonding interactions were studied using density functional theory calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of atoms-in-molecules (QTAIM), and the noncovalent interaction (NCI) plot. The investigations revealed fundamental role of the selenium⋯π contacts that are stronger than the Se⋯N interactions in supramolecular dimers. Importantly, described herein, the benzylic substitution approach can be utilized for reliable supramolecular dimerization of selenodiazolium cations in the solid state, which can be employed in supramolecular engineering. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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18 pages, 3235 KiB  
Article
New O- and N-N-Bridging Complexes of Tc(V), the Role of the Nitrogen Atom Position in Aromatic Rings: Reaction Mechanism, Spectroscopy, DTA, XRD and Hirshfeld Surface Analysis
by Anton Petrovich Novikov and Mikhail Alexandrovich Volkov
Int. J. Mol. Sci. 2022, 23(22), 14034; https://doi.org/10.3390/ijms232214034 - 14 Nov 2022
Cited by 5 | Viewed by 1733
Abstract
In this work, O- and N-N-bridging complexes of technetium (V), previously known only for rhenium, were obtained for the first time. Tc(V) complexes with pyridazine (pyd), 1,2,4-triazole (trz), 3,5-dimethylpyrazole (dmpz) and pyrimidine (pyr) were obtained. In three complexes [{TcOCl2}2(μ-O)(μ-pyd) [...] Read more.
In this work, O- and N-N-bridging complexes of technetium (V), previously known only for rhenium, were obtained for the first time. Tc(V) complexes with pyridazine (pyd), 1,2,4-triazole (trz), 3,5-dimethylpyrazole (dmpz) and pyrimidine (pyr) were obtained. In three complexes [{TcOCl2}2(μ-O)(μ-pyd)2], [{TcOCl2}2(μ-O)(μ-trz)2]·Htrz·Cl and [{TcO(dmpz)4}(μ-O)(TcOCl4)] two technetium atoms are linked by a Tc-O-Tc bond, and in the first two, Tc atoms are additionally linked by a Tc-N-N-Tc bond through the nitrogen atoms of the aromatic rings. We determined the role of nitrogen atom position in the aromatic ring and the presence of substituents on the formation of such complexes. For the first time, a reaction mechanism for the formation of such complexes was proposed. This article details the crystal structures of four new compounds. The work describes in detail the coordination of Tc atoms in the obtained structures and the regularities of the formation of crystal packings. The spectroscopic properties of the obtained compounds and their mother solutions were studied. The decomposition temperatures of the described complexes were determined. An assumption was made about the oligomerization of three-bridged complexes based on the results of mass spectrometry. Through the analysis of non-valent interactions in the structures, π-stacking, halogen-π and CH-π interactions were found. An analysis of the Hirshfeld surface for [{TcOCl2}2(μ-O)(μ-pyd)2], [{TcOCl2}2(μ-O)(μ-trz)2] and their rhenium analogues showed that the main contribution to the crystalline packing is made by interactions of the type Hal···H/H···Hal (45.4–48.9%), H···H (10.2–15.8%), and O···H/H···O (9.4–16.5%). Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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8 pages, 262 KiB  
Article
Reliability of Computing van der Waals Bond Lengths of Some Rare Gas Diatomics
by Yi-Liang Zhang and Bin Li
Int. J. Mol. Sci. 2022, 23(22), 13944; https://doi.org/10.3390/ijms232213944 - 11 Nov 2022
Viewed by 814
Abstract
When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 [...] Read more.
When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d′f,3p′d), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ). Full article
(This article belongs to the Special Issue Non-covalent Interaction)
17 pages, 3262 KiB  
Article
Effects of Lewis Basicity and Acidity on σ-Hole Interactions in Carbon-Bearing Complexes: A Comparative Ab Initio Study
by Mahmoud A. A. Ibrahim, Mohammed N. I. Shehata, Al-shimaa S. M. Rady, Hassan A. A. Abuelliel, Heba S. M. Abd Elhafez, Ahmed M. Shawky, Hesham Farouk Oraby, Tamer H. A. Hasanin, Mahmoud E. S. Soliman and Nayra A. M. Moussa
Int. J. Mol. Sci. 2022, 23(21), 13023; https://doi.org/10.3390/ijms232113023 - 27 Oct 2022
Cited by 3 | Viewed by 1431
Abstract
The effects of Lewis basicity and acidity on σ-hole interactions were investigated using two sets of carbon-containing complexes. In Set I, the effect of Lewis basicity was studied by substituting the X3/X atom(s) of the NC-C6H2-X3 [...] Read more.
The effects of Lewis basicity and acidity on σ-hole interactions were investigated using two sets of carbon-containing complexes. In Set I, the effect of Lewis basicity was studied by substituting the X3/X atom(s) of the NC-C6H2-X3 and NCX Lewis bases (LB) with F, Cl, Br, or I. In Set II, the W-C-F3 and F-C-X3 (where X and W = F, Cl, Br, and I) molecules were utilized as Lewis acid (LA) centers. Concerning the Lewis basicity effect, higher negative interaction energies (Eint) were observed for the F-C-F3∙∙∙NC-C6H2-X3 complexes compared with the F-C-F3∙∙∙NCX analogs. Moreover, significant Eint was recorded for Set I complexes, along with decreasing the electron-withdrawing power of the X3/X atom(s). Among Set I complexes, the highest negative Eint was ascribed to the F-C-F3∙∙∙NC-C6H2-I3 complex with a value of −1.23 kcal/mol. For Set II complexes, Eint values of F-C-X3 bearing complexes were noted within the −1.05 to −2.08 kcal/mol scope, while they ranged from −0.82 to −1.20 kcal/mol for the W-C-F3 analogs. However, Vs,max quantities exhibited higher values in the case of W-C-F3 molecules compared with F-C-X3; preferable negative Eint were ascribed to the F-C-X3 bearing complexes. These findings were delineated as a consequence of the promoted contributions of the X3 substituents. Dispersion forces (Edisp) were identified as the dominant forces for these interactions. The obtained results provide a foundation for fields such as crystal engineering and supramolecular chemistry studies that focus on understanding the characteristics of carbon-bearing complexes. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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16 pages, 8635 KiB  
Article
Non-Covalent Interactions in the Crystal Structures of Perbrominated Sulfonium Derivatives of the closo-Decaborate Anion
by Aleksei V. Golubev, Alexey S. Kubasov, Alexander Yu. Bykov, Andrey P. Zhdanov, Grigorii A. Buzanov, Alexander A. Korlyukov, Konstantin Yu. Zhizhin and Nikolay T. Kuznetsov
Int. J. Mol. Sci. 2022, 23(19), 12022; https://doi.org/10.3390/ijms231912022 - 10 Oct 2022
Viewed by 1170
Abstract
A new series of compounds based on perbrominated disubstituted sulfonium derivatives of the closo-decaborate anion (n-Bu4N)[2-B10Br9SR2] (R = n-Pr, i-Pr, n-Bu, n-C8H17, n-C [...] Read more.
A new series of compounds based on perbrominated disubstituted sulfonium derivatives of the closo-decaborate anion (n-Bu4N)[2-B10Br9SR2] (R = n-Pr, i-Pr, n-Bu, n-C8H17, n-C12H25, n-C18H37) was obtained, characterised by modern physicochemical methods of analysis. According to the results of an X-ray diffraction study, some of the anions and solvate molecules were disordered. The cations (n-Bu4N)+ and anions [2-B10Br9SR2]− were associated via C-H…Br and H…H contacts. In addition, Br…Br interactions between anions were revealed. The role of these contacts was analysed in terms of Hirshfeld surface analysis, QTAIM theory and the NCI method using quantum chemical calculations. An increase in the size of the alkyl R moiety led to significant strengthening of the total energy of H…H interactions. In the case of R = -n-C18H37, a parallel mutual orientation of alkyl moieties was established that was similar to the packing of salts of fatty acids. The nature of C-H…Br and Br…Br interionic interactions was found to be attractive, in contrast to the repulsive nature of intermolecular Br…Br interactions. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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10 pages, 3795 KiB  
Article
Size-Dependent Spontaneous Separation of Colloidal Particles in Sub-Microliter Suspension by Cations
by Shiqi Sheng, Haijun Yang, Yongshun Song, Ruoyang Chen, Shanshan Liang and Haiping Fang
Int. J. Mol. Sci. 2022, 23(15), 8055; https://doi.org/10.3390/ijms23158055 - 22 Jul 2022
Cited by 2 | Viewed by 1414
Abstract
Great efforts have been made to separate micro/nanoparticles in small-volume specimens, but it is a challenge to achieve the simple, maneuverable and low-cost separation of sub-microliter suspension with large separation distances. By simply adding trace amounts of cations (Mg2+/Ca2+/Na [...] Read more.
Great efforts have been made to separate micro/nanoparticles in small-volume specimens, but it is a challenge to achieve the simple, maneuverable and low-cost separation of sub-microliter suspension with large separation distances. By simply adding trace amounts of cations (Mg2+/Ca2+/Na+), we experimentally achieved the size-dependent spontaneous separation of colloidal particles in an evaporating droplet with a volume down to 0.2 μL. The separation distance was at a millimeter level, benefiting the subsequent processing of the specimen. Within only three separating cycles, the mass ratio between particles with diameters of 1.0 μm and 0.1 μm can be effectively increased to 13 times of its initial value. A theoretical analysis indicates that this spontaneous separation is attributed to the size-dependent adsorption between the colloidal particles and the aromatic substrate due to the strong hydrated cation-π interactions. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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16 pages, 4125 KiB  
Article
Molecular Dynamics Simulation of Association Processes in Aqueous Solutions of Maleate Salts of Drug-like Compounds: The Role of Counterion
by Mikhail V. Vener, Denis E. Makhrov, Alexander P. Voronin and Daria R. Shalafan
Int. J. Mol. Sci. 2022, 23(11), 6302; https://doi.org/10.3390/ijms23116302 - 04 Jun 2022
Cited by 6 | Viewed by 2343
Abstract
The study of the formation of microstructures during the interaction of a protonated drug-like compound (API) with a maleic acid monoanion sheds light on the assembly processes in an aqueous solution at the molecular level. Molecular dynamics (MD) simulations coupled with density functional [...] Read more.
The study of the formation of microstructures during the interaction of a protonated drug-like compound (API) with a maleic acid monoanion sheds light on the assembly processes in an aqueous solution at the molecular level. Molecular dynamics (MD) simulations coupled with density functional theory (DFT) calculations made it possible to find initial hydrogen bonding motifs during the assembly process, leading to the formation of heterodimers and trimers. The process of trimer formation [protonated API—maleic acid monoanion—protonated API] proceeds through the formation of three intermolecular H-bonds by the CO2− group of the maleic acid monoanion in both systems. The total enthalpy/energy of these H-bonds is more than 70 kJ/mol. Thus, the maleic acid monoanion plays a key role in the processes of association in aqueous solution, and the interaction of the maleic acid monoanion with API is more preferable than the interaction of API molecules with each other. DFT computations in the discrete continuum approximation reveal the spectral features of heterodimers and trimers, and the ATR-IR spectra confirmed these findings. MD simulations followed by DFT calculations made it possible to describe the initial stages of the formation of pharmaceutical cocrystals in an aqueous solution. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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22 pages, 23403 KiB  
Article
Strong Hydrogen Bonds in Acetylenedicarboxylic Acid Dihydrate
by Urban Novak, Amalija Golobič, Natalija Klančnik, Vlasta Mohaček-Grošev, Jernej Stare and Jože Grdadolnik
Int. J. Mol. Sci. 2022, 23(11), 6164; https://doi.org/10.3390/ijms23116164 - 31 May 2022
Viewed by 1542
Abstract
Acetylenedicarboxylic acid dihydrate (ADAD) represents a complex with strong hydrogen bonding between the carboxylic OH and the water molecule. An X-ray re-examination of the ADAD crystal structure confirms the O…O distance of the short hydrogen bonds, and clearly shows different bond [...] Read more.
Acetylenedicarboxylic acid dihydrate (ADAD) represents a complex with strong hydrogen bonding between the carboxylic OH and the water molecule. An X-ray re-examination of the ADAD crystal structure confirms the O…O distance of the short hydrogen bonds, and clearly shows different bond lengths between the two oxygen atoms with respect to the carbon atom in the carboxyl group, indicating a neutral structure for the complex. The neutral structure was also confirmed by vibrational spectroscopy, as no proton transfer was observed. The diffraction studies also revealed two polymorph modifications: room temperature (α) and low temperature (β), with a phase transition at approximately 4.9 °C. The calculated vibrational spectra are in satisfactory agreement with the experimental spectra. A comparison of the structure and the vibrational spectra between the ADAD and the oxalic acid dihydrate reveals some interesting details. The crystal structures of both crystal hydrates are almost identical; only the O…O distances of the strongest hydrogen bonds differ by 0.08 Å. Although it was expected that a larger O…O spacing in the ADAD crystal may significantly change the infrared and Raman spectra, especially for the frequency and the shape of the acidic OH stretching vibration, both the shape and frequency are almost identical, with all subpeaks topped on the broad OH stretching vibration. The O…O distance dependent are only in- and out-of-plane OH deformations modes. The presence of polarons due to the ionized defects was not observed in the vibrational spectra of ADAD. Therefore, the origin of the broad OH band shape was explained in a similar way to the acid dimers. The anharmonicity of a potential enhances the coupling of the OH stretching with the low-frequency hydrogen bond stretching, which, in addition to the Fermi resonance, structures the band shape of the OH stretching. The fine structure found as a superposition of a broad OH stretching is attributed to Davydov coupling. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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14 pages, 67866 KiB  
Article
Mechanical Properties of TC11 Titanium Alloy and Graphene Nanoplatelets/TC11 Composites Prepared by Selective Laser Melting
by Bingxian Ou, Lixin Lu, Qinsheng Wang, Qing He, YiLin Xie and Junxia Yan
Int. J. Mol. Sci. 2022, 23(11), 6134; https://doi.org/10.3390/ijms23116134 - 30 May 2022
Cited by 4 | Viewed by 1659
Abstract
Titanium matrix composites (TMCs) with excellent mechanical properties, reinforced by graphene, is deemed the lightweight and high strength structural materials. In this study, TC11 titanium alloy powder and graphene nanosheets (GNPs) were used as raw materials, and the composite powder with good uniformity [...] Read more.
Titanium matrix composites (TMCs) with excellent mechanical properties, reinforced by graphene, is deemed the lightweight and high strength structural materials. In this study, TC11 titanium alloy powder and graphene nanosheets (GNPs) were used as raw materials, and the composite powder with good uniformity and fluidity was obtained through non-interventional homogeneous mixing by a planetary mixer. The microstructure and mechanical properties of the GNPs-TC11 composites and TC11 alloy were compared. The results showed that the microstructure of TC11 and the composites was acicular martensite α’ phase under the process parameters of 280 W laser power, 1200 mm/s scanning speed, and 0.1 mm hatch spacing. The GNPs in addition, in the composites, reduced the acicular martensite particle size and expanded the proportion of low-angle grain boundaries. The tensile strength and percentage elongation after the fracture of the TC11 titanium alloy were 1265 MPa and 4.3%, respectively. Because of addition of the GNPs, the strength and percentage elongation after the fracture of the composite increased to 1384 MPa and 8.1%, respectively, at a GNPs mass content of 0.2%. The enhancement of mechanical properties can be attributed to grain refinement, dislocation strengthening, Orowan strengthening, and load transfer strengthening. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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8 pages, 2750 KiB  
Communication
Supramolecular Hydrogen Bonding Assembly from Non-Coplanar Aromatic Tetra-1H-Pyrazoles with Crystallization-Induced Emission (CIE)
by Ji Wang, Li-Rong Zhao, Jin Tong, Yan-Min Yu, Xia-Yan Wang and Shu-Yan Yu
Int. J. Mol. Sci. 2022, 23(8), 4206; https://doi.org/10.3390/ijms23084206 - 11 Apr 2022
Cited by 8 | Viewed by 1657
Abstract
Here, we report a design strategy for constructing supramolecular organic frameworks by introducing 1H-pyrazole groups to aromatic cores as non-coplanar molecules to form diverse supramolecular assemblies through multiple 1H-pyrazole [N−H···N] hydrogen bonds as well as other weak interactions. The new supramolecular [...] Read more.
Here, we report a design strategy for constructing supramolecular organic frameworks by introducing 1H-pyrazole groups to aromatic cores as non-coplanar molecules to form diverse supramolecular assemblies through multiple 1H-pyrazole [N−H···N] hydrogen bonds as well as other weak interactions. The new supramolecular organic frameworks displayed interesting crystallization-induced emission (CIE) behavior. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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9 pages, 1386 KiB  
Article
Enhancement of the Water Affinity of Histidine by Zinc and Copper Ions
by Yongshun Song, Jing Zhan, Minyue Li, Hongwei Zhao, Guosheng Shi, Minghong Wu and Haiping Fang
Int. J. Mol. Sci. 2022, 23(7), 3957; https://doi.org/10.3390/ijms23073957 - 02 Apr 2022
Cited by 3 | Viewed by 1684
Abstract
Histidine (His) is widely involved in the structure and function of biomolecules. Transition-metal ions, such as Zn2+ and Cu2+, widely exist in biological environments, and they are crucial to many life-sustaining physiological processes. Herein, by employing density function calculations, we [...] Read more.
Histidine (His) is widely involved in the structure and function of biomolecules. Transition-metal ions, such as Zn2+ and Cu2+, widely exist in biological environments, and they are crucial to many life-sustaining physiological processes. Herein, by employing density function calculations, we theoretically show that the water affinity of His can be enhanced by the strong cation–π interaction between His and Zn2+ and Cu2+. Further, the solubility of His is experimentally demonstrated to be greatly enhanced in ZnCl2 and CuCl2 solutions. The existence of cation–π interaction is demonstrated by fluorescence, ultraviolet (UV) spectroscopy and nuclear magnetic resonance (NMR) experiments. These findings are of great importance for the bioavailability of aromatic drugs and provide new insight for understanding the physiological functions of transition metal ions. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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17 pages, 4968 KiB  
Article
Type I–IV Halogen⋯Halogen Interactions: A Comparative Theoretical Study in Halobenzene⋯Halobenzene Homodimers
by Mahmoud A. A. Ibrahim, Rehab R. A. Saeed, Mohammed N. I. Shehata, Muhammad Naeem Ahmed, Ahmed M. Shawky, Manal M. Khowdiary, Eslam B. Elkaeed, Mahmoud E. S. Soliman and Nayra A. M. Moussa
Int. J. Mol. Sci. 2022, 23(6), 3114; https://doi.org/10.3390/ijms23063114 - 14 Mar 2022
Cited by 22 | Viewed by 2622
Abstract
In the current study, unexplored type IV halogen⋯halogen interaction was thoroughly elucidated, for the first time, and compared to the well-established types I–III interactions by means of the second-order Møller–Plesset (MP2) method. For this aim, the halobenzene⋯halobenzene homodimers (where halogen = Cl, Br, [...] Read more.
In the current study, unexplored type IV halogen⋯halogen interaction was thoroughly elucidated, for the first time, and compared to the well-established types I–III interactions by means of the second-order Møller–Plesset (MP2) method. For this aim, the halobenzene⋯halobenzene homodimers (where halogen = Cl, Br, and I) were designed into four different types, parodying the considered interactions. From the energetic perspective, the preference of scouted homodimers was ascribed to type II interactions (i.e., highest binding energy), whereas the lowest binding energies were discerned in type III interactions. Generally, binding energies of the studied interactions were observed to decline with the decrease in the σ-hole size in the order, C6H5I⋯IC6H5 > C6H5Br⋯BrC6H5 > C6H5Cl⋯ClC6H5 homodimers and the reverse was noticed in the case of type IV interactions. Such peculiar observations were relevant to the ample contributions of negative-belt⋯negative-belt interactions within the C6H5Cl⋯ClC6H5 homodimer. Further, type IV torsional trans → cis interconversion of C6H5X⋯XC6H5 homodimers was investigated to quantify the π⋯π contributions into the total binding energies. Evidently, the energetic features illustrated the amelioration of the considered homodimers (i.e., more negative binding energy) along the prolonged scope of torsional trans → cis interconversion. In turn, these findings outlined the efficiency of the cis configuration over the trans analog. Generally, symmetry-adapted perturbation theory-based energy decomposition analysis (SAPT-EDA) demonstrated the predominance of all the scouted homodimers by the dispersion forces. The obtained results would be beneficial for the omnipresent studies relevant to the applications of halogen bonds in the fields of materials science and crystal engineering. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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22 pages, 2118 KiB  
Review
Membrane Internalization Mechanisms and Design Strategies of Arginine-Rich Cell-Penetrating Peptides
by Minglu Hao, Lei Zhang and Pu Chen
Int. J. Mol. Sci. 2022, 23(16), 9038; https://doi.org/10.3390/ijms23169038 - 12 Aug 2022
Cited by 31 | Viewed by 3855
Abstract
Cell-penetrating peptides (CPPs) have been discovered to deliver chemical drugs, nucleic acids, and macromolecules to permeate cell membranes, creating a novel route for exogenous substances to enter cells. Up until now, various sequence structures and fundamental action mechanisms of CPPs have been established. [...] Read more.
Cell-penetrating peptides (CPPs) have been discovered to deliver chemical drugs, nucleic acids, and macromolecules to permeate cell membranes, creating a novel route for exogenous substances to enter cells. Up until now, various sequence structures and fundamental action mechanisms of CPPs have been established. Among them, arginine-rich peptides with unique cell penetration properties have attracted substantial scientific attention. Due to the positively charged essential amino acids of the arginine-rich peptides, they can interact with negatively charged drug molecules and cell membranes through non-covalent interaction, including electrostatic interactions. Significantly, the sequence design and the penetrating mechanisms are critical. In this brief synopsis, we summarize the transmembrane processes and mechanisms of arginine-rich peptides; and outline the relationship between the function of arginine-rich peptides and the number of arginine residues, arginine optical isomers, primary sequence, secondary and ternary structures, etc. Taking advantage of the penetration ability, biomedical applications of arginine-rich peptides have been refreshed, including drug/RNA delivery systems, biosensors, and blood-brain barrier (BBB) penetration. Understanding the membrane internalization mechanisms and design strategies of CPPs will expand their potential applications in clinical trials. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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30 pages, 12294 KiB  
Review
Non-Covalent Interaction on the Self-Healing of Mechanical Properties in Supramolecular Polymers
by Kwanchai Buaksuntear, Phakamat Limarun, Supitta Suethao and Wirasak Smitthipong
Int. J. Mol. Sci. 2022, 23(13), 6902; https://doi.org/10.3390/ijms23136902 - 21 Jun 2022
Cited by 17 | Viewed by 3590
Abstract
Supramolecular polymers are widely utilized and applied in self-assembly or self-healing materials, which can be repaired when damaged. Normally, the healing process is classified into two types, including extrinsic and intrinsic self-healable materials. Therefore, the aim of this work is to review the [...] Read more.
Supramolecular polymers are widely utilized and applied in self-assembly or self-healing materials, which can be repaired when damaged. Normally, the healing process is classified into two types, including extrinsic and intrinsic self-healable materials. Therefore, the aim of this work is to review the intrinsic self-healing strategy based on supramolecular interaction or non-covalent interaction and molecular recognition to obtain the improvement of mechanical properties. In this review, we introduce the main background of non-covalent interaction, which consists of the metal–ligand coordination, hydrogen bonding, π–π interaction, electrostatic interaction, dipole–dipole interaction, and host–guest interactions, respectively. From the perspective of mechanical properties, these interactions act as transient crosslinking points to both prevent and repair the broken polymer chains. For material utilization in terms of self-healing products, this knowledge can be applied and developed to increase the lifetime of the products, causing rapid healing and reducing accidents and maintenance costs. Therefore, the self-healing materials using supramolecular polymers or non-covalent interaction provides a novel strategy to enhance the mechanical properties of materials causing the extended cycling lifetime of products before replacement with a new one. Full article
(This article belongs to the Special Issue Non-covalent Interaction)
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