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Ramamurthy V. Photochemistry in a capsule: controlling excited state dynamics via confinement. Chem Commun (Camb) 2022; 58:6571-6585. [PMID: 35611956 DOI: 10.1039/d2cc01758j] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Exerting control on excited state processes has been a long-held goal in photochemistry. One approach to achieve control has been to mimic biological systems in Nature (e.g., photosynthesis) that has perfected it over millions of years by performing the reactions in highly organized assemblies such as membranes and proteins by restricting the freedom of reactants and directing them to pursue a select pathway. The duplication of this concept at a smaller scale in the laboratory involves the use of highly confined and organized assemblies as reaction containers. This article summarizes the studies in the author's laboratory using a synthetic, well-defined reaction container known as octa acid (OA). OA, unlike most commonly known cavitands, forms a capsule in water and remains closed during the lifetime of the excited states of included molecules. Thus, the described excited state chemistry occurs in a small space with hydrophobic characteristics. Examples where the photophysical and photochemical properties are dramatically altered, compared to that in organic solvents wherein the molecules are freely soluble, are presented to illustrate the value of a restricted environment in controlling the dynamics of molecules on an excited state surface. While the ground state complexation of the guest and host is controlled by well-known concepts of tight-fit, lock and key, complementarity, etc., free space around the guest is necessary for it to be able to undergo structural transformations in the excited state, where the time is short. This article highlights the role of free space during the dynamics of molecules within a confined, inflexible reaction cavity.
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2
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Zhu YJ, Zhao MK, Rebek J, Yu Y. Recent Advances in the Applications of Water-soluble Resorcinarene-based Deep Cavitands. Chemistry 2022; 11:e202200026. [PMID: 35701378 PMCID: PMC9197774 DOI: 10.1002/open.202200026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/04/2022] [Indexed: 11/08/2022]
Abstract
We review here the use of container molecules known as cavitands for performing organic reactions in water. Central to these endeavors are binding forces found in water, and among the strongest of these is the hydrophobic effect. We describe how the hydrophobic effect can be used to drive organic molecule guests into the confined space of cavitand hosts. Other forces participating in guest binding include cation-π interactions, chalcogen bonding and even hydrogen bonding to water involved in the host structure. The reactions of guests take advantage of their contortions in the limited space of the cavitands which enhance macrocyclic and site-selective processes. The cavitands are applied to the removal of organic pollutants from water and to the separation of isomeric guests. Progress is described on maneuvering the containers from stoichiometric participation to roles as catalysts.
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Affiliation(s)
- Yu-Jie Zhu
- Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444, China
| | - Ming-Kai Zhao
- Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444, China
| | - Julius Rebek
- Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444, China
| | - Yang Yu
- Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, Shanghai, 200444, China
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3
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Petroselli M, Rebek J, Yu Y. Highly Selective Radical Monoreduction of Dihalides Confined to a Dynamic Supramolecular Host. Chemistry 2021; 27:3284-3287. [PMID: 33301606 DOI: 10.1002/chem.202004953] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/03/2020] [Indexed: 12/26/2022]
Abstract
Reduction of alkyl dihalide guests (2-5 and 7) with trialkylsilanes (R3 SiH) was performed in water-soluble host 1 to investigate the effects of confinement on fast radical reactions (k≥103 m-1 s-1 ). High selectivity (>95 %) for mono-reduced products was observed for primary and secondary dihalide guests under mild conditions. The results highlight the importance of host-guest complexation rates to modulate the product selectivity in radical reactions.
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Affiliation(s)
- Manuel Petroselli
- Center for Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, 99 Shang-Da Road, Shanghai, 200444, P. R. China
| | - Julius Rebek
- The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute for Chemical Biology and Department of Chemistry, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Yang Yu
- Center for Supramolecular Chemistry & Catalysis and Department of Chemistry, College of Science, Shanghai University, 99 Shang-Da Road, Shanghai, 200444, P. R. China
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4
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Abstract
GEST NMR provides dynamic information on host–guest systems. It allows signal amplification of low concentrated complexes, detection of intermolecular interactions and quantification of guest exchange rates.
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Affiliation(s)
- Liat Avram
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
| | - Amnon Bar-Shir
- Faculty of Chemistry
- Weizmann Institute of Science
- 7610001 Rehovot
- Israel
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5
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Gupta S, Ramamurthy V. Characterization and Singlet Oxygen Oxidation of 1‐Alkyl Cyclohexenes Encapsulated Within a Water‐Soluble Organic Capsule. CHEMPHOTOCHEM 2018. [DOI: 10.1002/cptc.201800043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Shipra Gupta
- Department of Chemistry University of Miami Coral Gables, FL 33146 USA
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6
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Nazarova AA, Padnya PL, Gilyazeva AI, Khannanov AA, Evtugyn VG, Kutyreva MP, Klochkov VV, Stoikov II. Supramolecular motifs for the self-assembly of monosubstituted pillar[5]arenes with an amide fragment: from nanoparticles to supramolecular polymers. NEW J CHEM 2018. [DOI: 10.1039/c8nj03494j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The effects of solvents on the aggregation properties of novel monosubstituted pillar[5]arenes containing an N-alkylamide fragment have been investigated.
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Affiliation(s)
- A. A. Nazarova
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
- Institute of Physics
| | - P. L. Padnya
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
| | - A. I. Gilyazeva
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
| | - A. A. Khannanov
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
| | - V. G. Evtugyn
- Interdisciplinary Center for Analytical Microscopy
- Kazan Federal University
- Kazan
- Russian Federation
| | - M. P. Kutyreva
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
| | - V. V. Klochkov
- Institute of Physics
- Kazan Federal University
- Kazan
- Russian Federation
| | - I. I. Stoikov
- A.M. Butlerov Chemical Institute
- Kazan Federal University
- Kazan
- Russian Federation
- Institute of Physics
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7
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Mostovaya OA, Padnya PL, Vavilova AA, Shurpik DN, Khairutdinov BI, Mukhametzyanov TA, Khannanov AA, Kutyreva MP, Stoikov II. Tetracarboxylic acids on a thiacalixarene scaffold: synthesis and binding of dopamine hydrochloride. NEW J CHEM 2018. [DOI: 10.1039/c7nj03953k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tetracarboxylic acids based on thiacalix[4]arene in 1,3-alternate conformation quench fluorescence of dopamine hydrochloride according to the static mechanism.
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Affiliation(s)
- O. A. Mostovaya
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - P. L. Padnya
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - A. A. Vavilova
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - D. N. Shurpik
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - B. I. Khairutdinov
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
- Kazan Institute of Biochemistry and Biophysics
| | - T. A. Mukhametzyanov
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - A. A. Khannanov
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - M. P. Kutyreva
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
| | - I. I. Stoikov
- Kazan Federal University
- A.M. Butlerov Chemistry Institute
- Kazan
- Russian Federation
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8
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Choudhury R, Ramamurthy V. Understanding the complexation of aliphatic and aromatic acids guests with octa acid. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3795] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Rajib Choudhury
- Department of Chemistry; University of Miami; Coral Gables FL USA
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9
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Avram L, Wishard AD, Gibb BC, Bar‐Shir A. Quantifying Guest Exchange in Supramolecular Systems. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708726] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Liat Avram
- Department of Chemical Research Support The Weizmann Institute of Science 7610001 Rehovot Israel
| | | | - Bruce C. Gibb
- Department of Chemistry Tulane University New Orleans LA 70118 USA
| | - Amnon Bar‐Shir
- Department of Organic Chemistry The Weizmann Institute of Science 7610001 Rehovot Israel
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10
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Avram L, Wishard AD, Gibb BC, Bar-Shir A. Quantifying Guest Exchange in Supramolecular Systems. Angew Chem Int Ed Engl 2017; 56:15314-15318. [PMID: 28972281 DOI: 10.1002/anie.201708726] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Indexed: 11/08/2022]
Abstract
The ability to accurately determine and quantitatively evaluate kinetic phenomena associated with supramolecular assemblies, in real time, is key to a better understanding of their defined architectures and diverse functionalities. Therefore, analytical tools that can precisely assess a wide range of exchange rates within such systems are of considerable importance. This study demonstrates the ability to use an NMR approach based on saturation transfer for the determination of rates of guest exchange from molecular capsules. By using cavitands that assemble into distinct dimeric assemblies, we show that this approach, which we term guest exchange saturation transfer (GEST), allows the use of a conventional NMR setup to study and quantitatively assess a wide range of exchange rates, from 35 to more than 5000 s-1 .
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Affiliation(s)
- Liat Avram
- Department of Chemical Research Support, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Anthony D Wishard
- Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA
| | - Bruce C Gibb
- Department of Chemistry, Tulane University, New Orleans, LA, 70118, USA
| | - Amnon Bar-Shir
- Department of Organic Chemistry, The Weizmann Institute of Science, 7610001, Rehovot, Israel
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11
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Barnett JW, Gibb BC, Ashbaugh HS. Succession of Alkane Conformational Motifs Bound within Hydrophobic Supramolecular Capsular Assemblies. J Phys Chem B 2016; 120:10394-10402. [PMID: 27603416 DOI: 10.1021/acs.jpcb.6b06496] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
n-Alkane encapsulation experiments within dimeric octa-acid cavitand capsules in water reveal a succession of packing motifs from extended, to helical, to hairpin, to spinning top structures with increasing chain length. Here, we report a molecular simulation study of alkane conformational preferences within these host-guest assemblies to uncover the factors stabilizing distinct conformers. The simulated alkane conformers follow the trends inferred from 1H NMR experiments, while guest proton chemical shifts evaluated from Gauge Invariant Atomic Orbital calculations provide further evidence our simulations capture guest packing within these assemblies. Analysis of chain length and dihedral distributions indicates that packing under confinement to minimize nonpolar guest and host interior contact with water largely drives the transitions. Mean intramolecular distance maps and transfer free energy differences suggest the extended and helical motifs are members of a larger family of linear guest structures, for which the guest gauche population increases with increasing chain length to accommodate the chains within the complex. Breaks observed between the helical/hairpin and hairpin/spinning top motifs, on the other hand, indicate the hairpin and spinning top conformations are distinct from the linear family. Our results represent the first bridging of empirical and simulation data for flexible guests encapsulated within confined nanospaces, and constitute an effective strategy by which guest packing motifs within artificial or natural compartments can be rationalized and/or predicted a priori.
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Affiliation(s)
- J Wesley Barnett
- Department of Chemical and Biomolecular Engineering, Tulane University , New Orleans, Louisiana 70118, United States
| | - Bruce C Gibb
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Henry S Ashbaugh
- Department of Chemical and Biomolecular Engineering, Tulane University , New Orleans, Louisiana 70118, United States
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12
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Hillyer MB, Gibb CLD, Sokkalingam P, Jordan JH, Ioup SE, Mague JT, Gibb BC. Synthesis of Water-Soluble Deep-Cavity Cavitands. Org Lett 2016; 18:4048-51. [PMID: 27500699 DOI: 10.1021/acs.orglett.6b01903] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An efficient, four-step synthesis of a range of water-soluble, deep-cavity cavitands is presented. Key to this approach are octahalide derivatives (4, X = Cl or Br) that allow a range of water-solubilizing groups to be added to the outer surface of the core host structure. In many cases, the conversion of the starting dodecol (1) resorcinarene to the different cavitands avoids any chromatographic procedures.
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Affiliation(s)
- Matthew B Hillyer
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Corinne L D Gibb
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Punidha Sokkalingam
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Jacobs H Jordan
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | - Sarah E Ioup
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
| | | | - Bruce C Gibb
- Department of Chemistry, Tulane University , New Orleans, Louisiana 70118, United States
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13
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Abstract
Photochemistry along with life as we know it originated on earth billions of years ago. Supramolecular Photochemistry had its beginning when plants that sustain life began transforming water into oxygen by carrying out light initiated reactions within highly organized assemblies. Prompted by the efforts of J. Priestly (photosynthesis), F. Sestini, S. Cannizaro, and C. Liebermann (solid-state photochemistry of santonin, quinones, and cinnamic acid), orderly scientific investigations of the link between light absorption by matter and molecules and the chemical and physical consequences began in the mid-1700s. By 1970 when Molecular Photochemistry had matured, it was clear that controlling photochemical reactions by conventional methods of varying reaction parameters like temperature and pressure would be futile due to the photoreactions' very low activation energies and enthalpies. During the last 50 years, the excited state behavior of molecules has been successfully manipulated with the use of confining media and weak interactions between the medium and the reactant molecule. In this context, with our knowledge from experimentation with micelles, cyclodextrins (CD), cucurbitruils (CB), calixarenes (CA), Pd nanocage, crystals, and zeolites as media, we began about a decade ago to explore the use of a new water-soluble synthetic organic cavitand, octa acid (OA) as a reaction container. The uniqueness of OA as an organic cavitand lies in that two OA molecules form a closed hydrophobic capsule to encapsulate water-insoluble guest molecule(s). The ability to include a large number of guest molecules in OA has provided an opportunity to examine the excited state chemistry of organic molecules in a hydrophobic, confined environment. OA distinguishes itself from the well-known cavitands CD and CB by its active reaction cavity absorbing UV-radiation between 200 and 300 nm and serving as energy, electron, and hydrogen donor. The freedom of guest molecules in OA, between that in crystals and isotropic solution can be transformed into photoproducts selectivity. The results of our photochemical investigations elaborated in this Account demonstrate that OA with a medium sized cavity exerts better control on excited state processes than the more common and familiar organic hosts such as CD, CB, CA, and micelles. By examining the photochemistry of a number of molecules (olefins, carbonyls, aromatics and singlet oxygen) that undergo varied reactions (cleavage, cycloaddition, cis-trans isomerization, oxidation and cyclization) within OA capsule, we have demonstrated that the free space within the container, the capsule influenced conformation and preorientation of guest molecules, supramolecular steric control, and capsular dynamics contribute to the altered excited state behavior. In this Account, we have shown that photochemistry based on concepts of physical organic and supramolecular chemistry continues to be a discipline with unlimited potential. The future of supramolecular photochemistry lies in synthetic, materials, medicinal, and biological chemistries. Success in these areas depends on synthesizing well-designed water-soluble hosts that can emulate complex biological assemblies, organizing and examining the behavior of supramolecular assemblies on solid surfaces, rendering the photoreactions catalytic, and delivering encapsulated drugs in a targeted fashion.
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14
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Gibb CLD, Oertling EE, Velaga S, Gibb BC. Thermodynamic Profiles of Salt Effects on a Host–Guest System: New Insight into the Hofmeister Effect. J Phys Chem B 2015; 119:5624-38. [DOI: 10.1021/acs.jpcb.5b01708] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Corinne L. D. Gibb
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Estelle E. Oertling
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Santhosh Velaga
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
| | - Bruce C. Gibb
- Department
of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States
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15
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Gangemi CMA, Pappalardo A, Trusso Sfrazzetto G. Applications of supramolecular capsules derived from resorcin[4]arenes, calix[n]arenes and metallo-ligands: from biology to catalysis. RSC Adv 2015. [DOI: 10.1039/c5ra09364c] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This review summarizes supramolecular capsules based on resorcin[4]arenes, calix[n]arenes and metal–ligands, having concrete applications in biomedical field, catalysis and material science.
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Affiliation(s)
| | - Andrea Pappalardo
- Department of Chemical Sciences
- University of Catania
- 95125 Catania
- Italy
- I.N.S.T.M. UdR of Catania
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Ramamurthy V, Gupta S. Supramolecular photochemistry: from molecular crystals to water-soluble capsules. Chem Soc Rev 2015; 44:119-35. [DOI: 10.1039/c4cs00284a] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Photochemical and photophysical behavior of molecules in supramolecular assemblies are different and more selective than in gas and isotropic solution phases.
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Affiliation(s)
- V. Ramamurthy
- Department of Chemistry
- University of Miami
- Coral Gables
- USA
| | - Shipra Gupta
- Department of Chemistry
- University of Miami
- Coral Gables
- USA
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17
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Jagadesan P, Mondal B, Parthasarathy A, Rao VJ, Ramamurthy V. Photochemical reaction containers as energy and electron-transfer agents. Org Lett 2013; 15:1326-9. [PMID: 23451936 DOI: 10.1021/ol400267k] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two deep cavity cavitands, octa acid and resorcinol-capped octa acid, have been established to be good triplet energy donors in the excited state and electron donors in the ground state to excited acceptors. This property endows them the capacity to be "active" reaction containers. The above recognition provides opportunities to investigate the excited state chemistry of host-encapsulated guests without the use of secondary triplet energy and electron donors.
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18
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Choudhury R, Barman A, Prabhakar R, Ramamurthy V. Hydrocarbons depending on the chain length and head group adopt different conformations within a water-soluble nanocapsule: 1H NMR and molecular dynamics studies. J Phys Chem B 2012; 117:398-407. [PMID: 23215251 DOI: 10.1021/jp3090815] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In this study we have examined the conformational preference of phenyl-substituted hydrocarbons (alkanes, alkenes, and alkynes) of different chain lengths included within a confined space provided by a molecular capsule made of two host cavitands known by the trivial name "octa acid" (OA). One- and two-dimensional (1)H NMR experiments and molecular dynamics (MD) simulations were employed to probe the location and conformation of hydrocarbons within the OA capsule. In general, small hydrocarbons adopted a linear conformation while longer ones preferred a folded conformation. In addition, the extent of folding and the location of the end groups (methyl and phenyl) were dependent on the group (H(2)C-CH(2), HC═CH, and C≡C) adjacent to the phenyl group. In addition, the rotational mobility of the hydrocarbons within the capsule varied; for example, while phenylated alkanes tumbled freely, phenylated alkenes and alkynes resisted such a motion at room temperature. Combined NMR and MD simulation studies have confirmed that molecules could adopt conformations within confined spaces different from that in solution, opening opportunities to modulate chemical behavior of guest molecules.
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Affiliation(s)
- Rajib Choudhury
- Department of Chemistry, University of Miami, Coral Gables, Florida 33124, United States
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19
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Nakazawa J, Hagiwara J, Shimazaki Y, Tani F, Naruta Y. Synthesis, Characterization, and Small Hydrocarbon Encapsulation of Dicavitand-Porphyrins. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2012. [DOI: 10.1246/bcsj.20120107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jun Nakazawa
- Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University
| | - Jun Hagiwara
- Institute for Materials Chemistry and Engineering, Kyushu University
| | | | - Fumito Tani
- Institute for Materials Chemistry and Engineering, Kyushu University
| | - Yoshinori Naruta
- Institute for Materials Chemistry and Engineering, Kyushu University
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20
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Samanta SR, Parthasarathy A, Ramamurthy V. Supramolecular control during triplet sensitized geometric isomerization of stilbenes encapsulated in a water soluble organic capsule. Photochem Photobiol Sci 2012; 11:1652-60. [DOI: 10.1039/c2pp25115a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Da Silva JP, Kulasekharan R, Cordeiro C, Jockusch S, Turro NJ, Ramamurthy V. Capsular complexes of nonpolar guests with octa amine host detected in the gas phase. Org Lett 2011; 14:560-3. [PMID: 22195767 DOI: 10.1021/ol203139v] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nanocapsules, made up of the deep cavitand octa amine and several guests, were prepared in aqueous acidic solution and were found to be stable in the gas phase as detected by electrospray ionization mass spectrometry (ESI-MS). The observed gas phase host-guest complexes contained five positive charges and were associated with several acid molecules (HCl or HBr).
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Affiliation(s)
- José P Da Silva
- Centro de Investigação em Química do Algarve, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
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22
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Abstract
The use of light as a stimulus to control functional materials or nano-devices is appealing as it provides convenient control of triggering events where and when they are desired without introducing extra components to the system. Many photophysical and photochemical processes are extremely fast, giving rise to nearly instantaneous onset of events. However, these fast processes can be challenging to engineer into chemical systems. Supramolecular chemistry offers a convenient way to study and control photoprocesses. Given the reversible and self-programmed nature of modern host-guest systems, a modular approach can be considered in which different photoprocesses are coupled to obtain complex functions that emerge and are controlled solely by light inputs. In this review, we highlight recent examples of photoswitching and photophysics applied in the context of supramolecular host-guest systems, with a particular emphasis on resorcinarene based cavitands and hydrogen bonded capsules.
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Affiliation(s)
- Orion B Berryman
- Orion B. Berryman, Henry Dube and Julius Rebek Jr. The Skaggs Institute for Chemical Biology, The Scripps Research Institute 10550 North Torrey Pines Road, La Jolla, CA 92037 (USA)
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23
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Abstract
This critical review offers an overview of asymmetric electrocyclic processes, where diastereo- or enantioselectivity is a consequence of the influence of a chiral component (be it substrate or catalyst) on the electrocyclic bond-forming process (195 references).
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Affiliation(s)
- Sam Thompson
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
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24
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Abstract
An improved synthesis of a water-soluble deep-cavity cavitand (octa-acid, 1) is presented. Previously (Gibb, C. L. D. & Gibb, B. C., J. Am. Chem. Soc., 2004, 126, 11408-11409) we documented access to host 1 in eight (non-linear) steps starting from resorcinol; a synthesis that required four steps involving chromatographic purification. Here we reveal a modified synthesis of host 1. Consisting of seven (non-linear) steps, this new synthesis involves only one chromatographic step, and avoids a minor impurity observed in the original approach. This improved synthesis will therefore be useful for the laboratories that are investigating the properties of these types of host.
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Affiliation(s)
- Simin Liu
- Department of Chemistry, University of New Orleans New Orleans, LA 70148, USA
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Laughrey Z, Gibb BC. Water-soluble, self-assembling container molecules: an update. Chem Soc Rev 2011; 40:363-86. [DOI: 10.1039/c0cs00030b] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Parthasarathy A, Ramamurthy V. Role of free space and weak interactions on geometric isomerization of stilbenes held in a molecular container. Photochem Photobiol Sci 2011; 10:1455-62. [DOI: 10.1039/c1pp05035d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Liu S, Gan H, Hermann AT, Rick SW, Gibb BC. Kinetic resolution of constitutional isomers controlled by selective protection inside a supramolecular nanocapsule. Nat Chem 2010; 2:847-52. [PMID: 20861900 DOI: 10.1038/nchem.751] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/14/2010] [Indexed: 11/09/2022]
Abstract
The concept of self-assembling container molecules as yocto-litre reaction flasks is gaining prominence. However, the idea of using such containers as a means of protection is not well developed. Here, we illustrate this idea in the context of kinetic resolutions. Specifically, we report on the use of a water-soluble, deep-cavity cavitand to bring about kinetic resolutions within pairs of esters that otherwise cannot be resolved because they react at very similar rates. Resolution occurs because the presence of the cavitand leads to a competitive binding equilibrium in which the stronger binder primarily resides inside the host and the weaker binding ester primarily resides in the bulk hydrolytic medium. For the two families of ester examined, the observed kinetic resolutions were highest within the optimally fitting smaller esters.
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Affiliation(s)
- Simin Liu
- Department of Chemistry, University of New Orleans, New Orleans, Louisiana 70148, USA
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Kulasekharan R, Jayaraj N, Porel M, Choudhury R, Sundaresan AK, Parthasarathy A, Ottaviani MF, Jockusch S, Turro NJ, Ramamurthy V. Guest rotations within a capsuleplex probed by NMR and EPR techniques. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6943-6953. [PMID: 20055365 DOI: 10.1021/la904196g] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
With the help of (1)H NMR and EPR techniques, we have probed the dynamics of guest molecules included within a water-soluble deep cavity cavitand known by the trivial name octa acid. All guest molecules investigated here form 2:1 (host/guest) complexes in water, and two host molecules encapsulate the guest molecule by forming a closed capsule. We have probed the dynamics of the guest molecule within this closed container through (1)H NMR and EPR techniques. The timescales offered by these two techniques are quite different, millisecond and nanosecond, respectively. For EPR studies, paramagnetic nitroxide guest molecules and for (1)H NMR studies, a wide variety of structurally diverse neutral organic guest molecules were employed. The guest molecules freely rotate along their x axis (long molecular axis and magnetic axis) on the NMR timescale; however, their rotation is slowed with respect to that in water on the EPR timescale. Rotation along the x axis is dependent on the length of the alkyl chain attached to the nitroxide probe. Overall rotation along the y or z axis was very much dependent on the structure of the guest molecule. The guests investigated could be classified into three groups: (a) those that do not rotate along the y or z axis both at room and elevated (55 degrees C) temperatures, (b) those that rotate freely at room temperature, and (c) those that do not rotate at room temperature but do so at higher temperatures. One should note that rotation here refers to the NMR timescale and it is quite possible that all molecules may rotate at much longer timescales than the one probed here. A slight variation in structure alters the rotational mobility of the guest molecules.
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