1
|
Díaz-Casado L, Villacampa A, Corzana F, Jiménez-Barbero J, Gómez AM, Santana AG, Asensio JL. Illuminating a Solvent-Dependent Hierarchy for Aromatic CH/π Complexes with Dynamic Covalent Glyco-Balances. JACS AU 2024; 4:476-490. [PMID: 38425929 PMCID: PMC10900200 DOI: 10.1021/jacsau.3c00592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 03/02/2024]
Abstract
CH/π interactions are prevalent among aromatic complexes and represent invaluable tools for stabilizing well-defined molecular architectures. Their energy contributions are exceptionally sensitive to various structural and environmental factors, resulting in a context-dependent nature that has led to conflicting findings in the scientific literature. Consequently, a universally accepted hierarchy for aromatic CH/π interactions has remained elusive. Herein, we present a comprehensive experimental investigation of aromatic CH/π complexes, employing a novel approach that involves isotopically labeled glyco-balances generated in situ. This innovative strategy not only allows us to uncover thermodynamic insights but also delves into the often less-accessible domain of kinetic information. Our analyses have yielded more than 180 new free energy values while considering key factors such as solvent properties, the interaction geometry, and the presence and nature of accompanying counterions. Remarkably, the obtained results challenge conventional wisdom regarding the stability order of common aromatic complexes. While it was believed that cationic CH/π interactions held the highest strength, followed by polarized CH/π, nonpolarized CH/π, and finally anionic CH/π interactions, our study reveals that this hierarchy can be subverted depending on the environment. Indeed, the performance of polarized CH/π interactions can match or even outcompete that of cationic CH/π interactions making them a more reliable stabilization strategy across the entire spectrum of solvent polarity. Overall, our results provide valuable guidelines for the selection of optimal interacting partners in every chemical environment, allowing the design of tailored aromatic complexes with applications in supramolecular chemistry, organocatalysis, and/or material sciences.
Collapse
Affiliation(s)
- Laura Díaz-Casado
- Departamento
de Química Bio-Orgánica, Instituto de Química
Orgánica General (IQOG-CSIC), Consejo
Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Alejandro Villacampa
- Departamento
de Química Bio-Orgánica, Instituto de Química
Orgánica General (IQOG-CSIC), Consejo
Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Francisco Corzana
- Departamento
de Química, Centro de Investigación en Síntesis
Química, Universidad de La Rioja, 26006 Logroño, Spain
| | - Jesús Jiménez-Barbero
- Basque
Researchand Technology Alliance (BRTA), CIC bioGUNE, 48170 Derio, Spain
- Basque
Foundation for Science, Ikerbasque, 48009 Bilbao, Spain
- Centro
de Investigación Biomédica En Red de Enfermedades Respiratorias, 28029 Madrid, Spain
| | - Ana M. Gómez
- Departamento
de Química Bio-Orgánica, Instituto de Química
Orgánica General (IQOG-CSIC), Consejo
Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| | - Andrés G. Santana
- Department
of Chemistry of Natural Products and Bioactive Synthetics, Instituto de Productos Naturales y Agrobiología
(IPNA-CSIC), San Cristóbal
de La Laguna, Santa Cruz de Tenerife 38206, Spain
| | - Juan Luis Asensio
- Departamento
de Química Bio-Orgánica, Instituto de Química
Orgánica General (IQOG-CSIC), Consejo
Superior de Investigaciones Científicas (CSIC), 28006 Madrid, Spain
| |
Collapse
|
2
|
Liu H, Shimizu KD. Contributions of London Dispersion Forces to Solution-Phase Association Processes. Acc Chem Res 2023; 56:3572-3580. [PMID: 38009964 DOI: 10.1021/acs.accounts.3c00539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
ConspectusDespite their ubiquity and early discovery, London dispersion forces are often overlooked. This is due, in part, to the difficulty in assessing their contributions to molecular and polymeric structure, stability, properties, and reactivities. However, recent advances in modeling have revealed that dispersion interactions play an important role in many important chemical and biological processes. Experimental confirmation of their impact in solution has been challenging, leading to controversies about their relative importance.In the course of studying noncovalent interactions using molecular devices, our understanding and appreciation for the importance of dispersion interactions have evolved. This Account follows this intellectual journey by using examples from the literature. The goals are twofold: to describe recent advances in understanding the interaction and to provide guidance to researchers studying weak noncovalent interactions. However, first, the experimental methods for measuring the effects of dispersion interactions and the strategies for isolating their influence are described. These include the design of molecular devices to measure these weak noncovalent interactions and the strategies to disentangle the solvation, solvophobic, and dispersion components of the resulting equilibria.The literature examples are organized around five fundamental questions. (1) Do dispersion interactions have a measurable effect on solution equilibria? (2) To what extent do solvents attenuate or compensate for dispersion interactions? (3) To what extent do the solvation and solvophobic terms influence the dispersion equilibria? (4) Can we predict whether a system will form attractive dispersion or repulsive steric interactions? (5) Can the dispersion term be isolated and interrogated? We were often surprised by the answers to these questions. In each case, we describe how the systems were designed to address these questions and discuss possible interpretations of the results.While dispersion interactions in solution were weak (usually <1 kcal/mol), their influence on complexation and conformational equilibria can be observed and measured. This underscores the significance of these interactions in molecular recognition, coordination chemistry, reaction design, and catalysis. The solvent components of the dispersion equilibria can also be significant. Therefore, the isolation of the dispersion contributions from the solvation and solvophobic effects represents an ongoing challenge. The experimental studies also provide important benchmarks and offer valuable insights to help refine the next generation of computational solvent models.
Collapse
Affiliation(s)
- Hao Liu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Ken D Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| |
Collapse
|
3
|
Gravillier LA, Cockroft SL. Context-Dependent Significance of London Dispersion. Acc Chem Res 2023; 56:3535-3544. [PMID: 37994023 DOI: 10.1021/acs.accounts.3c00625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
ConspectusLondon forces constitute an attractive component of van der Waals interactions and originate from transient correlated momentary dipoles in adjacent atoms. The in-depth investigation of London dispersion forces poses notable challenges, especially in solution, owing to their inherently weak and competing character. Our objective in this Account is to shed light on the context-dependent significance of London dispersion forces by contrasting our own experimental findings with those from other research endeavors. Specifically, we will explore how factors such as the choice of system and solvent can influence the apparent role of London dispersion forces in molecular recognition processes. We initiate our Account by scrutinizing the Wilcox balance, which has yielded diverse and occasionally contradictory results. Following that, we provide an overview of the role of London dispersion forces and their context-dependent variations, encompassing alkyl-alkyl, halogen-π, alkyl-π, and aromatic stacking interactions.Several experimental investigations have revealed how difficult it is to measure the significance of London dispersion in solution. Indeed, dispersion forces seldom act as the exclusive driving force in molecular recognition processes, and solvation energetics also strongly influence equilibria and kinetics. Molecular balances that bring apolar functional groups into contact have proven to be instrumental in the experimental measurement of dispersion. The intramolecular approach avoids the need to pay the entropic cost of bringing interacting groups into contact, while also enabling solvent screening. Such experimental studies have found dispersion interactions between functional groups to be very weak (<5 kJ mol-1), meaning that they frequently take backstage to electrostatic contributions and solvophobic effects and are readily damped by competitive dispersion interactions with the solvent. By using such approaches, competitive dispersion interactions with the solvent have been shown to be described by the bulk polarizability of the solvent (perfluoroalkanes have the lowest bulk polarizabilities, while carbon disulfide has one of the highest). Dispersion interactions are also strongly distance-dependent, which results in considerable context-dependent outcomes across different investigations. For example, we caution against the risk of attributing the stability of a "more sterically hindered" isomer as arising from intramolecular dispersion forces. The total energy of the system can reveal other contributions to stability, such as nonintuitive minimization of strain elsewhere in the molecule. Indeed, the delicate distance-dependent balance between sterics and London dispersion means that even subtle changes in size and geometry can lead to disparate behavior. Similarly, solvophobic effects also contribute to stabilizing contacts between bulky functional groups, which can be revealed if there is a correlation with the cohesive energy density of the solvent.
Collapse
Affiliation(s)
- Louis-Albin Gravillier
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| | - Scott L Cockroft
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster Road, Edinburgh EH9 3FJ, U.K
| |
Collapse
|
4
|
Control of Fluorescence of Organic Dyes in the Solid-State by Supramolecular Interactions. J Fluoresc 2022; 33:799-847. [PMID: 36576681 DOI: 10.1007/s10895-022-03056-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/21/2022] [Indexed: 12/29/2022]
Abstract
Fluorescent organic dyes play an essential role in the creation of new "smart" materials. Fragments and functional groups capable of free rotation around single bonds can significantly change the fluorescent organic dye's electronic structure under analyte effects, phase state transitions, or changes in temperature, pressure, and media polarity. Dependencies between steric and electronic structures become highly important in transition from a solution to a solid-state. Such transitions are accompanied by a significant increase in the dye molecular structure's rigidity due to supramolecular associates' formation such as H-bonding, π···π and dipole-dipole interactions. Among those supramolecular effects, H-bonding interactions, first of all, lead to significant molecular packing changes between loose or rigid structures, thus affecting the fluorescent dye's electronic states' energy and configuration, its fluorescent signal's position and intensity. All the functional groups and heteroatoms that are met in the organic dyes seem to be involved in the control of fluorescence via H-bonding: C-H···N, C-H···π, S = O···H-C, P = O···H, C-H···O, NH···N, C - H···C, C - H···Se, N-H···O, C - H···F, C-F···H. Effects of molecular packing of fluorescent organic dyes are successfully used in developing mechano-, piezo-, thermo- fluorochromes materials for their applications in the optical recording of information, sensors, security items, memory elements, organic light-emitting diodes (OLEDs) technologies.
Collapse
|
5
|
Sustainable Dyeing and Functionalization of Different Fibers Using Orange Peel Extract’s Antioxidants. Antioxidants (Basel) 2022; 11:antiox11102059. [DOI: 10.3390/antiox11102059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/16/2022] Open
Abstract
A diluted ethanol orange peel extract was used for sustainable dyeing and functionalization of different fabrics. The extract analysis was performed using UPLC-ESI-MS/MS; its total flavonoid (0.67 g RE/100 g d.w.) and antioxidant (2.81 g GAE/100 g d.w.) contents and antioxidant activity (IC50 of 65.5 µg/mL) were also determined. The extract dyeing performance at various dyebath pH values was evaluated using multifiber fabric. Among six fabrics, extract possessed the ability for dyeing wool, polyamide, and cellulose acetate (at pH 4.5), which color strength (K/S) values increased after washing (9.7–19.8 vs. 11.6–23.2). Extract:water ratio of 20:35 (v/v) was found to be sufficient for achieving satisfactory K/S values (i.e., 20.17, 12.56, and 10.38 for wool, polyamide, and cellulose acetate, respectively) that were slightly changed after washing. The optimal dyeing temperatures for wool, polyamide, and cellulose acetate are 55, 35, and 25 °C, while the equilibrium dye exhaustion at those temperatures was achieved after 45, 120, and 90 min, respectively. The color coordinate measurements revealed that wool and polyamide fabrics are yellower than cellulose acetate, while, compared to polyamide and cellulose acetate, wool is redder. Possible interactions between selected fabrics and extract compounds are suggested. All fabrics possessed excellent antioxidant activity (88.6–99.6%) both before and after washing. Cellulose acetate provided maximum bacterial reduction (99.99%) for Escherichia coli, and Staphylococcus aureus, which in the case of Staphylococcus aureus remained unchanged after washing. Orange peel extract could be used for simultaneous dyeing and functionalization of wool and polyamide (excellent antioxidant activity) and cellulose acetate (excellent antioxidant and antibacterial activity) fabrics.
Collapse
|
6
|
(9R,9aS,12aR,13S)-9,13-Diphenyl-9,9a,12a,13-tetrahydro-9,13-methanotriphenyleno[2,3-c]furan-10,12,14-trione. MOLBANK 2022. [DOI: 10.3390/m1435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
X-ray crystallography was used to characterise the title compound for the first time, and the 1H NMR, 13C NMR and IR spectroscopic data from earlier reports were also updated.
Collapse
|
7
|
Rösel S, Schreiner PR. Computational Chemistry as a Conceptual Game Changer: Understanding the Role of London Dispersion in Hexaphenylethane Derivatives (Gomberg Systems). Isr J Chem 2022. [DOI: 10.1002/ijch.202200002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sören Rösel
- Institute of Organic Chemistry Justus Liebig University Heinrich-Buff-Ring 17, Twitter: @prsgroupjlu 35392 Giessen Germany
| | - Peter R. Schreiner
- Institute of Organic Chemistry Justus Liebig University Heinrich-Buff-Ring 17, Twitter: @prsgroupjlu 35392 Giessen Germany
| |
Collapse
|
8
|
Wang C, Shen S, Li Y, Pan H, Zhou Z, Li J, Wu B, Jing S, Guo C, Fan J, Guo H. The influence of the size of aromatic monomers on the structure and catalytic activity of polymer solid acids. NEW J CHEM 2022. [DOI: 10.1039/d1nj02596a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High activity hyper-crosslinked polymer solid acids (HCPSAs) were prepared from different aromatic monomers, and the structure was regulated by selecting the type and size of aromatic monomers.
Collapse
Affiliation(s)
- Cui Wang
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Shuguang Shen
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Yehui Li
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Huajie Pan
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Zijian Zhou
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Jing Li
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Bin Wu
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Shuaiqi Jing
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Chenyuan Guo
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Jimin Fan
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| | - Hongsheng Guo
- College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China
| |
Collapse
|
9
|
Pramanik S, Pathak S, Frontera A, Mukhopadhyay S. Syntheses, crystal structures and supramolecular assemblies of two Cu( ii) complexes based on a new heterocyclic ligand: insights into C–H⋯Cl and π⋯π interactions. CrystEngComm 2022. [DOI: 10.1039/d1ce01402a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A new heterocyclic ligand, N3L [4-(1-methylimidazole)-2,6-di(pyrazinyl)pyridine] and two Cu(ii) complexes have been synthesized and characterized by several spectroscopic and DFT methods.
Collapse
Affiliation(s)
- Samit Pramanik
- Department of Chemistry, Jadavpur University, Kolkata 700032, India
| | - Sudipta Pathak
- Department of Chemistry, Haldia Government College, Purba Medinipur, 721657, Debhog, West Bengal, India
| | - Antonio Frontera
- Departament de Química, Universitat de les Illes Balears, Crta. de Valldemossa km 7.5, 07122 Palma de Mallorca, Baleares, Spain
| | | |
Collapse
|
10
|
Abstract
Carbohydrate recognition is crucial for biological processes ranging from development to immune system function to host-pathogen interactions. The proteins that bind glycans are faced with a daunting task: to coax these hydrophilic species out of water and into a binding site. Here, we examine the forces underlying glycan recognition by proteins. Our previous bioinformatic study of glycan-binding sites indicated that the most overrepresented side chains are electron-rich aromatic residues, including tyrosine and tryptophan. These findings point to the importance of CH-π interactions for glycan binding. Studies of CH-π interactions show a strong dependence on the presence of an electron-rich π system, and the data indicate binding is enhanced by complementary electronic interactions between the electron-rich aromatic ring and the partial positive charge of the carbohydrate C-H protons. This electronic dependence means that carbohydrate residues with multiple aligned highly polarized C-H bonds, such as β-galactose, form strong CH-π interactions, whereas less polarized residues such as α-mannose do not. This information can guide the design of proteins to recognize sugars and the generation of ligands for proteins, small molecules, or catalysts that bind sugars.
Collapse
Affiliation(s)
- Laura L. Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Roger C. Diehl
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
11
|
Ahirwar MB, Gurav ND, Gadre SR, Deshmukh MM. Molecular Tailoring Approach for Estimating Individual Intermolecular Interaction Energies in Benzene Clusters. J Phys Chem A 2021; 125:6131-6140. [PMID: 34251827 DOI: 10.1021/acs.jpca.1c03907] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There is no general method available for the estimation of individual intermolecular interaction energies in weakly bound molecular clusters, and such studies are limited only to the dimer. Recently, we proposed a molecular tailoring approach-based method for the estimation of individual O-H···O hydrogen bond energies in water clusters. In the present work, we extend the applicability of this method for estimating the individual intermolecular interaction energies in benzene clusters, which are expected to be small. The basis set superposition error (BSSE)-corrected individual intermolecular interaction energies in linear (LN) benzene clusters, LN-(Bz)n n = 3-7, were calculated to be in the range from -1.75 to -2.33 kcal/mol with the cooperativity contribution falling between 0.05 and 0.20 kcal/mol, calculated at the MP2.5/aug-cc-pVDZ level of theory. In the case of non-linear (NLN) benzene clusters, NLN-(Bz)n n = 3-5, the BSSE-corrected individual intermolecular interaction energies exhibit a wider range from -1.16 to -2.55 kcal/mol with cooperativity contribution in the range from 0.02 to -0.61 kcal/mol. The accuracy of these estimated values was validated by adding the sum of interaction energies to the sum of monomer energies. These estimated molecular energies of clusters were compared with their actual calculated values. The small difference (<0.3 kcal/mol) in these two values suggests that our estimated individual intermolecular interaction energies in benzene clusters are quite reliable.
Collapse
Affiliation(s)
- Mini Bharati Ahirwar
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar 470003, India
| | - Nalini D Gurav
- Department of Scientific Computing, Modelling and Simulation, Savitribai Phule Pune University, Pune 411 007, India
| | - Shridhar R Gadre
- Department of Scientific Computing, Modelling and Simulation, Savitribai Phule Pune University, Pune 411 007, India
| | - Milind M Deshmukh
- Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya (A Central University), Sagar 470003, India
| |
Collapse
|
12
|
Ghosh P, Chatterjee J. CH-π interaction between cross-strand amino acid pairs stabilizes β-hairpins. Chem Commun (Camb) 2020; 56:14447-14450. [PMID: 33146171 DOI: 10.1039/d0cc05653g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We identified several CH-π donor-acceptor pairs involving amino acid side chains with less polarized C-H bonds at a solvent-exposed site between the strands of a β-hairpin peptide. Therein, we observe a distance-dependent induction of CH-π interaction within the aliphatic-aromatic amino acid pair. Our results also suggest an interplay of hydrophobicity and CH-π interaction in dictating the stability of β-hairpins, where a leucine-tryptophan pair contributes -1.14 kcal mol-1 to the overall foldedness of the β-hairpin.
Collapse
Affiliation(s)
- Pritha Ghosh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
| | | |
Collapse
|
13
|
Li P, Vik EC, Shimizu KD. N-Arylimide Molecular Balances: A Comprehensive Platform for Studying Aromatic Interactions in Solution. Acc Chem Res 2020; 53:2705-2714. [PMID: 33152232 DOI: 10.1021/acs.accounts.0c00519] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Noncovalent interactions of aromatic surfaces play a key role in many biological processes and in determining the properties and utility of synthetic materials, sensors, and catalysts. However, the study of aromatic interactions has been challenging because these interactions are usually very weak and their trends are modulated by many factors such as structural, electronic, steric, and solvent effects. Recently, N-arylimide molecular balances have emerged as highly versatile and effective platforms for studying aromatic interactions in solution. These molecular balances can accurately measure weak noncovalent interactions in solution via their influence on the folded-unfolded conformational equilibrium. The structure (i.e., size, shape, π-conjugation, and substitution) and nature (i.e., element, charge, and polarity) of the π-surfaces and interacting groups can be readily varied, enabling the study of a wide range of aromatic interactions. These include aromatic stacking, heterocyclic aromatic stacking, and alkyl-π, chalcogen-π, silver-π, halogen-π, substituent-π, and solvent-π interactions. The ability to measure a diverse array of aromatic interactions within a single model system provides a unique perspective and insights as the interaction energies, stability trends, and solvent effects for different types of interactions can be directly compared. Some broad conclusions that have emerged from this comprehensive analysis include: (1) The strongest aromatic interactions involve groups with positive charges such as pyridinium and metal ions which interact with the electrostatically negative π-face of the aromatic surface via cation-π or metal-π interactions. Attractive electrostatic interactions can also form between aromatic surfaces and groups with partial positive charges. (2) Electrostatic interactions involving aromatic surfaces can be switched from repulsive to attractive using electron-withdrawing substituents or heterocycles. These electrostatic trends appear to span many types of aromatic interactions involving a polar group interacting with a π-surface such as halogen-π, chalcogen-π, and carbonyl-π. (3) Nonpolar groups form weak but measurable stabilizing interactions with aromatic surfaces in organic solvents due to favorable dispersion and/or solvophobic effects. A good predictor of the interaction strength is provided by the change in solvent-accessible surface area. (4) Solvent effects modulate the aromatic interactions in the forms of solvophobic effects and competitive solvation, which can be modeled using solvent cohesion density and specific solvent-solute interactions.
Collapse
Affiliation(s)
- Ping Li
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Erik C. Vik
- Vertex Pharmaceuticals, 50 Northern Avenue, Boston, Massachusetts 02210, United States
| | - Ken D. Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| |
Collapse
|
14
|
Tanaka D, Tsutsui Y, Konishi A, Nakaoka K, Nakajima H, Baba A, Chiba K, Yasuda M. Selective Activation of Aromatic Aldehydes Promoted by Dispersion Interactions: Steric and Electronic Factors of a π-Pocket within Cage-Shaped Borates for Molecular Recognition. Chemistry 2020; 26:15023-15034. [PMID: 32870540 DOI: 10.1002/chem.202003594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Indexed: 12/13/2022]
Abstract
Selective bond formations are one of the most important reactions in organic synthesis. In the Lewis acid mediated electrophile reactions of carbonyls, the selective formation of a carbonyl-acid complex plays a critical role in determining selectivity, which is based on the difference in the coordinative interaction between the carbonyl and Lewis acid center. Although this strategy has attained progress in selective bond formations, the discrimination between similarly sized aromatic and aliphatic carbonyls that have no functional anchors to strongly interact with the metal center still remains a challenging issue. Herein, this work focuses on molecular recognition driven by dispersion interactions within some aromatic moieties. A Lewis acid catalyst with a π-space cavity, which is referred to as a π-pocket, as the recognition site for aromatic carbonyls is designed. Cage-shaped borates 1B with various π-pockets demonstrated significant chemoselectivity for aromatic aldehydes 3 b-f over that of aliphatic 3 a in competitive hetero-Diels-Alder reactions. The effectiveness of our catalysts was also evidenced by intramolecular recognition of the aromatic carbonyl within a dicarbonyl substrate. Mechanistic and theoretical studies demonstrated that the selective activation of aromatic substrates was driven by the preorganization step with a larger dispersion interaction, rather than the rate-determining step of the C-C bond formation, and this was likely to contribute to the preferred activation of aromatic substrates over that of aliphatic ones.
Collapse
Affiliation(s)
- Daiki Tanaka
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Yuya Tsutsui
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Akihito Konishi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan.,Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Koichi Nakaoka
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Hideto Nakajima
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Akio Baba
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| | - Kouji Chiba
- Material Science Division, MOLSIS Inc., 1-28-38 Shinkawa, Chuo-ku, Tokyo, 1040033, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 5650871, Japan
| |
Collapse
|
15
|
Kobayashi H, Okada K, Tokuda S, Kanao E, Masuda Y, Naito T, Takaya H, Yan M, Kubo T, Otsuka K. Separation of saccharides using fullerene-bonded silica monolithic columns via π interactions in liquid chromatography. Sci Rep 2020; 10:13850. [PMID: 32796903 PMCID: PMC7429847 DOI: 10.1038/s41598-020-70904-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/04/2020] [Indexed: 02/06/2023] Open
Abstract
We report on a potential method to separate sugars by using the specific interaction between fullerenes and saccharides in liquid chromatography (LC). Aromatic rings with high electron density are believed to interact strongly with saccharides due to CH–π and/or OH–π interactions. In this study, the fullerene-bonded columns were used to separate saccharides by LC under aqueous conditions. As a result, 2-aminobenzamide-labeled glucose homopolymer (Glcs) was effectively separated by both C60 and C70 columns in the range of Glc-1 to Glc-20 and high blood glucose level being retained in greater quantity. Furthermore, similar separations were identified by LC–mass spectrometry with non-labeled glucose homopolymers. Theoretical study based on molecular dynamics and DFT calculation demonstrated that a supramolecular complex of saccharide–fullerene was formed through CH–π and/or OH–π interactions, and that the interactions between saccharide and fullerene increase with the increase units of the saccharide. Additionally, the C60 column retained disaccharides containing maltose, trehalose, and sucrose. In this case, it was assumed that the retention rates were determined by the difference of the dipole moment in each saccharide. These results suggest that the dipole-induced dipole interaction was dominant, and that maltose—with the higher dipole moment—was more strongly retained compared to other disaccharides having lower dipole moment.
Collapse
Affiliation(s)
- Hiroshi Kobayashi
- Shinwa Chemical Industries Ltd., 50-2, Kagekatsu-cho, Fushimi-ku, Kyoto, 612-8307, Japan
| | - Kazuya Okada
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| | - Shinnosuke Tokuda
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| | - Eisuke Kanao
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| | - Yusuke Masuda
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| | - Toyohiro Naito
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| | - Hikaru Takaya
- Institute of Chemical Research, Kyoto University, Gokashou, Uji, Kyoto, 611-0011, Japan
| | - Mingdi Yan
- Department of Chemistry, University of Massachusetts Lowell, One University Ave., Lowell, MA, 01854, USA
| | - Takuya Kubo
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan.
| | - Koji Otsuka
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Katsura, Kyoto, 615-8510, Japan
| |
Collapse
|
16
|
Vik EC, Li P, Maier JM, Madukwe DO, Rassolov VA, Pellechia PJ, Masson E, Shimizu KD. Large transition state stabilization from a weak hydrogen bond. Chem Sci 2020; 11:7487-7494. [PMID: 34123031 PMCID: PMC8159443 DOI: 10.1039/d0sc02806a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A series of molecular rotors was designed to study and measure the rate accelerating effects of an intramolecular hydrogen bond. The rotors form a weak neutral O–H⋯O
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
C hydrogen bond in the planar transition state (TS) of the bond rotation process. The rotational barrier of the hydrogen bonding rotors was dramatically lower (9.9 kcal mol−1) than control rotors which could not form hydrogen bonds. The magnitude of the stabilization was significantly larger than predicted based on the independently measured strength of a similar O–H⋯OC hydrogen bond (1.5 kcal mol−1). The origins of the large transition state stabilization were studied via experimental substituent effect and computational perturbation analyses. Energy decomposition analysis of the hydrogen bonding interaction revealed a significant reduction in the repulsive component of the hydrogen bonding interaction. The rigid framework of the molecular rotors positions and preorganizes the interacting groups in the transition state. This study demonstrates that with proper design a single hydrogen bond can lead to a TS stabilization that is greater than the intrinsic interaction energy, which has applications in catalyst design and in the study of enzyme mechanisms. A series of molecular rotors was designed to study and measure the rate accelerating effects of an intramolecular hydrogen bond.![]()
Collapse
Affiliation(s)
- Erik C Vik
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Ping Li
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Josef M Maier
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Daniel O Madukwe
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Vitaly A Rassolov
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Perry J Pellechia
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| | - Eric Masson
- Department of Chemistry and Biochemistry, Ohio University Athens OH 45701 USA
| | - Ken D Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina Columbia SC 29208 USA
| |
Collapse
|
17
|
Salami F, Zhao Y. Synthesis and characterization of bis(dithiafulvenyl)-substituted fluorenones and fluorenylidene-1,3-dithioles. NEW J CHEM 2020. [DOI: 10.1039/d0nj01495h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A series of π-conjugated oligomers containing redox-active dithiafulvenyl (DTF) end groups and fluorenone/fluorenylidene-1,3-dithiole central units was synthesized and their structural, electronic, and electrochemical properties were investigated.
Collapse
Affiliation(s)
- Fatemeh Salami
- Department of Chemistry
- Memorial University of Newfoundland
- St. John's
- Canada
| | - Yuming Zhao
- Department of Chemistry
- Memorial University of Newfoundland
- St. John's
- Canada
| |
Collapse
|
18
|
Wang J, Yao L. Dissecting C-H∙∙∙π and N-H∙∙∙π Interactions in Two Proteins Using a Combined Experimental and Computational Approach. Sci Rep 2019; 9:20149. [PMID: 31882834 PMCID: PMC6934659 DOI: 10.1038/s41598-019-56607-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 12/12/2019] [Indexed: 01/27/2023] Open
Abstract
C−H∙∙∙π and N−H∙∙∙π interactions can have an important contribution for protein stability. However, direct measurements of these interactions in proteins are rarely reported. In this work, we combined the mutant cycle experiments and molecular dynamics (MD) simulations to characterize C−H∙∙∙π and N−H∙∙∙π interactions and their cooperativity in two model proteins. It is shown that the average C−H∙∙∙π interaction per residue pair is ~ −0.5 kcal/mol while the N−H∙∙∙π interaction is slightly stronger. The triple mutant box measurement indicates that N−H∙∙∙π∙∙∙C−H∙∙∙π and C−H∙∙∙π∙∙∙C−H∙∙∙π can have a positive or negative cooperativity. MD simulations suggest that the cooperativity, depending on the local environment of the interactions, mainly arises from the geometric rearrangement when the nearby interaction is perturbed.
Collapse
Affiliation(s)
- Jia Wang
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lishan Yao
- Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China. .,Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
| |
Collapse
|
19
|
Yang H, Liu YL, Tao YY, Yang W, Yang CP, Zhang J, Qian LZ, Liu H, Wang ZY. Bioinformatic and biochemical analysis of the key binding sites of the pheromone binding protein of Cyrtotrachelus buqueti Guerin-Meneville (Coleoptera: Curculionidea). PeerJ 2019; 7:e7818. [PMID: 31632851 PMCID: PMC6796961 DOI: 10.7717/peerj.7818] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 09/03/2019] [Indexed: 12/19/2022] Open
Abstract
The bamboo snout beetle Cyrtotrachelus buqueti is a widely distributed wood-boring pest found in China, and its larvae cause significant economic losses because this beetle targets a wide range of host plants. A potential pest management measure of this beetle involves regulating olfactory chemoreceptors. In the process of olfactory recognition, pheromone-binding proteins (PBPs) play an important role. Homology modeling and molecular docking were conducted in this study for the interaction between CbuqPBP1 and dibutyl phthalate to better understand the relationship between PBP structures and their ligands. Site-directed mutagenesis and binding experiments were combined to identify the binding sites of CbuqPBP1 and to explore its ligand-binding mechanism. The 3D structural model of CbuqPBP1 has six a-helices. Five of these a-helices adopt an antiparallel arrangement to form an internal ligand-binding pocket. When docking dibutyl phthalate within the active site of CbuqPBP1, a CH-π interaction between the benzene ring of dibutyl phthalate and Phe69 was observed, and a weak hydrogen bond formed between the ester carbonyl oxygen and His53. Thus, Phe69 and His53 are predicted to be important residues of CbuqPBP1 involved in ligand recognition. Site-directed mutagenesis and fluorescence assays with a His53Ala CbuqPBP1 mutant showed no affinity toward ligands. Mutation of Phe69 only affected binding of CbuqPBP1 to cedar camphor. Thus, His53 (Between α2 and α3) of CbuqPBP1 appears to be a key binding site residue, and Phe69 (Located at α3) is a very important binding site for particular ligand interactions.
Collapse
Affiliation(s)
- Hua Yang
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Yan-Lin Liu
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Yuan-Yuan Tao
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Wei Yang
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Chun-Ping Yang
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Jing Zhang
- Provincial Key Laboratory of Agricultural Environmental Engineering, Sichuan Agricultural University, Chengdu, China
| | - Li-Zhi Qian
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Hao Liu
- Sichuan Agricultural University, Key Laboratory of Ecological Forestry Engineering of Sichuan Province/ College of Forestry, Chengdu, Sichuan, China
| | - Zhi-Yong Wang
- Key Laboratory of Control and Resource Development of Bamboo Pest of Sichuan Province, Leshan, China
| |
Collapse
|
20
|
Li P, Vik EC, Maier JM, Karki I, Strickland SMS, Umana JM, Smith MD, Pellechia PJ, Shimizu KD. Electrostatically Driven CO−π Aromatic Interactions. J Am Chem Soc 2019; 141:12513-12517. [DOI: 10.1021/jacs.9b06363] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ping Li
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Erik C. Vik
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Josef M. Maier
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Ishwor Karki
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Sharon M. S. Strickland
- Department of Biology, Chemistry, and Physics, Converse College, Spartanburg, South Carolina 29302, United States
| | - Jessica M. Umana
- Department of Biology, Chemistry, and Physics, Converse College, Spartanburg, South Carolina 29302, United States
| | - Mark D. Smith
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Perry J. Pellechia
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Ken D. Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| |
Collapse
|
21
|
Hwang J, Li P, Vik EC, Karki I, Shimizu KD. Study of through-space substituent–π interactions using N-phenylimide molecular balances. Org Chem Front 2019. [DOI: 10.1039/c9qo00195f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Substituent–π interactions associated with aromatic stacking interactions were experimentally measured using a small N-phenylimide molecular balance model system.
Collapse
Affiliation(s)
- Jungwun Hwang
- Department of Chemistry and Biochemistry
- University of South Carolina
- Columbia
- USA
| | - Ping Li
- Department of Chemistry and Biochemistry
- University of South Carolina
- Columbia
- USA
| | - Erik C. Vik
- Department of Chemistry and Biochemistry
- University of South Carolina
- Columbia
- USA
| | - Ishwor Karki
- Department of Chemistry and Biochemistry
- University of South Carolina
- Columbia
- USA
| | - Ken D. Shimizu
- Department of Chemistry and Biochemistry
- University of South Carolina
- Columbia
- USA
| |
Collapse
|
22
|
Samie A, Salimi A, Garrison JC. Exploration of relative π-electron localization in naphthalene aromatic rings by C–H⋯π interactions: experimental evidence, computational criteria, and database analysis. CrystEngComm 2019. [DOI: 10.1039/c9ce00929a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In C–H⋯π interaction, the relative π-electron localization in aromatic ring led to the change of contact position from centre to edges of the ring (C–H⋯πe) which was confirmed by experimental evidences, computational criteria, and database analysis.
Collapse
Affiliation(s)
- Ali Samie
- Department of Chemistry
- Faculty of Science
- Ferdowsi University of Mashhad
- Mashhad
- Iran
| | - Alireza Salimi
- Department of Chemistry
- Faculty of Science
- Ferdowsi University of Mashhad
- Mashhad
- Iran
| | - Jered C. Garrison
- Department of Pharmaceutical Sciences
- University of Nebraska Medical Centre
- USA
| |
Collapse
|
23
|
Hwang J, Li P, Smith MD, Warden CE, Sirianni DA, Vik EC, Maier JM, Yehl CJ, Sherrill CD, Shimizu KD. Tipping the Balance between S-π and O-π Interactions. J Am Chem Soc 2018; 140:13301-13307. [PMID: 30251855 DOI: 10.1021/jacs.8b07617] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A comprehensive experimental survey consisting of 36 molecular balances was conducted to compare 18 pairs of S-π versus O-π interactions over a wide range of structural, geometric, and solvent parameters. A strong linear correlation was observed between the folding energies of the sulfur and oxygen balances across the entire library of balance pairs. The more stable interaction systematically switched from the O-π to S-π interaction. Computational studies of bimolecular PhSCH3-arene and PhOCH3-arene complexes were able to replicate the experimental trends in the molecular balances. The change in preference for the O-π to S-π interaction was due to the interplay of stabilizing (dispersion and solvophobic) and destabilizing (exchange-repulsion) terms arising from the differences in size and polarizability of the oxygen and sulfur atoms.
Collapse
Affiliation(s)
- Jungwun Hwang
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Ping Li
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Mark D Smith
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | | | | | - Erik C Vik
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Josef M Maier
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Christopher J Yehl
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | | | - Ken D Shimizu
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| |
Collapse
|
24
|
Shen C, Gong Z, Gao L, Gu M, Huan L, Wang S, Xie J. Theoretical study on host-guest interaction between pillar[4]arene and molecules or ions. J Mol Model 2018; 24:199. [PMID: 29987452 DOI: 10.1007/s00894-018-3736-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
Abstract
In order to systematically explore the general rule of the host-guest chemistry for pillararenes, this work investigates the weak interactions between pillar[4]arene and some typical guests (anions, cations, and dumbbell-shaped molecules) by using density functional theory (DFT) calculations at the ωB97XD/6-311G(d,p) level. The strong molecular recognition ability of pillar[4]arene has been discussed based on the geometry structure, electronic structure, and thermodynamic properties of the host-guest complexes. The results show that the equivalent lower and upper rims of the pillar[4]arene can be combined with both anion and cation, and its cavity can accommodate the alkyl part of the dumbbell-shaped molecule. The main host-guest interactions between pillar[4]arene and guests are hydrogen bond, cation-π, anion-π, and hydrophobic interaction by visualization of weak interactions using the Multiwfn program. Pillar[4]arene will form a more stable host-guest complex with the guest, which possesses conjugate structure and weak steric repulsion. This work intends to provide a theoretical basis for enriching the host-guest chemistry, understanding the supramolecular morphology, and expanding the applications of the pillararenes.
Collapse
Affiliation(s)
- Chao Shen
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China
| | - Zhenyu Gong
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China
| | - Lei Gao
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China
| | - Minglong Gu
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China
| | - Long Huan
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China
| | - Sicong Wang
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin, 300071, China
| | - Ju Xie
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, 225002, Jiangsu, China.
- Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin, 300071, China.
| |
Collapse
|
25
|
Sharafi M, Campbell JP, Rajappan SC, Dudkina N, Gray DL, Woods TJ, Li J, Schneebeli ST. Crystal-Packing-Driven Enrichment of Atropoisomers. Angew Chem Int Ed Engl 2017; 56:7097-7101. [PMID: 28510353 DOI: 10.1002/anie.201701876] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 04/17/2017] [Indexed: 11/10/2022]
Abstract
Crystal-packing forces can have a significant impact on the relative stabilities of different molecules and their conformations. The magnitude of such effects is, however, not yet well understood. Herein we show, that crystal packing can completely overrule the relative stabilities of different stereoisomers in solution. Heating of atropoisomers (i.e. "frozen-out" conformational isomers) in solution leads to complex mixtures. In contrast, solid-state heating selectively amplifies minor (<25 mole %) components of these solution-phase mixtures. We show that this heating strategy is successful for compounds with up to four rotationally hindered σ bonds, for which a single stereoisomer out of seven can be amplified selectively. Our results demonstrate that common supramolecular interactions-for example, [methyl⋅⋅⋅π] coordination and [C-H⋅⋅⋅O] hydrogen bonding-can readily invert the relative thermodynamic stabilities of different molecular conformations. These findings open up potential new avenues to control the folding of macromolecules.
Collapse
Affiliation(s)
- Mona Sharafi
- Department of Chemistry, The University of Vermont, Burlington, VT, 05405, USA
| | - Joseph P Campbell
- Department of Chemistry, The University of Vermont, Burlington, VT, 05405, USA
| | - Sinu C Rajappan
- Department of Chemistry, The University of Vermont, Burlington, VT, 05405, USA
| | - Natavan Dudkina
- Department of Chemistry, The University of Vermont, Burlington, VT, 05405, USA
| | - Danielle L Gray
- George L. Clark X-Ray Facility & 3M Materials Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Toby J Woods
- George L. Clark X-Ray Facility & 3M Materials Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jianing Li
- Department of Chemistry, The University of Vermont, Burlington, VT, 05405, USA
| | | |
Collapse
|
26
|
Sharafi M, Campbell JP, Rajappan SC, Dudkina N, Gray DL, Woods TJ, Li J, Schneebeli ST. Crystal‐Packing‐Driven Enrichment of Atropoisomers. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701876] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Mona Sharafi
- Department of Chemistry The University of Vermont Burlington VT 05405 USA
| | - Joseph P. Campbell
- Department of Chemistry The University of Vermont Burlington VT 05405 USA
| | - Sinu C. Rajappan
- Department of Chemistry The University of Vermont Burlington VT 05405 USA
| | - Natavan Dudkina
- Department of Chemistry The University of Vermont Burlington VT 05405 USA
| | - Danielle L. Gray
- George L. Clark X-Ray Facility & 3M Materials Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Toby J. Woods
- George L. Clark X-Ray Facility & 3M Materials Laboratory University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Jianing Li
- Department of Chemistry The University of Vermont Burlington VT 05405 USA
| | | |
Collapse
|
27
|
Maier JM, Li P, Vik EC, Yehl CJ, Strickland SMS, Shimizu KD. Measurement of Solvent OH−π Interactions Using a Molecular Balance. J Am Chem Soc 2017; 139:6550-6553. [DOI: 10.1021/jacs.7b02349] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Josef M. Maier
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Ping Li
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Erik C. Vik
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Christopher J. Yehl
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Sharon M. S. Strickland
- Department
of Biology, Chemistry, and Physics, Converse College, Spartanburg, South Carolina 29302, United States
| | - Ken D. Shimizu
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| |
Collapse
|
28
|
Li P, Maier JM, Vik EC, Yehl CJ, Dial BE, Rickher AE, Smith MD, Pellechia PJ, Shimizu KD. Stabilizing Fluorine–π Interactions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201702950] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Ping Li
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Josef M. Maier
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Erik C. Vik
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Christopher J. Yehl
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Brent E. Dial
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Amanda E. Rickher
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Mark D. Smith
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Perry J. Pellechia
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Ken D. Shimizu
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| |
Collapse
|
29
|
Li P, Maier JM, Vik EC, Yehl CJ, Dial BE, Rickher AE, Smith MD, Pellechia PJ, Shimizu KD. Stabilizing Fluorine–π Interactions. Angew Chem Int Ed Engl 2017; 56:7209-7212. [DOI: 10.1002/anie.201702950] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Ping Li
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Josef M. Maier
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Erik C. Vik
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Christopher J. Yehl
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Brent E. Dial
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Amanda E. Rickher
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Mark D. Smith
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Perry J. Pellechia
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| | - Ken D. Shimizu
- Department of Chemistry and Biochemistry University of South Carolina Columbia SC 29208 USA
| |
Collapse
|
30
|
Yamada S, Yamamoto N, Takamori E. Synthesis of Molecular Seesaw Balances and the Evaluation of Pyridinium−π Interactions. J Org Chem 2016; 81:11819-11830. [DOI: 10.1021/acs.joc.6b02295] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shinji Yamada
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku,
Tokyo 112-8610, Japan
| | - Natsuo Yamamoto
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku,
Tokyo 112-8610, Japan
| | - Eri Takamori
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku,
Tokyo 112-8610, Japan
| |
Collapse
|
31
|
Chung MK, White PS, Lee SJ, Gagné MR, Waters ML. Investigation of a Catenane with a Responsive Noncovalent Network: Mimicking Long-Range Responses in Proteins. J Am Chem Soc 2016; 138:13344-13352. [PMID: 27631725 PMCID: PMC5553285 DOI: 10.1021/jacs.6b07833] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report a functional synthetic model for studying the noncovalent networks (NCNs) required for complex protein functions. The model [2]-catenane is self-assembled from dipeptide building blocks and contains an extensive network of hydrogen bonds and aromatic interactions. Perturbations to the catenane cause compensating changes in the NCNs structure and dynamics, resulting in long-distance changes reminiscent of a protein. Key findings include the notion that NCNs require regions of negative cooperativity, or "frustrated" noncovalent interactions, as a source of potential energy for driving the response. We refer to this potential energy as latent free energy and describe a mechanistic and energetic model for responsive systems.
Collapse
Affiliation(s)
| | | | - Stephen J. Lee
- U.S. Army Research Office, P.O. Box 12211, Research Triangle Park, North Carolina 27709, United States
| | | | | |
Collapse
|
32
|
Yamate T, Kumazawa K, Suzuki H, Akazome M. CH/π Interactions for Macroscopic Interfacial Adhesion Design. ACS Macro Lett 2016; 5:858-861. [PMID: 35614771 DOI: 10.1021/acsmacrolett.6b00265] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Adhesion to chemically inert materials without surface modification through noncovalent interactions represents a challenging task in adhesion science. We successfully develop for the first time a strategy utilizing multiple CH/π interactions that use poly(methacrylate) with an aromatic group (H acceptor) in the ester part and polyolefin materials (H donor). The strength increases with the number of π electrons and aromatic rings. The trityl methacrylate polymer emerges as the most effective H-acceptor polymer for obtaining strong adhesion to various polyolefin materials. This work will provide not only a promising adhesion strategy that does not require surface activation for polyolefin materials, but also a novel approach using weak noncovalent interactions.
Collapse
Affiliation(s)
- Taiki Yamate
- Nippon Soda Co.
Ltd., Chiba Research Center, 12-54
Goi-minamikaigan, Ichihara, Chiba 290-0045, Japan
- Department
of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoicho, Inageku, Chiba, 263-8522, Japan
| | - Kazuhisa Kumazawa
- Nippon Soda Co.
Ltd., Chiba Research Center, 12-54
Goi-minamikaigan, Ichihara, Chiba 290-0045, Japan
| | - Hiroshi Suzuki
- Nippon Soda Co.
Ltd., Chiba Research Center, 12-54
Goi-minamikaigan, Ichihara, Chiba 290-0045, Japan
| | - Motohiro Akazome
- Department
of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoicho, Inageku, Chiba, 263-8522, Japan
| |
Collapse
|
33
|
Abstract
On the basis of many literature measurements, a critical overview is given on essential noncovalent interactions in synthetic supramolecular complexes, accompanied by analyses with selected proteins. The methods, which can be applied to derive binding increments for single noncovalent interactions, start with the evaluation of consistency and additivity with a sufficiently large number of different host-guest complexes by applying linear free energy relations. Other strategies involve the use of double mutant cycles, of molecular balances, of dynamic combinatorial libraries, and of crystal structures. Promises and limitations of these strategies are discussed. Most of the analyses stem from solution studies, but a few also from gas phase. The empirically derived interactions are then presented on the basis of selected complexes with respect to ion pairing, hydrogen bonding, electrostatic contributions, halogen bonding, π-π-stacking, dispersive forces, cation-π and anion-π interactions, and contributions from the hydrophobic effect. Cooperativity in host-guest complexes as well as in self-assembly, and entropy factors are briefly highlighted. Tables with typical values for single noncovalent free energies and polarity parameters are in the Supporting Information.
Collapse
Affiliation(s)
- Frank Biedermann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Hans-Jörg Schneider
- FR Organische Chemie der Universität des Saarlandes , D-66041 Saarbrücken, Germany
| |
Collapse
|
34
|
Yang L, Brazier JB, Hubbard TA, Rogers DM, Cockroft SL. Can Dispersion Forces Govern Aromatic Stacking in an Organic Solvent? Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201508056] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lixu Yang
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - John B. Brazier
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - Thomas A. Hubbard
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - David M. Rogers
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - Scott L. Cockroft
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| |
Collapse
|
35
|
Yang L, Brazier JB, Hubbard TA, Rogers DM, Cockroft SL. Can Dispersion Forces Govern Aromatic Stacking in an Organic Solvent? Angew Chem Int Ed Engl 2015; 55:912-6. [DOI: 10.1002/anie.201508056] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/13/2015] [Indexed: 12/27/2022]
Affiliation(s)
- Lixu Yang
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - John B. Brazier
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - Thomas A. Hubbard
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - David M. Rogers
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| | - Scott L. Cockroft
- EaStCHEM School of Chemistry; University of Edinburgh, Joseph Black Building; David Brewster Road Edinburgh EH9 3FJ UK
| |
Collapse
|
36
|
Yamada S, Yamamoto N, Takamori E. A Molecular Seesaw Balance: Evaluation of Solvent and Counteranion Effects on Pyridinium−π Interactions. Org Lett 2015; 17:4862-5. [DOI: 10.1021/acs.orglett.5b02420] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Shinji Yamada
- Department of Chemistry,
Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo112-8610, Japan
| | - Natsuo Yamamoto
- Department of Chemistry,
Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo112-8610, Japan
| | - Eri Takamori
- Department of Chemistry,
Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo112-8610, Japan
| |
Collapse
|
37
|
Ams MR, Fields M, Grabnic T, Janesko BG, Zeller M, Sheridan R, Shay A. Unraveling the Role of Alkyl F on CH−π Interactions and Uncovering the Tipping Point for Fluorophobicity. J Org Chem 2015; 80:7764-9. [DOI: 10.1021/acs.joc.5b01072] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Mark R. Ams
- Department
of Chemistry, Allegheny College, 520 North Main Street, Meadville, Pennsylvania 16335-3902, United States
| | - Michael Fields
- Department
of Chemistry, Allegheny College, 520 North Main Street, Meadville, Pennsylvania 16335-3902, United States
| | - Timothy Grabnic
- Department
of Chemistry, Allegheny College, 520 North Main Street, Meadville, Pennsylvania 16335-3902, United States
| | - Benjamin G. Janesko
- Department
of Chemistry, Texas Christian University, 2800 Souh University Drive, Fort Worth, Texas 76109, United States
| | - Matthias Zeller
- Department
of Chemistry, Youngstown State University, One University Plaza, Youngstown, Ohio 44555, United States
| | - Rose Sheridan
- Department
of Chemistry, Allegheny College, 520 North Main Street, Meadville, Pennsylvania 16335-3902, United States
| | - Amanda Shay
- Department
of Chemistry, Allegheny College, 520 North Main Street, Meadville, Pennsylvania 16335-3902, United States
| |
Collapse
|
38
|
Harder M, Carnero Corrales MA, Trapp N, Kuhn B, Diederich F. Rebek Imide Platforms as Model Systems for the Investigation of Weak Intermolecular Interactions. Chemistry 2015; 21:8455-63. [DOI: 10.1002/chem.201500462] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Indexed: 11/09/2022]
|
39
|
Li P, Parker TM, Hwang J, Deng F, Smith MD, Pellechia PJ, Sherrill CD, Shimizu KD. The CH−π Interactions of Methyl Ethers as a Model for Carbohydrate–N-Heteroarene Interactions. Org Lett 2014; 16:5064-7. [DOI: 10.1021/ol502418k] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ping Li
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Trent M. Parker
- Center
for Computational Molecular Science and Technology, School of Chemistry
and Biochemistry and School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jungwun Hwang
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Fengyuan Deng
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Mark D. Smith
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Perry J. Pellechia
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - C. David Sherrill
- Center
for Computational Molecular Science and Technology, School of Chemistry
and Biochemistry and School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ken D. Shimizu
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| |
Collapse
|