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A Low-Spin CoII/Nitroxide Complex for Distance Measurements at Q-Band Frequencies. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pulse dipolar electron paramagnetic resonance spectroscopy (PDS) is continuously furthering the understanding of chemical and biological assemblies through distance measurements in the nanometer range. New paramagnets and pulse sequences can provide structural insights not accessible through other techniques. In the pursuit of alternative spin centers for PDS, we synthesized a low-spin CoII complex bearing a nitroxide (NO) moiety, where both the CoII and NO have an electron spin S of 1/2. We measured CoII-NO distances with the well-established double electron–electron resonance (DEER aka PELDOR) experiment, as well as with the five- and six-pulse relaxation-induced dipolar modulation enhancement (RIDME) spectroscopies at Q-band frequencies (34 GHz). We first identified challenges related to the stability of the complex in solution via DEER and X-ray crystallography and showed that even in cases where complex disproportionation is unavoidable, CoII-NO PDS measurements are feasible and give good signal-to-noise (SNR) ratios. Specifically, DEER and five-pulse RIDME exhibited an SNR of ~100, and while the six-pulse RIDME exhibited compromised SNR, it helped us minimize unwanted signals from the RIDME traces. Last, we demonstrated RIDME at a 10 μM sample concentration. Our results demonstrate paramagnetic CoII to be a feasible spin center in medium magnetic fields with opportunities for PDS studies involving CoII ions.
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Probing Small-Angle Molecular Motions with EPR Spectroscopy: Dynamical Transition and Molecular Packing in Disordered Solids. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8020019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Disordered molecular solids present a rather broad class of substances of different origin—amorphous polymers, materials for photonics and optoelectronics, amorphous pharmaceutics, simple molecular glass formers, and others. Frozen biological media in many respects also may be referred to this class. Theoretical description of dynamics and structure of disordered solids still does not exist, and only some phenomenological models can be developed to explain results of particular experiments. Among different experimental approaches, electron paramagnetic resonance (EPR) applied to spin probes and labels also can deliver useful information. EPR allows probing small-angle orientational molecular motions (molecular librations), which intrinsically are inherent to all molecular solids. EPR is employed in its conventional continuous wave (CW) and pulsed—electron spin echo (ESE)—versions. CW EPR spectra are sensitive to dynamical librations of molecules while ESE probes stochastic molecular librations. In this review, different manifestations of small-angle motions in EPR of spin probes and labels are discussed. It is shown that CW-EPR-detected dynamical librations provide information on dynamical transition in these media, similar to that explored with neutron scattering, and ESE-detected stochastic librations allow elucidating some features of nanoscale molecular packing. The possible EPR applications are analyzed for gel-phase lipid bilayers, for biological membranes interacting with proteins, peptides and cryoprotectants, for supercooled ionic liquids (ILs) and supercooled deep eutectic solvents (DESs), for globular proteins and intrinsically disordered proteins (IDPs), and for some other molecular solids.
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Golysheva E, Maslennikova N, Baranov DS, Dzuba S. Structural properties of supercooled deep eutectic solvents: choline chloride–thiourea compared to reline. Phys Chem Chem Phys 2022; 24:5974-5981. [DOI: 10.1039/d1cp05162h] [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
Deep eutectic solvents (DESs) are eutectic mixtures of hydrogen bond acceptors and hydrogen bond donors which melt at much lower temperatures than the individual components. DESs attract growing interest because...
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Ivanov MY, Surovtsev NV, Fedin MV. Ionic liquid glasses: properties and applications. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Ivanov MY, Prikhod’ko SA, Bakulina OD, Kiryutin AS, Adonin NY, Fedin MV. Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses. Molecules 2021; 26:5828. [PMID: 34641371 PMCID: PMC8510339 DOI: 10.3390/molecules26195828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 11/25/2022] Open
Abstract
Ionic liquid (IL) glasses have recently drawn much interest as unusual media with unique physicochemical properties. In particular, anomalous suppression of molecular mobility in imidazolium IL glasses vs. increasing temperature was evidenced by pulse Electron Paramagnetic Resonance (EPR) spectroscopy. Although such behavior has been proven to originate from dynamics of alkyl chains of IL cations, the role of electron spin relaxation induced by surrounding protons still remains unclear. In this work we synthesized two deuterated imidazolium-based ILs to reduce electron-nuclear couplings between radical probe and alkyl chains of IL, and investigated molecular mobility in these glasses. The obtained trends were found closely similar for deuterated and protonated analogs, thus excluding the relaxation-induced artifacts and reliably demonstrating structural grounds of the observed anomalies in heterogeneous IL glasses.
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Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Olga D. Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Alexey S. Kiryutin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia; (S.A.P.); (N.Y.A.)
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia; (O.D.B.); (A.S.K.)
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Ivanov MY, Bakulina OD, Alimov DV, Prikhod'ko SA, Veber SL, Pylaeva S, Adonin NY, Fedin MV. Inherent heterogeneities and nanostructural anomalies in organic glasses revealed by EPR. NANOSCALE ADVANCES 2021; 3:4973-4978. [PMID: 36132341 PMCID: PMC9416887 DOI: 10.1039/d1na00452b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 07/22/2021] [Indexed: 06/15/2023]
Abstract
Intriguing heterogeneities and nanostructural reorganizations of glassy ionic liquids (ILs) have recently been found using electron paramagnetic resonance (EPR) spectroscopy. Alkyl chains of IL cations play the key role in such phenomena and govern the anomalous temperature dependence of local density and molecular mobility. In this paper we evidence and study similar manifestations in a variety of common non-IL glasses, which also contain molecules with alkyl chains. A series of phthalates clearly demonstrates very similar behavior to imidazolium-based ILs with the same length of alkyl chain. Glasses of alkyl alcohols and alkyl benzenes show only some similarities to the corresponding ILs, mainly due to a lower glass transition temperature hindering the development of the anomaly. Therefore, we demonstrate the general nature and broad scope of nanoscale structural anomalies in organic glasses based on alkyl-chain compounds. The 'roadmap' for their occurrence is provided, which aids in understanding and future applications of these anomalous nanoheterogeneities.
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Affiliation(s)
- Mikhail Yu Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
| | - Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
- Novosibirsk State University Pirogova Street 2 630090 Novosibirsk Russia
| | - Dmitriy V Alimov
- Novosibirsk State University Pirogova Street 2 630090 Novosibirsk Russia
| | - Sergey A Prikhod'ko
- Boreskov Institute of Catalysis SB RAS Lavrentiev Avenue 5 630090 Novosibirsk Russia
| | - Sergey L Veber
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
| | - Svetlana Pylaeva
- Universität Paderborn Warburger Str. 100 33098 Paderborn Germany
| | - Nicolay Yu Adonin
- Boreskov Institute of Catalysis SB RAS Lavrentiev Avenue 5 630090 Novosibirsk Russia
| | - Matvey V Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a 630090 Novosibirsk Russia
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Ivanov MY, Poryvaev AS, Polyukhov DM, Prikhod'ko SA, Adonin NY, Fedin MV. Nanoconfinement effects on structural anomalies in imidazolium ionic liquids. NANOSCALE 2020; 12:23480-23487. [PMID: 33174581 DOI: 10.1039/d0nr06961b] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Imidazolium Ionic Liquids (ILs) have been found to exhibit unusual nanostructuring behavior below their glass transition temperatures (Tg), which is ascribed to rearrangements in nonpolar domains formed by segregated alkyl chains. However, the dimensions required for such highly cooperative bulk phenomena are still unknown. In this work, we for the first time, investigate the effect of nanoconfinement on structural anomalies in imidazolium ILs. For this purpose, a series of ILs were embedded into the cavities of metal-organic framework (MOF) ZIF-8 and investigated using spin probes and Electron Paramagnetic Resonance (EPR) spectroscopy. The unusual nanostructuring near Tg, previously known for bulk ILs, was also observed for such nanoconfined ILs, and the amplitude of the anomaly was found to be dependent on the structure of the IL, thus showing the effects of molecular packing inside the MOF cavity. The first observation of structural anomalies in nanoconfined ILs opens perspectives for designing smart materials exhibiting these phenomena, and engaging MOFs as platforms creates the basis for potential applications of such functionalities.
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Affiliation(s)
- Mikhail Yu Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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Bakulina OD, Ivanov MY, Prikhod'ko SA, Pylaeva S, Zaytseva IV, Surovtsev NV, Adonin NY, Fedin MV. Nanocage formation and structural anomalies in imidazolium ionic liquid glasses governed by alkyl chains of cations. NANOSCALE 2020; 12:19982-19991. [PMID: 32996529 DOI: 10.1039/d0nr06065h] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Intriguing nanostructuring anomalies have been recently observed in imidazolium ionic liquids (ILs) near their glass transition points, where local density around a nanocaged solute progressively grows up with temperature. Herewith, we for the first time demonstrate experimentally and theoretically, that these anomalies are governed by alkyl chains of cations and crucially depend on their length. Electron Paramagnetic Resonance (EPR) spectroscopy on a series of ILs [Cnmim]BF4 (n = 0-12) shows that only the chains with n = 3-10 favor anomaly. Moreover, remarkable even vs. odd n peculiarities were systematically observed. Finally, similar anomaly was for the first time observed for a non-IL glass of dibutyl phthalate, which structurally mimics cations of imidazolium ILs. Therefore, such anomalous density behavior in a glassy state nanocage goes far beyond ILs and proves to be a more general phenomenon, which can be structurally tuned and rationally adjusted for various potential applications in nanoscale materials.
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Affiliation(s)
- Olga D Bakulina
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia.
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Yang Y, Pan BB, Tan X, Yang F, Liu Y, Su XC, Goldfarb D. In-Cell Trityl-Trityl Distance Measurements on Proteins. J Phys Chem Lett 2020; 11:1141-1147. [PMID: 31951412 PMCID: PMC7307952 DOI: 10.1021/acs.jpclett.9b03208] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Double-electron electron resonance (DEER) can be used to track the structural dynamics of proteins in their native environment, the cell. This method provides the distance distribution between two spin labels attached at specific, well-defined positions in a protein. For the method to be viable under in-cell conditions, the spin label and its attachment to the protein should exhibit high chemical stability in the cell. Here we present low-temperature, trityl-trityl DEER distance measurements on two model proteins, PpiB (prolyl cis-trans isomerase from E. coli) and GB1 (immunoglobulin G-binding protein), doubly labeled with the trityl spin label, CT02MA. Both proteins gave in-cell distance distributions similar to those observed in vitro, with maxima at 4.5-5 nm, and the data were further compared with in-cell Gd(III)-Gd(III) DEER obtained for PpiB labeled with BrPSPy-DO3A-Gd(III) at the same positions. These results highlight the challenges of designing trityl tags suitable for in-cell distance determination at ambient temperatures on live cells.
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Affiliation(s)
- Yin Yang
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Bin-Bin Pan
- State
Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation
Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Xiaoli Tan
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin
Medical University, Tianjin 300070, China
| | - Feng Yang
- State
Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation
Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Yangping Liu
- Tianjin
Key Laboratory on Technologies Enabling Development of Clinical Therapeutics
and Diagnostics, School of Pharmacy, Tianjin
Medical University, Tianjin 300070, China
| | - Xun-Cheng Su
- State
Key Laboratory of Elemento-organic Chemistry, Collaborative Innovation
Center of Chemical Science and Engineering, Nankai University, Tianjin 300071, China
| | - Daniella Goldfarb
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 76100, Israel
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Golysheva EA, Samoilova RI, De Zotti M, Toniolo C, Formaggio F, Dzuba SA. Electron spin echo detection of stochastic molecular librations: Non-cooperative motions on solid surface. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 309:106621. [PMID: 31669794 DOI: 10.1016/j.jmr.2019.106621] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 10/12/2019] [Accepted: 10/12/2019] [Indexed: 06/10/2023]
Abstract
In frozen biological media and molecular glasses only restricted motions exist; because of the weakness and disorder of intermolecular bonds these motions may have stochastic nature. Electron spin echo (ESE) spectroscopy of spin-labeled molecules allows detecting their restricted stochastic rotations (stochastic molecular librations). As in molecular disordered media motions may be highly cooperative, it would be desirable to investigate their spectroscopic manifestation also in the systems where cooperative effects would be certainly ruled out. In this work, ESE of spin-labeled molecules adsorbed on inorganic SiO2 surface was investigated in a wide temperature range. The rate of motion-induced spin relaxation was found to become measurable above 130 K, increasing with temperature and attaining then a saturating behavior with a well-defined maximum near 250 K. For two types of molecules differing remarkably in their size and polarity (a small highly-polar nitroxide radical and a large spin-labeled peptide), quite similar results were obtained. This saturating behavior was quantitatively reproduced in simulations within a simple model of jump between two close orientations. Comparison with experiment allowed estimate that at 250 K the correlation time of the motion τc is of the order of several tens of nanoseconds and the angle α between two orientations is around 0.02 rad. As the found saturating behavior is a property of individual motions, for any other molecular system an excess of the spin relaxation rate above the maximum found here for adsorbed molecules may be ascribed to cooperative motions. Comparison with literature data on molecular systems of different origin has shown that effects of cooperativity indeed are present and, moreover, may be very essential.
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Affiliation(s)
- Elena A Golysheva
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Department of Physics, Novosibirsk State University, Novosibirsk 630090, Russian Federation
| | - Rimma I Samoilova
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
| | - Marta De Zotti
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy
| | - Claudio Toniolo
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy; Institute of Biomolecular Chemistry, Padova Unit, CNR, 35131 Padova, Italy
| | - Fernando Formaggio
- Department of Chemical Sciences, University of Padova, 35131 Padova, Italy; Institute of Biomolecular Chemistry, Padova Unit, CNR, 35131 Padova, Italy
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russian Federation; Department of Physics, Novosibirsk State University, Novosibirsk 630090, Russian Federation.
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Ivanov MY, Prikhod’ko SA, Adonin NY, Fedin MV. Structural Anomalies in Binary Mixtures of Ionic Liquid [Bmim]BF4 with Water Studied by EPR. J Phys Chem B 2019; 123:9956-9962. [DOI: 10.1021/acs.jpcb.9b08933] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Mikhail Yu. Ivanov
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
| | - Sergey A. Prikhod’ko
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Nicolay Yu. Adonin
- Boreskov Institute of Catalysis SB RAS, Lavrentiev Avenue 5, 630090 Novosibirsk, Russia
| | - Matvey V. Fedin
- International Tomography Center SB RAS, Institutskaya Street 3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova Street 2, 630090 Novosibirsk, Russia
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Ivanov MY, Fedin MV. Nanoscale heterogeneities in ionic liquids: insights from EPR of spin probes. MENDELEEV COMMUNICATIONS 2018. [DOI: 10.1016/j.mencom.2018.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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