1
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D'haese LCG, Daugey N, Pitrat D, Brotin T, Kapitán J, Liégeois V. Understanding the surrounding effects on Raman optical activity signatures of a chiral cage system: Cryptophane-PP-111. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 306:123484. [PMID: 37898056 DOI: 10.1016/j.saa.2023.123484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 09/18/2023] [Accepted: 10/01/2023] [Indexed: 10/30/2023]
Abstract
Cryptophane molecules are cage-like structures consisting in two hemispheres, each made of three benzene rings. These hemispheres are bound together with three O(CH2)nOlinkers of various lengths giving rise to a plethora of cryptophane derivatives. Moreover, they are able to encapsulate neutral guests: CH2Cl2, CHCl3, …; and charged species: Cs+, Tl+, …. Finally, they exhibit chiroptical properties thanks to the anti arrangement of the linkers between the hemispheres. This work focuses on the Raman optical activity (ROA) signatures of Cryptophane-111 (n=1 for each linker). More specifically, we aim at simulating accurately its ROA spectra with and without a xenon atom inside its cavity. Experimental data (Buffeteau et al., 2017) have already demonstrated the effect of the encapsulation in the low-wavenumbers region. To generate the initial structures, we rely on the novel Conformer-Rotamer Ensemble Sampling Tool (CREST) program, developed by S. Grimme and co-workers. This is required due to the flexibility provided by the linkers. The CREST algorithm seems promising and has already been used to sample the potential energy surface (PES) of target systems before the simulation of their vibrational spectroscopies (Eikås et al., 2022). We observe large similarities between the two sets of conformers (one with and one without Xe encapsulated), demonstrating the robustness of the CREST algorithm. For corresponding structures, the presence of xenon pushed the two hemispheres slightly further apart. After optimization at the DFT level, only one unique conformer has a Boltzmann population ratio greater than 1%, pointing out the relative rigidity of the cage. Based on this unique conformer, our simulations are in good agreement with the experimental data. Regarding xenon encapsulation, the (experimental and theoretical) ROA signatures at low wavenumbers are impacted: slight shifts in wavenumbers are observed as well as a decrease in relative ROA intensity for bands around 150 cm-1. The wavenumber shifts were very well reproduced by our simulations, but the experimental decrease in the ROA intensity was unfortunately not reproduced.
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Affiliation(s)
- Lou C G D'haese
- Theoretical Chemistry Laboratory (LCT), Namur Institute of Structured Matter (NISM), University of Namur, 5000 Namur, Belgium.
| | - Nicolas Daugey
- Groupe Spectroscopie Moléculaire (GSM), Institut des Sciences Moléculaires (ISM), UMR-5255 CNRS, University of Bordeaux, 33405 Talence, France
| | - Delphine Pitrat
- Laboratoire de Chimie de l'ENSL, UMR-5182 CNRS, University of Lyon, 69342 Lyon, France
| | - Thierry Brotin
- Laboratoire de Chimie de l'ENSL, UMR-5182 CNRS, University of Lyon, 69342 Lyon, France
| | - Josef Kapitán
- Department of Optics, Palacký University of Olomouc, 77146 Olomouc, Czech Republic
| | - Vincent Liégeois
- Theoretical Chemistry Laboratory (LCT), Namur Institute of Structured Matter (NISM), University of Namur, 5000 Namur, Belgium
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2
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Hilla P, Vaara J. NMR chemical shift of confined 129Xe: coordination number, paramagnetic channels and molecular dynamics in a cryptophane-A biosensor. Phys Chem Chem Phys 2023; 25:22719-22733. [PMID: 37606522 DOI: 10.1039/d3cp02695g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
Advances in hyperpolarisation and indirect detection have enabled the development of xenon nuclear magnetic resonance (NMR) biosensors (XBSs) for molecule-selective sensing in down to picomolar concentration. Cryptophanes (Crs) are popular cages for hosting the Xe "spy". Understanding the microscopic host-guest chemistry has remained a challenge in the XBS field. While early NMR computations of XBSs did not consider the important effects of host dynamics and explicit solvent, here we model the motionally averaged, relativistic NMR chemical shift (CS) of free Xe, Xe in a prototypic CrA cage and Xe in a water-soluble CrA derivative, each in an explicit H2O solvent, over system configurations generated at three different levels of molecular dynamics (MD) simulations. We confirm the "contact-type" character of the Xe CS, arising from the increased availability of paramagnetic channels, magnetic couplings between occupied and virtual orbitals through the short-ranged orbital hyperfine operator, when neighbouring atoms are in contact with Xe. Remarkably, the Xe CS in the present, highly dynamic and conformationally flexible situations is found to depend linearly on the coordination number of the Xe atom. We interpret the high- and low-CS situations in terms of the magnetic absorption spectrum and choose our preference among the used MD methods based on comparison with the experimental CS. We check the role of spin-orbit coupling by comparing with fully relativistic CS calculations. The study outlines the computational workflow required to realistically model the CS of Xe confined in dynamic cavity structures under experimental conditions, and contributes to microscopic understanding of XBSs.
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Affiliation(s)
- Perttu Hilla
- NMR Research Unit, P.O. Box 3000, FI-90014 University of Oulu, Finland.
| | - Juha Vaara
- NMR Research Unit, P.O. Box 3000, FI-90014 University of Oulu, Finland.
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3
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Xenon Induces Its Own Preferred Heterochiral Host from Exclusive Homochiral Assembly. J Am Chem Soc 2022; 144:22884-22889. [PMID: 36480928 DOI: 10.1021/jacs.2c12202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Xenon binding represents a formidable challenge, and efficient hosts remain rare. Here we report our findings that while enantiomeric bis(urea)-bis(thiourea) macrocycles form exclusive homochiral dimeric assemblies, xenon is able to overcome the narcissism and induces an otherwise-nonobservable heterochiral assembly as its preferred host. An experimental approach and fitting model were developed to obtain binding constants associated with the invisible assembly species. The determined xenon binding affinity with the heterochiral capsule reaches 1600 M-1, which is 15 times higher than that with the homochiral capsule and represents the highest record for an assembled host. The origin of the large difference in xenon affinity between the two subtle diastereotopic assemblies was revealed by single-crystal analysis. In the heterochiral capsule with S4 symmetry, the xenon atom is more tightly enclosed by van der Waals surroundings of the four thiourea groups arranged in a spherical cross-array, superior to the antiparallel array in the homochiral capsule with D2 symmetry.
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4
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Exploring 129Xe NMR parameters for structural investigation of biomolecules: relativistic, solvent, and thermal effects. J Mol Model 2022; 28:372. [DOI: 10.1007/s00894-022-05365-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022]
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5
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Hilla P, Vaara J. Energetics and exchange of xenon and water in a prototypic cryptophane-A biosensor structure. Phys Chem Chem Phys 2022; 24:17946-17950. [PMID: 35748333 DOI: 10.1039/d2cp01889f] [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
A microscopic description of the energetics and dynamics of xenon NMR biosensors can be experimentally difficult to achieve. We conduct molecular dynamics and metadynamics simulations of a prototypical Xe@cryptophane-A biosensor in an explicit water solvent. We compute the non-covalent Xe binding energy, identify the complexation mechanism of Xe, and calculate the exchange dynamics of water molecules between the solution and the host. Three distinct, hitherto unreported Xe exchange processes are identified, and water molecules initialize each one. The obtained binding energies support the existing literature. The residence times and energetics of water guests are reported. An empty host does not remain empty, but is occupied by water. The results contribute to the understanding and development of Xe biosensors based on cryptophane derivatives and alternative host structures.
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Affiliation(s)
- Perttu Hilla
- NMR Research Unit, P.O. Box 3000, FI-90014 University of Oulu, Finland.
| | - Juha Vaara
- NMR Research Unit, P.O. Box 3000, FI-90014 University of Oulu, Finland.
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6
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Nilam M, Hennig A. Enzyme assays with supramolecular chemosensors - the label-free approach. RSC Adv 2022; 12:10725-10748. [PMID: 35425010 PMCID: PMC8984408 DOI: 10.1039/d1ra08617k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/30/2022] [Indexed: 12/20/2022] Open
Abstract
Enzyme activity measurements are essential for many research areas, e.g., for the identification of inhibitors in drug discovery, in bioengineering of enzyme mutants for biotechnological applications, or in bioanalytical chemistry as parts of biosensors. In particular in high-throughput screening (HTS), sensitive optical detection is most preferred and numerous absorption and fluorescence spectroscopy-based enzyme assays have been developed, which most frequently require time-consuming fluorescent labelling that may interfere with biological recognition. The use of supramolecular chemosensors, which can specifically signal analytes with fluorescence-based read-out methods, affords an attractive and label-free alternative to more established enzyme assays. We provide herein a comprehensive review that summarizes the current state-of-the-art of supramolecular enzyme assays ranging from early examples with covalent chemosensors to the most recent applications of supramolecular tandem enzyme assays, which utilize common and often commercially available combinations of macrocyclic host molecules (e.g. cyclodextrins, calixarenes, and cucurbiturils) and fluorescent dyes as self-assembled reporter pairs for assaying enzyme activity.
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Affiliation(s)
- Mohamed Nilam
- Department of Biology/Chemistry, Center for Cellular Nanoanalytics (CellNanOs), Universität Osnabrück Barbarastr. 7 D-49076 Osnabrück Germany
| | - Andreas Hennig
- Department of Biology/Chemistry, Center for Cellular Nanoanalytics (CellNanOs), Universität Osnabrück Barbarastr. 7 D-49076 Osnabrück Germany
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Pavlović RZ, Lalisse RF, Hansen AL, Waudby CA, Lei Z, Güney M, Wang X, Hadad CM, Badjić JD. From Selection to Instruction and Back: Competing Conformational Selection and Induced Fit Pathways in Abiotic Hosts. Angew Chem Int Ed Engl 2021; 60:19942-19948. [PMID: 34125989 DOI: 10.1002/anie.202107091] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Indexed: 12/15/2022]
Abstract
Two limiting cases of molecular recognition, induced fit (IF) and conformational selection (CS), play a central role in allosteric regulation of natural systems. The IF paradigm states that a substrate "instructs" the host to change its shape after complexation, while CS asserts that a guest "selects" the optimal fit from an ensemble of preexisting host conformations. With no studies that quantitatively address the interplay of two limiting pathways in abiotic systems, we herein and for the first time describe the way by which twisted capsule M-1, encompassing two conformers M-1(+) and M-1(-), trap CX4 (X=Cl, Br) to give CX4 ⊂M-1(+) and CX4 ⊂M-1(-), with all four states being in thermal equilibrium. With the assistance of 2D EXSY, we found that CBr4 would, at its lower concentrations, bind M-1 via a M-1(+)→M-1(-)→CBr4 ⊂M-1(-) pathway corresponding to conformational selection. For M-1 complexing CCl4 though, data from 2D EXSY measurements and 1D NMR line-shape analysis suggested that lower CCl4 concentrations would favor CS while the IF pathway prevailed at higher proportions of the guest. Since CS and IF are not mutually exclusive, we reason that our work sets the stage for characterizing the dynamics of a wide range of already existing hosts to broaden our fundamental understanding of their action. The objective is to master the way in which encapsulation takes place for designing novel and allosteric sequestering agents, catalysts and chemosensors akin to those found in nature.
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Affiliation(s)
- Radoslav Z Pavlović
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Remy F Lalisse
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Alexandar L Hansen
- Campus Chemical Instrument Center, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Christopher A Waudby
- Institute of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK
| | - Zhiquan Lei
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Murat Güney
- Agri Ibrahim Çeçen University, Department of Chemistry, 04100, Agri, Turkey
| | - Xiuze Wang
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Christopher M Hadad
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
| | - Jovica D Badjić
- Department of Chemistry & Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH, 43210, USA
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8
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Pavlović RZ, Lalisse RF, Hansen AL, Waudby CA, Lei Z, Güney M, Wang X, Hadad CM, Badjić JD. From Selection to Instruction and Back: Competing Conformational Selection and Induced Fit Pathways in Abiotic Hosts. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Radoslav Z. Pavlović
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Remy F. Lalisse
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Alexandar L. Hansen
- Campus Chemical Instrument Center The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Christopher A. Waudby
- Institute of Structural and Molecular Biology University College London London WC1E 6BT UK
| | - Zhiquan Lei
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Murat Güney
- Agri Ibrahim Çeçen University Department of Chemistry 04100 Agri Turkey
| | - Xiuze Wang
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Christopher M. Hadad
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
| | - Jovica D. Badjić
- Department of Chemistry & Biochemistry The Ohio State University 100 West 18th Avenue Columbus OH 43210 USA
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9
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Xenon binding by a tight yet adaptive chiral soft capsule. Nat Commun 2020; 11:6257. [PMID: 33288758 PMCID: PMC7721739 DOI: 10.1038/s41467-020-20081-8] [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: 06/11/2020] [Accepted: 11/11/2020] [Indexed: 11/08/2022] Open
Abstract
Xenon binding has attracted interest due to the potential for xenon separation and emerging applications in magnetic resonance imaging. Compared to their covalent counterparts, assembled hosts that are able to effectively bind xenon are rare. Here, we report a tight yet soft chiral macrocycle dimeric capsule for efficient and adaptive xenon binding in both crystal form and solution. The chiral bisurea-bisthiourea macrocycle can be easily synthesized in multi-gram scale. Through assembly, the flexible macrocycles are locked in a bowl-shaped conformation and buckled to each other, wrapping up a tight, completely sealed yet adjustable cavity suitable for xenon, with a very high affinity for an assembled host. A slow-exchange process and drastic spectral changes are observed in both 1H and 129Xe NMR. With the easy synthesis, modification and reversible characteristics, we believe the robust yet adaptive assembly system may find applications in xenon sequestration and magnetic resonance imaging-based biosensing.
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10
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Jayapaul J, Schröder L. Nanoparticle-Based Contrast Agents for 129Xe HyperCEST NMR and MRI Applications. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:9498173. [PMID: 31819739 PMCID: PMC6893250 DOI: 10.1155/2019/9498173] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/15/2019] [Indexed: 02/06/2023]
Abstract
Spin hyperpolarization techniques have enabled important advancements in preclinical and clinical MRI applications to overcome the intrinsic low sensitivity of nuclear magnetic resonance. Functionalized xenon biosensors represent one of these approaches. They combine two amplification strategies, namely, spin exchange optical pumping (SEOP) and chemical exchange saturation transfer (CEST). The latter one requires host structures that reversibly bind the hyperpolarized noble gas. Different nanoparticle approaches have been implemented and have enabled molecular MRI with 129Xe at unprecedented sensitivity. This review gives an overview of the Xe biosensor concept, particularly how different nanoparticles address various critical aspects of gas binding and exchange, spectral dispersion for multiplexing, and targeted reporter delivery. As this concept is emerging into preclinical applications, comprehensive sensor design will be indispensable in translating the outstanding sensitivity potential into biomedical molecular imaging applications.
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Affiliation(s)
- Jabadurai Jayapaul
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
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11
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Pizzi A, Ozores HL, Calvelo M, García‐Fandiño R, Amorín M, Demitri N, Terraneo G, Bracco S, Comotti A, Sozzani P, Bezuidenhout CX, Metrangolo P, Granja JR. Tight Xenon Confinement in a Crystalline Sandwich‐like Hydrogen‐Bonded Dimeric Capsule of a Cyclic Peptide. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201906599] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Andrea Pizzi
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Haxel Lionel Ozores
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Martín Calvelo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Rebeca García‐Fandiño
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Manuel Amorín
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Nicola Demitri
- Elettra—Sincrotrone Trieste S.S. 14 Km 163.5 in Area Science Park 34149 Basovizza— Trieste Italy
| | - Giancarlo Terraneo
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Silvia Bracco
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Angiolina Comotti
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Piero Sozzani
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Charl X. Bezuidenhout
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Pierangelo Metrangolo
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Juan R. Granja
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
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12
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Pizzi A, Ozores HL, Calvelo M, García‐Fandiño R, Amorín M, Demitri N, Terraneo G, Bracco S, Comotti A, Sozzani P, Bezuidenhout CX, Metrangolo P, Granja JR. Tight Xenon Confinement in a Crystalline Sandwich‐like Hydrogen‐Bonded Dimeric Capsule of a Cyclic Peptide. Angew Chem Int Ed Engl 2019; 58:14472-14476. [PMID: 31418497 DOI: 10.1002/anie.201906599] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 08/14/2019] [Indexed: 01/21/2023]
Affiliation(s)
- Andrea Pizzi
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Haxel Lionel Ozores
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Martín Calvelo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Rebeca García‐Fandiño
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Manuel Amorín
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
| | - Nicola Demitri
- Elettra—Sincrotrone Trieste S.S. 14 Km 163.5 in Area Science Park 34149 Basovizza— Trieste Italy
| | - Giancarlo Terraneo
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Silvia Bracco
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Angiolina Comotti
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Piero Sozzani
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Charl X. Bezuidenhout
- Department of Materials Science University of Milano Bicocca Via R. Cozzi 55 20125 Milan Italy
| | - Pierangelo Metrangolo
- Laboratory of Supramolecular and Bio-Nanomaterials, (SupraBioNanoLab) Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta” Politecnico di Milano 20131 Milano Italy
| | - Juan R. Granja
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS) and Departamento de Química Orgánica Universidad de Santiago de Compostela 15782 Santiago de Compostela Spain
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13
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Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
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Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
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14
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Korchak S, Riemer T, Kilian W, Mitschang L. Quantitative biosensor detection by chemically exchanging hyperpolarized 129Xe. Phys Chem Chem Phys 2018; 20:1800-1808. [DOI: 10.1039/c7cp07051a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantitative modeling and evaluation of biosensor detection by hyperpolarized 129Xe chemical exchange saturation transfer (Hyper-CEST).
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Affiliation(s)
- S. Korchak
- Physikalisch-Technische Bundesanstalt (PTB)
- 10587 Berlin
- Germany
| | - T. Riemer
- University of Leipzig
- Medical Department
- Institute of Medical Physics and Biophysics
- 04107 Leipzig
- Germany
| | - W. Kilian
- Physikalisch-Technische Bundesanstalt (PTB)
- 10587 Berlin
- Germany
| | - L. Mitschang
- Physikalisch-Technische Bundesanstalt (PTB)
- 10587 Berlin
- Germany
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15
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Demissie TB, Ruud K, Hansen JH. Cryptophanes for Methane and Xenon Encapsulation: A Comparative Density Functional Theory Study of Binding Properties and NMR Chemical Shifts. J Phys Chem A 2017; 121:9669-9677. [PMID: 29178799 DOI: 10.1021/acs.jpca.7b10595] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The host-guest chemistry of cryptophanes is an active research area because of its applications in sensor design, targeting small molecules and atoms in environmental and medical sciences. As such, the computational prediction of binding energies and nuclear magnetic resonance (NMR) properties of different cryptophane complexes are of interest to both theoreticians and experimentalists working in host-guest based sensor development. Herein we present a study of 10 known and some newly proposed cryptophanes using density functional theory (DFT) calculations. We benchmark the description of nonbonding interactions by different DFT functionals against spin-component-scaled, second-order Møller-Plesset theory (SCS-MP2) and predict novel host molecules with enhanced affinity toward methane and Xenon, two representative systems of high interest. We demonstrate the power and limitations of the different computational methods in describing the binding and NMR properties of these established and novel host systems. The results show the importance of including dispersion corrections in the DFT functionals. The overall analysis of the dispersion corrections indicated that results obtained from pure DFT functionals should be used cautiously when conclusions are drawn for molecular systems with considerable weak interactions. Proposed analogues of cryptophane-A, where the alkoxy bridges are replaced by alkyl chains, are predicted to display enhanced affinity toward both methane and Xenon.
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Affiliation(s)
- Taye B Demissie
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway , 9037 Tromsø, Norway.,Organic Chemistry Group, Department of Chemistry, UiT The Arctic University of Norway , 9037 Tromsø, Norway
| | - Kenneth Ruud
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway , 9037 Tromsø, Norway
| | - Jørn H Hansen
- Organic Chemistry Group, Department of Chemistry, UiT The Arctic University of Norway , 9037 Tromsø, Norway
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Berthault P, Boutin C, Léonce E, Jeanneau E, Brotin T. Role of the Methoxy Groups in Cryptophanes for Complexation of Xenon: Conformational Selection Evidence from 129
Xe-1
H NMR SPINOE Experiments. Chemphyschem 2017; 18:1561-1568. [DOI: 10.1002/cphc.201700266] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Patrick Berthault
- NIMBE, CEA, CNRS; Université de Paris Saclay, CEA Saclay; 91191 Gif-sur-Yvette France
| | - Céline Boutin
- NIMBE, CEA, CNRS; Université de Paris Saclay, CEA Saclay; 91191 Gif-sur-Yvette France
| | - Estelle Léonce
- NIMBE, CEA, CNRS; Université de Paris Saclay, CEA Saclay; 91191 Gif-sur-Yvette France
| | - Erwann Jeanneau
- Centre de Diffractométrie Henri Longchambon; Université de Lyon 1; 5 rue la Doua 69100 Villeurbanne France
| | - Thierry Brotin
- Laboratoire de Chimie de L'ENS LYON (UMR 5182); Ecole Normale Supérieure de Lyon; 46, Allée D'Italie 69364 Lyon cedex 07 France
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17
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Barskiy DA, Coffey AM, Nikolaou P, Mikhaylov DM, Goodson BM, Branca RT, Lu GJ, Shapiro MG, Telkki VV, Zhivonitko VV, Koptyug IV, Salnikov OG, Kovtunov KV, Bukhtiyarov VI, Rosen MS, Barlow MJ, Safavi S, Hall IP, Schröder L, Chekmenev EY. NMR Hyperpolarization Techniques of Gases. Chemistry 2017; 23:725-751. [PMID: 27711999 PMCID: PMC5462469 DOI: 10.1002/chem.201603884] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Indexed: 01/09/2023]
Abstract
Nuclear spin polarization can be significantly increased through the process of hyperpolarization, leading to an increase in the sensitivity of nuclear magnetic resonance (NMR) experiments by 4-8 orders of magnitude. Hyperpolarized gases, unlike liquids and solids, can often be readily separated and purified from the compounds used to mediate the hyperpolarization processes. These pure hyperpolarized gases enabled many novel MRI applications including the visualization of void spaces, imaging of lung function, and remote detection. Additionally, hyperpolarized gases can be dissolved in liquids and can be used as sensitive molecular probes and reporters. This Minireview covers the fundamentals of the preparation of hyperpolarized gases and focuses on selected applications of interest to biomedicine and materials science.
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Affiliation(s)
- Danila A Barskiy
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | - Aaron M Coffey
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | - Panayiotis Nikolaou
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
| | | | - Boyd M Goodson
- Southern Illinois University, Department of Chemistry and Biochemistry, Materials Technology Center, Carbondale, IL, 62901, USA
| | - Rosa T Branca
- Department of Physics and Astronomy, Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - George J Lu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Mikhail G Shapiro
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | | | - Vladimir V Zhivonitko
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Igor V Koptyug
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Oleg G Salnikov
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Kirill V Kovtunov
- International Tomography Center SB RAS, 630090, Novosibirsk, Russia
- Novosibirsk State University, Pirogova St. 2, 630090, Novosibirsk, Russia
| | - Valerii I Bukhtiyarov
- Boreskov Institute of Catalysis SB RAS, 5 Acad. Lavrentiev Pr., 630090, Novosibirsk, Russia
| | - Matthew S Rosen
- MGH/A.A. Martinos Center for Biomedical Imaging, Boston, MA, 02129, USA
| | - Michael J Barlow
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Shahideh Safavi
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Ian P Hall
- Respiratory Medicine Department, Queen's Medical Centre, University of Nottingham Medical School, Nottingham, NG7 2UH, UK
| | - Leif Schröder
- Molecular Imaging, Department of Structural Biology, Leibniz-Institut für Molekulare Pharmakologie (FMP), 13125, Berlin, Germany
| | - Eduard Y Chekmenev
- Department of Radiology, Department of Biomedical Engineering, Department of Physics, Vanderbilt-Ingram Cancer Center (VICC), Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, 37232, USA
- Russian Academy of Sciences, 119991, Moscow, Russia
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Robinson JR, Qiao Y, Gu J, Carroll PJ, Walsh PJ, Schelter EJ. The role of dynamic ligand exchange in the oxidation chemistry of cerium(iii). Chem Sci 2016; 7:4537-4547. [PMID: 30155100 PMCID: PMC6016327 DOI: 10.1039/c5sc04897d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 03/22/2016] [Indexed: 01/09/2023] Open
Abstract
We report the exchange processes and reactivity of 1-Ce(het), which establish the effects of ligand redistribution and ligand reorganization in CeIII oxidation chemistry.
The CeIII/IV couple is useful for many applications in organic, inorganic, and materials chemistry. However, attaining a general method to access both oxidations states through reversible solution redox chemistry remains challenging. Herein we report the synthesis, characterization, and oxidation chemistry of the novel Ce/Li REMB heterochiral diastereomer, 1-Ce(het). The solution exchange processes of 1-RE(het) (RE = Ce and Yb) were investigated to estimate rates of ligand and cation exchange relevant in homochiral and heterochiral frameworks. A detailed mechanistic investigation following the solution dynamics of 1-Ce(het) revealed reactivity controlled both by ligand reorganization and redistribution processes. Ligand reorganization was responsible for the kinetics associated with the chemical oxidation reaction, whereas ligand redistribution and exchange dictated the isolated products.
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Affiliation(s)
- Jerome R Robinson
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Yusen Qiao
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Jun Gu
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Patrick J Carroll
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Patrick J Walsh
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
| | - Eric J Schelter
- P. Roy and Diana T. Vagelos Laboratories , Department of Chemistry , University of Pennsylvania , Philadelphia , PA 19104 , USA . ;
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Chapellet LL, Cochrane JR, Mari E, Boutin C, Berthault P, Brotin T. Synthesis of Cryptophanes with Two Different Reaction Sites: Chemical Platforms for Xenon Biosensing. J Org Chem 2015; 80:6143-51. [PMID: 26020365 DOI: 10.1021/acs.joc.5b00653] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report the synthesis of new water-soluble cryptophane host molecules that can be used for the preparation of (129)Xe NMR-based biosensors. We show that the cryptophane-223 skeleton can be modified to introduce a unique secondary alcohol to the propylenedioxy linker. This chemical functionality can then be exploited to introduce a functional group that is different from the six chemical groups attached to the aromatic rings. In this approach, the generation of a statistical mixture when trying to selectively functionalize a symmetrical host molecule is eliminated, which enables the efficient large-scale production of new cryptophanes that can be used as chemical platforms ready to use for the preparation of xenon biosensors. To illustrate this approach, two molecular platforms have been prepared, and the ability of these new derivatives to bind xenon has been investigated.
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Affiliation(s)
- Laure-Lise Chapellet
- †Laboratoire de Chimie de l'ENS LYON, UMR 5182 - CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - James R Cochrane
- †Laboratoire de Chimie de l'ENS LYON, UMR 5182 - CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
| | - Emilie Mari
- ‡Laboratoire Structure et Dynamique par Résonance Magnétique, CEA Saclay, IRAMIS, NIMBE UMR CEA/CNRS 3685, 91191 Gif sur Yvette, France
| | - Céline Boutin
- ‡Laboratoire Structure et Dynamique par Résonance Magnétique, CEA Saclay, IRAMIS, NIMBE UMR CEA/CNRS 3685, 91191 Gif sur Yvette, France
| | - Patrick Berthault
- ‡Laboratoire Structure et Dynamique par Résonance Magnétique, CEA Saclay, IRAMIS, NIMBE UMR CEA/CNRS 3685, 91191 Gif sur Yvette, France
| | - Thierry Brotin
- †Laboratoire de Chimie de l'ENS LYON, UMR 5182 - CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon, France
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Robinson JR, Gu J, Carroll PJ, Schelter EJ, Walsh PJ. Exchange Processes in Shibasaki’s Rare Earth Alkali Metal BINOLate Frameworks and Their Relevance in Multifunctional Asymmetric Catalysis. J Am Chem Soc 2015; 137:7135-44. [DOI: 10.1021/jacs.5b02201] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jerome R. Robinson
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Jun Gu
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Carroll
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Patrick J. Walsh
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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21
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Korchak S, Kilian W, Mitschang L. Degeneracy in cryptophane–xenon complex formation in aqueous solution. Chem Commun (Camb) 2015; 51:1721-4. [DOI: 10.1039/c4cc08601e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Degenerate exchange prevails in the cryptophane-A–xenon host–guest system in aqueous solution.
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Affiliation(s)
- Sergey Korchak
- Physikalisch-Technische Bundesanstalt
- Division of Medical Physics and Metrological Information Technology
- 10587 Berlin
- Germany
| | - Wolfgang Kilian
- Physikalisch-Technische Bundesanstalt
- Division of Medical Physics and Metrological Information Technology
- 10587 Berlin
- Germany
| | - Lorenz Mitschang
- Physikalisch-Technische Bundesanstalt
- Division of Medical Physics and Metrological Information Technology
- 10587 Berlin
- Germany
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22
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Bai Y, Hill PA, Dmochowski IJ. Utilizing a water-soluble cryptophane with fast xenon exchange rates for picomolar sensitivity NMR measurements. Anal Chem 2012; 84:9935-41. [PMID: 23106513 DOI: 10.1021/ac302347y] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hyperpolarized (129)Xe chemical exchange saturation transfer ((129)Xe Hyper-CEST) NMR is a powerful technique for the ultrasensitive, indirect detection of Xe host molecules (e.g., cryptophane-A). Irradiation at the appropriate Xe-cryptophane resonant radio frequency results in relaxation of the bound hyperpolarized (129)Xe and rapid accumulation of depolarized (129)Xe in bulk solution. The cryptophane effectively "catalyzes" this process by providing a unique molecular environment for spin depolarization to occur, while allowing xenon exchange with the bulk solution during the hyperpolarized lifetime (T(1) ≈ 1 min). Following this scheme, a triacetic acid cryptophane-A derivative (TAAC) was indirectly detected at 1.4 picomolar concentration at 320 K in aqueous solution, which is the record for a single-unit xenon host. To investigate this sensitivity enhancement, the xenon binding kinetics of TAAC in water was studied by NMR exchange lifetime measurement. At 297 K, k(on) ≈ 1.5 × 10(6) M(-1) s(-1) and k(off) = 45 s(-1), which represent the fastest Xe association and dissociation rates measured for a high-affinity, water-soluble xenon host molecule near rt. NMR line width measurements provided similar exchange rates at rt, which we assign to solvent-Xe exchange in TAAC. At 320 K, k(off) was estimated to be 1.1 × 10(3) s(-1). In Hyper-CEST NMR experiments, the rate of (129)Xe depolarization achieved by 14 pM TAAC in the presence of radio frequency (RF) pulses was calculated to be 0.17 μM·s(-1). On a per cryptophane basis, this equates to 1.2 × 10(4)(129)Xe atoms s(-1) (or 4.6 × 10(4) Xe atoms s(-1), all Xe isotopes), which is more than an order of magnitude faster than k(off), the directly measurable Xe-TAAC exchange rate. This compels us to consider multiple Xe exchange processes for cryptophane-mediated bulk (129)Xe depolarization, which provide at least 10(7)-fold sensitivity enhancements over directly detected hyperpolarized (129)Xe NMR signals.
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Affiliation(s)
- Yubin Bai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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23
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Han XN, Chen JM, Huang ZT, Zheng QY. Synthesis of Cyclotriveratrylene-Phenylacetylene Derivatives and a Photophysical Investigation of Rigid Conjugated Cyclotriveratrylene Dendrimers. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Ilczyszyn M, Selent M, Ilczyszyn MM. Participation of Xenon Guest in Hydrogen Bond Network of β-Hydroquinone Crystal. J Phys Chem A 2012; 116:3206-14. [DOI: 10.1021/jp210670k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marek Ilczyszyn
- Faculty of Chemistry, Wrocław University, 50-383 Wrocław,
Joliot Curie 14, Poland
| | - Marcin Selent
- Faculty of Chemistry, Wrocław University, 50-383 Wrocław,
Joliot Curie 14, Poland
- Department of Physics, University of Oulu, 90014 Oulu, Finland
| | - Maria M. Ilczyszyn
- Faculty of Chemistry, Wrocław University, 50-383 Wrocław,
Joliot Curie 14, Poland
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26
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Brotin T, Montserret R, Bouchet A, Cavagnat D, Linares M, Buffeteau T. High Affinity of Water-Soluble Cryptophanes for Cesium Cations. J Org Chem 2012; 77:1198-201. [DOI: 10.1021/jo202259r] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Thierry Brotin
- Laboratoire de Chimie de l′ENS-LYON
(UMR 5182-CNRS), Ecole Normale Supérieure de Lyon, 46 Allée d’Italie, 69364 Lyon 07, France
| | - Roland Montserret
- Institut de Biologie et Chimie
des Protéines (UMR 5086-CNRS), BMSSI, Université de Lyon 1, 7 Passage du Vercors, 69367 Lyon, France
| | - Aude Bouchet
- Institut des Sciences Moléculaires
(UMR 5255-CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
| | - Dominique Cavagnat
- Institut des Sciences Moléculaires
(UMR 5255-CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
| | - Mathieu Linares
- Department of Theoretical Chemistry,
School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden
| | - Thierry Buffeteau
- Institut des Sciences Moléculaires
(UMR 5255-CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
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Bouchet A, Brotin T, Linares M, Ågren H, Cavagnat D, Buffeteau T. Conformational Effects Induced by Guest Encapsulation in an Enantiopure Water-Soluble Cryptophane. J Org Chem 2011; 76:1372-83. [DOI: 10.1021/jo102350g] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Aude Bouchet
- Institut des Sciences Moléculaires (UMR 5255 − CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
| | - Thierry Brotin
- Laboratoire de Chimie de l’ENS-LYON (UMR 5182 − CNRS), Ecole Normale Supérieure de Lyon, 46 Allée d’Italie, 69364 Lyon 07, France
| | - Mathieu Linares
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden
| | - Hans Ågren
- Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, S-106 91 Stockholm, Sweden
| | - Dominique Cavagnat
- Institut des Sciences Moléculaires (UMR 5255 − CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
| | - Thierry Buffeteau
- Institut des Sciences Moléculaires (UMR 5255 − CNRS), Université Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France
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Berthault P, Desvaux H, Wendlinger T, Gyejacquot M, Stopin A, Brotin T, Dutasta JP, Boulard Y. Effect of pH and Counterions on the Encapsulation Properties of Xenon in Water-Soluble Cryptophanes. Chemistry 2010; 16:12941-6. [DOI: 10.1002/chem.201001170] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bouchet A, Brotin T, Cavagnat D, Buffeteau T. Induced Chiroptical Changes of a Water-Soluble Cryptophane by Encapsulation of Guest Molecules and Counterion Effects. Chemistry 2010; 16:4507-18. [PMID: 20235244 DOI: 10.1002/chem.200902740] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Indexed: 11/07/2022]
Affiliation(s)
- Aude Bouchet
- Institut des Sciences Moléculaires (CNRS - UMR5255), Université Bordeaux 1, 351, Cours de la Libération, 33405 Talence (France), Fax: (+33) 540008402
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Chaffee KE, Fogarty HA, Brotin T, Goodson BM, Dutasta JP. Encapsulation of small gas molecules by cryptophane-111 in organic solution. 1. Size- and shape-selective complexation of simple hydrocarbons. J Phys Chem A 2010; 113:13675-84. [PMID: 19883101 DOI: 10.1021/jp903452k] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reversible trapping of small hydrocarbons and other gases by cryptophane-111 (1) in organic solution was characterized with variable-temperature (1)H NMR spectroscopy. Characteristic spectral changes observed upon guest binding allowed kinetic and thermodynamic data to be readily extracted, permitting quantification and comparison of different host-guest interactions. Previous work (J. Am. Chem. Soc. 2007, 129, 10332) demonstrated that 1, the smallest cryptophane to date, forms a complex with xenon with remarkably high affinity. Presently, it is shown that 1 also exhibits slow exchange dynamics with methane at reduced temperatures (delta(bound) = -5.2 ppm) with an association constant K(a) = 148 M(-1) at 298 K. In contrast, ethane and ethylene are poorly recognized by 1 with K(a) values of only 2 M(-1) and 22 M(-1), respectively; moreover, chloromethane (whose molecular volume is similar to that of xenon, approximately 42 A(3)) is not observed to bind to 1. Separately, molecular hydrogen (H(2)) gas is observed to bind 1, but in contrast to other ligands presently studied, H(2) complexation is spectrally manifested by fast exchange throughout virtually the entire range of available conditions, as well as by a complex dependence of the guest (1)H resonance frequency upon temperature and host concentration. Taken together, these results establish 1 as a selective host for small gases, with implications for the design of size- and geometry-selective sensors targeted for various gas molecules.
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Affiliation(s)
- Kathleen E Chaffee
- Department of Chemistry and Biochemistry, 113 Neckers Building, Southern Illinois University, Carbondale, Illinois 62901, USA
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Li MJ, Lai CC, Liu YH, Peng SM, Chiu SH. Two guest complexation modes in a cyclotriveratrylene-based molecular container. Chem Commun (Camb) 2009:5814-6. [PMID: 19787106 DOI: 10.1039/b906075h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Ming-Jhe Li
- Department of Chemistry, National Taiwan University, Taipei, Taiwan, 10617, ROC
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Affiliation(s)
- Thierry Brotin
- Laboratoire de Chimie, CNRS, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon 07, France
| | - Jean-Pierre Dutasta
- Laboratoire de Chimie, CNRS, École Normale Supérieure de Lyon, 46 Allée d’Italie, F-69364 Lyon 07, France
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Brotin T, Cavagnat D, Buffeteau T. Conformational changes in cryptophane having C1-symmetry studied by vibrational circular dichroism. J Phys Chem A 2008; 112:8464-70. [PMID: 18710194 DOI: 10.1021/jp804450w] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vibrational circular dichroism (VCD) measurements and density functional theory (DFT) calculations were used to obtain the absolute configuration of a cryptophane molecule having C1-symmetry (labeled cryptophane-H). This molecule exhibits chiroptical properties different from those published for cryptophane-A having D3-symmetry [Brotin et al. J. Am. Chem. Soc. 2006, 128, 5533-5540]. In particular, we have shown that the conformation of the aliphatic linkers is very dependent on the solvent used and its ability to enter (CDCl3 solution) or not (C2D2Cl4 solution) in the cryptophane cavity. Calculations performed at the DFT (B3PW91/6-31G*) level establish, besides the absolute configuration, the preferential anti and gauche conformations of the aliphatic linkers of the chloroform@cryptophane-H complex and the empty cryptophane-H molecule, respectively. Polarimetric measurements performed in several solvents reflect also the change of conformation of the bridges upon guest encapsulation.
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Affiliation(s)
- Thierry Brotin
- Laboratoire de Chimie de l'ENS-LYON (UMR 5182-CNRS), Ecole Normale Supérieure de Lyon, 69364 Lyon 07, France
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Roy V, Brotin T, Dutasta JP, Charles MH, Delair T, Mallet F, Huber G, Desvaux H, Boulard Y, Berthault P. A cryptophane biosensor for the detection of specific nucleotide targets through xenon NMR spectroscopy. Chemphyschem 2008; 8:2082-5. [PMID: 17712828 DOI: 10.1002/cphc.200700384] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Vincent Roy
- Laboratoire de Chimie, CNRS, Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France
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Cavagnat D, Buffeteau T, Brotin T. Synthesis and Chiroptical Properties of Cryptophanes Having C1-Symmetry. J Org Chem 2007; 73:66-75. [DOI: 10.1021/jo701662w] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominique Cavagnat
- Institut des Sciences Moléculaires, UMR 5255 du CNRS, Université Bordeaux I, 351 Cours de la Libération, 33405 Talence, France, and Laboratoire de Chimie de l'ENS-LYON, UMR 5182 du CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France
| | - Thierry Buffeteau
- Institut des Sciences Moléculaires, UMR 5255 du CNRS, Université Bordeaux I, 351 Cours de la Libération, 33405 Talence, France, and Laboratoire de Chimie de l'ENS-LYON, UMR 5182 du CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France
| | - Thierry Brotin
- Institut des Sciences Moléculaires, UMR 5255 du CNRS, Université Bordeaux I, 351 Cours de la Libération, 33405 Talence, France, and Laboratoire de Chimie de l'ENS-LYON, UMR 5182 du CNRS, École Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France
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Brotin T, Cavagnat D, Dutasta JP, Buffeteau T. Vibrational circular dichroism study of optically pure cryptophane-A. J Am Chem Soc 2007; 128:5533-40. [PMID: 16620127 DOI: 10.1021/ja0603148] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vibrational circular dichroism (VCD) measurements and density functional theory (DFT) calculations were used to obtain the absolute configuration of optically pure cryptophane-A molecule. This large molecule (120 atoms) that possess a globular shape, but no chiral centers, exceeds the molecular size of published structures for which VCD has been used to determine the absolute configuration. VCD spectra recorded in CDCl(3) solution for the two resolved enantiomers are near mirror images, and very good agreement between the observed IR and VCD spectra and intensity calculations performed at the DFT (B3PW91/6-31G) level establish, besides the absolute configuration, the preferential anti conformation of the aliphatic linkers of the chloroform-cryptophane-A complex. Experiments performed in CD(2)Cl(2) and C(2)D(2)Cl(4) solutions show no significant modifications in the IR and VCD spectra, indicating that the conformation of the aliphatic linkers is similar for empty (C(2)D(2)Cl(4) solution) and encaged (CDCl(3) and CD(2)Cl(2) solutions) cryptophane-A molecules.
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Affiliation(s)
- Thierry Brotin
- Laboratoire de Chimie de l'ENS-LYON (UMR 5182-CNRS), Ecole Normale Supérieure de Lyon, 46 Allée d'Italie, 69364 Lyon 07, France
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Díaz Gómez E, Brotin T, Duddeck H. Enantiodifferentiation of polyethers by the dirhodium method. Part 2: Cyclotriveratrylenes and cryptophanes. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.09.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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Wei Q, Seward GK, Hill PA, Patton B, Dimitrov IE, Kuzma NN, Dmochowski IJ. Designing 129Xe NMR biosensors for matrix metalloproteinase detection. J Am Chem Soc 2007; 128:13274-83. [PMID: 17017809 DOI: 10.1021/ja0640501] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Xenon-129 biosensors offer an attractive alternative to conventional MRI contrast agents due to the chemical shift sensitivity and large nuclear magnetic signal of hyperpolarized (129)Xe. Here, we report the first enzyme-responsive (129)Xe NMR biosensor. This compound was synthesized in 13 steps by attaching the consensus peptide substrate for matrix metalloproteinase-7 (MMP-7), an enzyme that is upregulated in many cancers, to the xenon-binding organic cage, cryptophane-A. The final coupling step was achieved on solid support in 80-92% yield via a copper (I)-catalyzed [3+2] cycloaddition. In vitro enzymatic cleavage assays were monitored by HPLC and fluorescence spectroscopy. The biosensor was determined to be an excellent substrate for MMP-7 (K(M) = 43 microM, V(max) = 1.3 x 10(-)(8) M s(-1), k(cat)/K(M) = 7,200 M(-1) s(-1)). Enzymatic cleavage of the tryptophan-containing peptide led to a dramatic decrease in Trp fluorescence, lambda(max) = 358 nm. Stern-Volmer analysis gave an association constant of 9000 +/- 1,000 M(-1) at 298 K between the cage and Trp-containing hexapeptide under enzymatic assay conditions. Most promisingly, (129)Xe NMR spectroscopy distinguished between the intact and cleaved biosensors with a 0.5 ppm difference in chemical shift. This difference most likely reflected a change in the electrostatic environment of (129)Xe, caused by the cleavage of three positively charged residues from the C-terminus. This work provides guidelines for the design and application of new enzyme-responsive (129)Xe NMR biosensors.
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Affiliation(s)
- Qian Wei
- Department of Chemistry, University of Pennsylvania, USA
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41
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Affiliation(s)
- Dmitry M. Rudkevich
- Department of Chemistry & Biochemistry, The University of Texas at Arlington, Arlington, TX 76019‐0065, USA, Fax: +1‐817‐272‐3808
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42
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Ruiz EJ, Sears DN, Pines A, Jameson CJ. Diastereomeric Xe chemical shifts in tethered cryptophane cages. J Am Chem Soc 2007; 128:16980-8. [PMID: 17177449 DOI: 10.1021/ja066661z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cryptophane cages serve as host molecules to a Xe atom. Functionalization of cryptophane-A has permitted the development of Xe as a biosensor. Synthetic routes used to prepare cryptophanes result in racemic mixtures of the chiral cages. In the preparation of a tethered cryptophane-A cage for biosensor applications, some achiral and chiral substituents such as left-handed amino acids have been used. When the substituent is achiral, the NMR signal of the Xe atom in the functionalized cage in solution is a single isotropic peak, since the Xe shielding tensor components in the R and L cages differ by no more than the signs of the off-diagonal elements. Chiral substituents can split the cage-encapsulated Xe NMR signal into one or more sets of doublets, depending on the number of asymmetric centers in the substituent. We carry out quantum mechanical calculations of Xe nuclear magnetic shielding for the Xe atom at the same strategic position within an L cryptophane-A cage, under the influence of chiral potentials that represent r or l substituents outside the cage. Calculations of the Xe shielding response in the Lr and Ll diastereomeric pairs permit the prediction of the relative order of the Xe chemical shifts in solutions containing the Rl and Ll diastereomers. Where the substituent itself possesses two chiral centers, comparison of the calculated isotropic shielding responses in the Llr, Lrl, Rll, and Lrr systems, respectively, permits the prediction of the Xe spectrum of diastereomeric systems in solutions containing Llr, Rlr, Lll, and Rll systems. Assignment of the peaks observed in the experimental Xe NMR spectra is therefore possible, without having to undertake the difficult synthetic route that produces a single optically pure enantiomer.
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Affiliation(s)
- E Janette Ruiz
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
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43
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Segebarth N, Aïtjeddig L, Locci E, Bartik K, Luhmer M. Novel Method for the Measurement of Xenon Gas Solubility Using 129Xe NMR Spectroscopy. J Phys Chem A 2006; 110:10770-6. [PMID: 16970370 DOI: 10.1021/jp062679k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel method is presented for determining xenon partitioning between a gas phase and a liquid phase. An experimental setup which permits the simultaneous measurement of the 129Xe chemical shift in both the gas and the liquid phases, that is, under the same experimental conditions, has been designed. Xenon solubility is obtained via 129Xe chemical shift measurements in the gas phase. The method was validated against xenon solubility data from the literature; in general, the agreement is found to be within 3%. The solubility of xenon in three solvents for which data have not been previously reported (acetone, acetonitrile, and 1,1,2,2-tetrachloroethane) was determined using this novel method. 129Xe chemical shifts for dissolved xenon are also reported; it is found that xenon-xenon interactions may play a significant role in the liquid phase even at low equilibrium xenon pressures.
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Affiliation(s)
- Nicolas Segebarth
- Laboratoire de RMN Haute Résolution CP 160/08, Université Libre de Bruxelles, Belgium
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44
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Chagolla D, Mathias EV, Ba Y. Probing the interaction of solvents with the stationary phase of C18 high-performance liquid chromatographic column material by variable-temperature dependent 129Xe nuclear magnetic resonance spectroscopy. J Chromatogr A 2006; 1121:23-31. [PMID: 16635493 DOI: 10.1016/j.chroma.2006.03.117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 03/30/2006] [Accepted: 03/31/2006] [Indexed: 11/28/2022]
Abstract
VT (129)Xe NMR was applied to probe the interactions of solvents having different polarity indices with the stationary phase of a RP-C18 HPLC column material. It was observed that the highly polar ethylene glycol molecules do not mix with the alkyl chains of the RP-C18 stationary phase and the solvent is unable to enter the pores and the spaces between the particles. Three phases in this sample are defined as stationary/xenon phase, xenon gas phase (in the pores and the spaces between the particles) and ethylene glycol/xenon phase. In contrast to ethylene glycol, the nonpolar solvent cyclohexane was observed to be well mixed with the RP-C18 stationary phase. The capillary rise effect allows the solvent to enter the pores and the spaces between the particles. Two phases in this sample are defined as stationary/cyclohexane/xenon phase and cyclohexane/xenon phases. The properties of ethyl acetate are between those of ethylene glycol and cyclohexane. The (129)Xe NMR results show that the rational reversed phases should be conditioned from highly solvating to more polar solvents to remove the trapped air. The (129)Xe NMR results also show that pure stationary phase exists only when a highly polar solvent is used in reversed-phase chromatography. For a solvent with lower polarity, a stationary/solvent phase actually forms. This, together with the mobile phase, determines the selective factor for separating mixtures.
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Affiliation(s)
- Danny Chagolla
- Department of Chemistry and Biochemistry, California State University Los Angeles, 5151 State University Drive, Los Angeles, CA 90032, USA
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45
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Vukovic L, Jameson CJ, Sears DN. Intermolecular hyperfine tensor for Xe@O2. Density and temperature dependence of Xe chemical shifts in oxygen gas. Mol Phys 2006. [DOI: 10.1080/00268970500525614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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46
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Huber G, Brotin T, Dubois L, Desvaux H, Dutasta JP, Berthault P. Water Soluble Cryptophanes Showing Unprecedented Affinity for Xenon: Candidates as NMR-Based Biosensors. J Am Chem Soc 2006; 128:6239-46. [PMID: 16669694 DOI: 10.1021/ja060266r] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cryptophanes bearing OCH(2)COOH groups in place of the methoxy groups represent a new class of xenon-carrier molecules soluble in water at biological pH. By using (1)H and (129)Xe NMR (thermally- and laser-polarized dissolved gas), the structural and dynamical behaviors of these host molecules as well as their interaction with xenon are studied. They are shown to exist in aqueous solution under different conformations in very slow exchange. A saddle form present for one of these conformations could explain the (1)H NMR spectra. Whereas the cryptophanes in such a conformation are unable to complex xenon, unprecedented high binding constants are found for cryptophanes in the other canonical crown-crown conformation. These host molecules could therefore be valuable candidates for biosensing using (129)Xe MRI.
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Affiliation(s)
- Gaspard Huber
- Laboratoire Structure et Dynamique par Résonance Magnétique, DSM/DRECAM/Service de Chimie Moléculaire, URA CEA/CNRS 331, CEA/Saclay, F-91191 Gif sur Yvette, France
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47
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Chaffee KE, Marjanska M, Goodson BM. NMR studies of chloroform@cryptophane-A and chloroform@bis-cryptophane inclusion complexes oriented in thermotropic liquid crystals. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2006; 29:104-12. [PMID: 16213691 DOI: 10.1016/j.ssnmr.2005.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 08/09/2005] [Indexed: 05/04/2023]
Abstract
Oriented inclusion complexes of chloroform@cryptophane-A and chloroform@bis-cryptophane were prepared using a nematic thermotropic liquid crystal (ZLI 1132), and the alignment and magnetic resonance properties of these host-guest systems were studied via (13)C NMR of the labeled guests. Large (1)H-(13)C dipolar splittings for (13)CHCl(3) guests indicated significantly enhanced (approximately 2-fold) ordering for the trapped vs. free ligands under all conditions studied, with similar ordering observed for the two complexes-despite significant differences in size and motional freedom between the hosts. For each environment, variable-temperature studies permitted the sign and magnitude of the order parameter for chloroform's C-H bond to be independently determined from the (13)C chemical shift anisotropy (CSA) shifts (via the gradient method) and the restored (1)H-(13)C dipolar couplings. In both systems, the results are consistent with overall alignment of the complexes such that the cage principal axis lies roughly perpendicular to the LC director.
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Affiliation(s)
- Kathleen E Chaffee
- Department of Chemistry and Biochemistry, 113 Neckers Hall, Southern Illinois University, Carbondale, IL 62901, USA
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48
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Lowery TJ, Garcia S, Chavez L, Ruiz EJ, Wu T, Brotin T, Dutasta JP, King DS, Schultz PG, Pines A, Wemmer DE. Optimization of Xenon Biosensors for Detection of Protein Interactions. Chembiochem 2005; 7:65-73. [PMID: 16342304 DOI: 10.1002/cbic.200500327] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Hyperpolarized 129Xe NMR spectroscopy can detect the presence of specific low-concentration biomolecular analytes by means of a xenon biosensor that consists of a water-soluble, targeted cryptophane-A cage that encapsulates the xenon. In this work, we use the prototypical biotinylated xenon biosensor to determine the relationship between the molecular composition of the xenon biosensor and the characteristics of protein-bound resonances. The effects of diastereomer overlap, dipole-dipole coupling, chemical-shift anisotropy, xenon exchange, and biosensor conformational exchange on the protein-bound biosensor signal were assessed. It was found that an optimal protein-bound biosensor signal can be obtained by minimizing the number of biosensor diastereomers and using a flexible linker of appropriate length. Both the line width and sensitivity of chemical shift to protein binding of the xenon biosensor were found to be inversely proportional to linker length.
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Affiliation(s)
- Thomas J Lowery
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
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49
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Cuevas F, Ballester P, Pericàs MA. Structurally Simple, Modular Amino Alcohols for the Recognition of Carboxylic Acids. Application to the Development of a New Chiral Solvating Agent. Org Lett 2005; 7:5485-7. [PMID: 16288537 DOI: 10.1021/ol052490b] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[structure: see text] Two flexible receptors for carboxylic acids, based on 1-amino-3-fluoro-2-alcohol functional arrays and built on aminomethylpyridine platforms, are described. The C(2)-symmetric one [from 2,6-bis(aminomethyl)pyridine] has been shown to be an efficient CSA due to its ability to form geometrically different diastereomeric complexes enabling the discrimination between the enantiomers of a series of carboxylic acid in the (1)H NMR spectra.
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Affiliation(s)
- Félix Cuevas
- Institute of Chemical Research of Catalonia, Tarragona, Spain
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50
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Granwehr J, Urban JT, Trabesinger AH, Pines A. NMR detection using laser-polarized xenon as a dipolar sensor. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 176:125-39. [PMID: 16005649 DOI: 10.1016/j.jmr.2005.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 05/16/2005] [Accepted: 05/16/2005] [Indexed: 05/03/2023]
Abstract
Hyperpolarized (129)Xe can be used as a sensor to indirectly detect NMR spectra of heteronuclei that are neither covalently bound nor necessarily in direct contact with the Xe atoms, but coupled through long-range intermolecular dipole-dipole interactions. To reintroduce long-range dipolar couplings the sample symmetry has to be broken. This can be done either by using an asymmetric sample arrangement, or by breaking the symmetry of the spin magnetization with field gradient pulses. Experiments are performed where only a small fraction of the available (129)Xe magnetization is used for each point, so that a single batch of xenon suffices for the point-by-point acquisition of a heteronuclear NMR spectrum. Examples with (1)H as the analyte nucleus show that these methods have the potential to obtain spectra with a resolution that is high enough to determine homonuclear J couplings. The applicability of this technique with remote detection is discussed.
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Affiliation(s)
- J Granwehr
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Department of Chemistry, University of California, Berkeley, CA 94720, USA
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