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Facchinatto WM, Dos Santos DM, de Lacerda Bukzem A, Moraes TB, Habitzreuter F, de Azevedo ER, Colnago LA, Campana-Filho SP. Insight into morphological, physicochemical and spectroscopic properties of β-chitin nanocrystalline structures. Carbohydr Polym 2021; 273:118563. [PMID: 34560974 DOI: 10.1016/j.carbpol.2021.118563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/14/2021] [Accepted: 08/13/2021] [Indexed: 10/20/2022]
Abstract
We systematically investigated the effect of β-chitin (BCH) particle size on the preparation of nanocrystals/nanowhiskers (CWH) by acid hydrolysis. Regardless this variable, CWH aqueous suspension exhibited outstanding stability and the average degree of acetylation remained nearly constant after the acid treatment. In contrast, the morphology, dimensions, crystallinity, and molecular weight of CHW were significantly affect by the particle size. Although needle-like crystals have predominated, BCH particles sizes significantly affected the dimensions and asymmetry of CWH, as confirmed by the rheological and NMR relaxation (T2) behaviors. According to different SSNMR approaches, the acid hydrolysis meaningless affected the local chain conformation, while the spatial freedom of BCH intersheets, rated upon the mobility of methyl segments, was taken as evidence of higher permeability of acid into small particle sizes. Thus, this study demonstrated the importance of standardizing the surface/bulk proportions of β-chitin aiming to predict and control the CWH morphology and related properties.
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Affiliation(s)
- William Marcondes Facchinatto
- São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador sao-carlense 400, Zip Code 13560-590, PO Box 780, São Carlos, SP, Brazil.
| | - Danilo Martins Dos Santos
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, Zip Code 13560-970, PO Box 741, São Carlos, SP, Brazil
| | - Andrea de Lacerda Bukzem
- São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador sao-carlense 400, Zip Code 13560-590, PO Box 780, São Carlos, SP, Brazil
| | - Tiago Bueno Moraes
- Department of Chemistry, Institute of Exact Sciences, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Zip Code 31270-901, PO Box 702, Belo Horizonte, MG, Brazil
| | - Filipe Habitzreuter
- São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador sao-carlense 400, Zip Code 13560-590, PO Box 780, São Carlos, SP, Brazil
| | - Eduardo Ribeiro de Azevedo
- São Carlos Institute of Physics, University of São Paulo, Avenida Trabalhador São-carlense 400, Zip Code 13560-590, PO Box 369, São Carlos, SP, Brazil
| | - Luiz Alberto Colnago
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, Zip Code 13560-970, PO Box 741, São Carlos, SP, Brazil
| | - Sérgio Paulo Campana-Filho
- São Carlos Institute of Chemistry, University of São Paulo, Avenida Trabalhador sao-carlense 400, Zip Code 13560-590, PO Box 780, São Carlos, SP, Brazil
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Clotrimazole-loaded N-(2-hydroxy)-propyl-3-trimethylammonium, O-palmitoyl chitosan nanoparticles for topical treatment of vulvovaginal candidiasis. Acta Biomater 2021; 125:312-321. [PMID: 33639312 DOI: 10.1016/j.actbio.2021.02.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/10/2021] [Accepted: 02/18/2021] [Indexed: 01/15/2023]
Abstract
Vulvovaginal candidiasis (VVC) represents a considerable health burden for women. Despite the availability of a significant array of antifungal drugs and topical products, the management of the infection is not always effective, and new approaches are needed. Here, we explored cationic N-(2-hydroxy)-propyl-3-trimethylammonium, O-palmitoyl chitosan nanoparticles (NPs) as carriers of clotrimazole (CLT) for the topical treatment of VVC. CLT-NPs with approximately 280 nm in diameter were obtained by self-assembly in water and subsequent stabilization by ionic crosslinking with tripolyphosphate. The nanosystem featured pH-independent sustained drug release up to 24 h, which affected both in vitro anti-Candida activity and cytotoxicity. The CLT-loaded nanostructured platform yielded favorable selectivity index values for a panel of standard strains and clinical isolates of Candida spp. and female genital tract cell lines (HEC-1-A, Ca Ski and HeLa), as compared to the free drug. CLT-NPs also improved in vitro drug permeability across HEC-1-A and Ca Ski cell monolayers, thus suggesting that the nanocarrier may provide higher mucosal tissue levels of the active compound. Overall, data support that CLT-NPs may be a valuable asset for the topical treatment of VVC. STATEMENT OF SIGNIFICANCE: Topical azoles such as clotrimazole (CLT) are first line antifungal drugs for the management of vulvovaginal candidiasis (VVC), but their action may be limited by issues such as toxicity and poor capacity to penetrate the genital mucosa. Herein, we report on the ability of a new cationic N-(2‑hydroxy)-propyl-3-trimethylammonium, O-dipalmitoyl chitosan derivative (DPCat35) to yield tripolyphosphate-reinforced micelle-like nanostructures that are suitable carriers for CLT. In particular, these nanosystems were able to improve the in vitro selectivity index of the drug and to provide enhanced epithelial drug permeability when tested in cell monolayer models. These data support that CLT-loaded DPCat35 nanoparticles feature favorable properties for the development of new nanomedicines for the topical management of VVC.
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Facchinatto WM, Dos Santos Garcia RH, Dos Santos DM, Fiamingo A, Menezes Flores DW, Campana-Filho SP, de Azevedo ER, Colnago LA. Fast-forward approach of time-domain NMR relaxometry for solid-state chemistry of chitosan. Carbohydr Polym 2021; 256:117576. [PMID: 33483071 DOI: 10.1016/j.carbpol.2020.117576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 12/11/2020] [Accepted: 12/27/2020] [Indexed: 11/19/2022]
Abstract
Chitosans with different average degrees of acetylation and weight molecular weight were analyzed by time-domain NMR relaxometry using the recently proposed pulse sequence named Rhim and Kessemeier - Radiofrequency Optimized Solid-Echo (RK-ROSE) to acquire 1H NMR signal of solid-state materials. The NMR signal decay was composed of faster (tenths of μs) and longer components, where the mobile-part fraction exhibited an effective relaxation transverse time assigned to methyl hydrogens from N-acetyl-d-glucosamine (GlcNAc) units. The higher intrinsic mobility of methyl groups was confirmed via DIPSHIFT experiments by probing the 1H-13C dipolar interaction. RK-ROSE data were modeled by using Partial Least Square (PLS) multivariate regression, which showed a high coefficient of determination (R2 > 0.93) between RK-ROSE signal profile and average degrees of acetylation and crystallinity index, thus indicating that time-domain NMR consists in a promising tool for structural and morphological characterization of chitosan.
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Affiliation(s)
- William Marcondes Facchinatto
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil.
| | - Rodrigo Henrique Dos Santos Garcia
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Danilo Martins Dos Santos
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
| | - Anderson Fiamingo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Douglas William Menezes Flores
- Superior College of Agriculture "Luiz de Queiroz", University of Sao Paulo, Av. Padua Dias 11, CEP 13418-900, Caixa Postal 9, Piracicaba, SP, Brazil
| | - Sérgio Paulo Campana-Filho
- Sao Carlos Institute of Chemistry, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 780, Sao Carlos, SP, Brazil
| | - Eduardo Ribeiro de Azevedo
- Sao Carlos Institute of Physics, University of Sao Paulo, Av. Trabalhador sao-carlense 400, CEP 13566-590, Caixa Postal 369, Sao Carlos, SP, Brazil
| | - Luiz Alberto Colnago
- Brazilian Corporation for Agricultural Research, Embrapa Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, Caixa Postal 741, Sao Carlos, SP, Brazil
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Mitrikas G, Menenakou S. Electron spin relaxation properties of atomic hydrogen encapsulated in octavinyl POSS cages. Phys Chem Chem Phys 2020; 22:15751-15758. [PMID: 32627777 DOI: 10.1039/d0cp02479a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electron spin relaxation times of encapsulated atomic hydrogen in the vinyl derivative of silsesquioxane (R8Si8O12) cages (R = CH[double bond, length as m-dash]CH2) are studied in detail by pulse electron paramagnetic resonance (EPR) methods in the temperature range between 10 and 300 K. The temperature dependence of the spin-lattice relaxation time, T1, shows similar behaviour with previously studied derivatives that typically involve Raman and thermally activated processes. The room-temperature phase-memory time TM = 9 μs is comparable to those reported for different alkyl derivatives and exhibits a characteristic temperature dependence with a considerable reduction below 200 K as a result of dynamic effects like methyl group rotation. However, this reduction is modest for the vinyl derivative since the minimum observed TM = 5 μs is much longer than the value of 1 μs reported for methyl-containing derivatives like R = C2H5, C3H7 (n-propyl), or OSi(CH3)2H. This discrepancy is attributed to the different rotation dynamics of the vinyl group, as evidenced by the determined activation energy and rotation frequency.
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Affiliation(s)
- George Mitrikas
- Institute of Nanoscience and Nanotechnology, N.C.S.R. Demokritos, 15310 Athens, Greece.
| | - Stavroula Menenakou
- Institute of Nanoscience and Nanotechnology, N.C.S.R. Demokritos, 15310 Athens, Greece.
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Kubica-Misztal A, Rochowski P, Florek-Wojciechowska M, Kruk D. Dynamics of solid alanine by means of nuclear magnetic resonance relaxometry. J Chem Phys 2018; 146:164501. [PMID: 28456185 DOI: 10.1063/1.4980152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
1H nuclear magnetic resonance relaxometry was applied to investigate the dynamics of l-alanine in the solid phase (powder). The experimental studies were carried out in a very broad frequency range, covering four orders of magnitude-from 4 kHz to 40 MHz (referring to the 1H resonance frequency) in order to probe motional processes of much different time scales by a single experiment. To get access to the dynamics of different proton groups of alanine, the 1H spin-lattice relaxation measurements were performed for non-deuterated and partially deuterated alanine. The experiments were carried out in the temperature range of 293 K-370 K (non-deuterated alanine) and 318 K-370 K (partially deuterated alanine). As a result of a thorough theoretical analysis of the extensive set of experimental results, three motional processes occurring on different time scales are identified and quantitatively described. The slowest process occurs on a time scale of μs and it is attributed to the collective dynamics of a 3D hydrogen bond network of alanine, while the intermediate, attributed to the dynamics of the NH3 group, corresponds to the range of tenths of ns. The fast process describes the rotation of the CH3 group.
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Affiliation(s)
- A Kubica-Misztal
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348 Kraków, Poland
| | - P Rochowski
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland
| | - M Florek-Wojciechowska
- Department of Physics and Biophysics, University of Warmia and Mazury in Olsztyn, Oczapowskiego 4, 10-719 Olsztyn, Poland
| | - D Kruk
- Faculty of Mathematics and Computer Science, University of Warmia and Mazury in Olsztyn, Słoneczna 54, 10-710 Olsztyn, Poland
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6
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Pejov L, Petreska I, Kocarev L. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions. J Chem Phys 2015; 143:244704. [PMID: 26723699 DOI: 10.1063/1.4937411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.
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Affiliation(s)
- Ljupčo Pejov
- Department of Physical Chemistry, Institute of Chemistry, SS. Cyril and Methodius University, Arhimedova 5, P.O. Box 162, 1001 Skopje, Republic of Macedonia
| | - Irina Petreska
- Institute of Physics, Faculty of Natural Sciences and Mathematics, SS. Cyril and Methodius University, P.O. Box 162, 1001 Skopje, Republic of Macedonia
| | - Ljupčo Kocarev
- Macedonian Academy of Sciences and Arts, Krste Misirkov 2, P.O. Box 428, 1000 Skopje, Republic of Macedonia
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Zhang B, Horsewill AJ. Methyl tunnelling sidebands in the low-field NMR spectrum of 3-pentanone: Driving A-E transitions using rf irradiation. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 258:33-39. [PMID: 26183303 DOI: 10.1016/j.jmr.2015.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/18/2015] [Accepted: 06/20/2015] [Indexed: 06/04/2023]
Abstract
Using magnetic field-cycling at cryogenic temperatures, low-field dipole-dipole driven NMR spectra have been recorded on 3-pentanone (CH3CH2C(O)CH2CH3). The spectra are characterised by tunnelling sidebands arising from the quantum dynamics of the methyl (CH3) rotors. From the sideband frequencies, the CH3 tunnelling frequency is determined to be νt=3.05±0.01MHz. The tunnelling sidebands are characterised by A-E transitions in nuclear spin-symmetry, involving simultaneous changes in tunnelling and nuclear spin states. To gain further insight, a theoretical analysis of the spin Hamiltonian matrix has been used to calculate the sideband transition probabilities. These are subsequently used in a thermodynamic model to simulate the low-field NMR spectrum which is compared with experiment. The level-crossings encountered as part of the magnetic field-cycling NMR sequence are found to play an essential role in determining the tunnelling sideband intensities.
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Affiliation(s)
- Bo Zhang
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Anthony J Horsewill
- School of Physics & Astronomy, University of Nottingham, Nottingham NG7 2RD, UK.
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Petreska I, Pejov L, Kocarev L. Exploring the possibilities to control the molecular switching properties and dynamics: A field-switchable rotor-stator molecular system. J Chem Phys 2011; 134:014708. [PMID: 21219021 DOI: 10.1063/1.3519638] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A bistable, dipolar stator-rotor molecular system-candidate for molecular electronics is investigated. We demonstrate that it is possible to control the intramolecular torsional states and dynamics in this system by applying an appropriate additional electric field (instead of biasing one), achieving fine tuning and modulation of the relevant properties. The electric field effects on the quantities responsible for torsional dynamics (potential energy surface, potential barrier height, quantum and classical transition probabilities, correlation time, HOMO-LUMO gap) are studied from first principles. Our results indicate that it is possible to artificially stabilize the metastable conformational state of the studied molecule. The importance of this is evident, as the current-voltage characteristics of the metastable state are clearly distinguishable from the current-voltage characteristics of the two stable states. We report for the first time exact calculations related to the possibilities to control the thermally induced stochastic switching, and reduce the noise in a practical application. Thus, we believe that the molecule studied in this paper could operate as a field-switchable molecular device under real conditions.
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Affiliation(s)
- Irina Petreska
- Institute of Physics, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, P.O. Box 162, 1000 Skopje, Republic of Macedonia.
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Sun C, Horsewill AJ. A field-cycling NMR investigation of resonant spin-lattice relaxation features arising from tunnelling methyl groups. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 35:139-146. [PMID: 18951766 DOI: 10.1016/j.ssnmr.2008.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 08/27/2008] [Accepted: 08/28/2008] [Indexed: 05/27/2023]
Abstract
(1)H nuclear spin-lattice relaxation has been investigated in sodium acetate trihydrate and sorbic acid using field-cycling NMR in the solid state. The relaxation is dominated by the reorientation of the methyl groups. Resonant features arising from coherent tunnelling are observed in both the magnetic field dependence of the spin lattice relaxation rate, T(1)(-1)(B(z)) and in the inverse temperature dependence, T(1)(-1)(1/T). The two systems have different barrier heights and tunnelling frequencies, providing different perspectives on the tunnel resonance phenomena. The magnetic field dependence enables different spectral density components to be separately investigated and in the carboxylic acid, sorbic acid, concerted proton transfer in the hydrogen bonds is also identified at low field and low temperature. The methyl hindering barriers and the correlation times characterising the reorientational dynamics has been accurately determined in both materials.
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Affiliation(s)
- C Sun
- School of Physics & Astronomy, University of Nottingham, Nottingham, UK
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10
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Pejov L, Rosa ML, Kocarev L. Dynamics of the central phenylene ring torsional motion in halogenated phenylene ethynylene oligomers. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.05.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Latanowicz L, Medycki W, Jakubas R. The Effect of Low-Temperature Dynamics of the Dimethylammonium Group in [(CH3)2NH2]3Sb2Cl9 on Proton Spin−Lattice Relaxation and Narrowing of the Proton NMR Line. J Phys Chem A 2005; 109:3097-104. [PMID: 16833635 DOI: 10.1021/jp045080y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper reports the temperature dependence of the relaxation time T1 (55.2 and 90 MHz) and the second moment of the NMR line for protons in a polycrystalline sample of [NH2(CH3)2]3Sb2Cl9 (DMACA). The fundamental aspects of molecular dynamics from quantum tunneling at low temperatures to thermally activated reorientation at elevated temperatures have been studied. The experimentally observed spin-lattice relaxation rate is a consequence of dipolar interactions between the spin pairs inside the methyl group (1/T(1AE) contribution) as well as the spins belonging to neighboring methyl groups and pairs, methyl spin-outer methyl spin (1/T(1EE) contribution). These contributions are considered separately. Two methyl groups in the dimethylammonium (DMA) cations are dynamically inequivalent. The values of the tunnel splitting of separate methyl groups are obtained from the T1 (55.2 MHz) experiment. The tunneling dynamics taking place below the characteristic temperatures 74 and 42 K for separate methyl groups are discussed in terms of the Schrödinger equation. These temperatures point to the one at which thermal energy C(p)T and potential barrier take the same value. It is established that the second moment of the proton NMR line below 74 K up to liquid helium temperature is much lower than the rigid lattice value, which is due to a tunneling stochastic process of the methyl groups.
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Affiliation(s)
- L Latanowicz
- Department of Biophysics, Institute of Biotechnology and Environmental Sciences, University of Zielona Gora, Monte Cassino 21 B, 65-561 Zielona Gora, Poland.
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Latanowicz L. Proton Spin−Lattice Relaxation of Tunneling Methyl Groups: Calculation of the Time Dependent Correlation Functions. J Phys Chem A 2004. [DOI: 10.1021/jp047668a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- L. Latanowicz
- Institute of Biotechnology and Environmental Sciences, University of Zielona Góra, Monte Cassino 21 B, 65-651 Zielona Góra, Poland
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13
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ZECEVIC ANA, EATON GARETHR, EATON SANDRAS, LINDGREN MIKAEL. Dephasing of electron spin echoes for nitroxyl radicals in glassy solvents by non-methyl and methyl protons. Mol Phys 1998. [DOI: 10.1080/00268979809483256] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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Neumann M, Johnson M, Aibout A, Horsewill A. Measured and calculated rotational tunnelling dynamics in methyl acetate. Chem Phys 1998. [DOI: 10.1016/s0301-0104(98)00039-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Prager M, Heidemann A. Rotational Tunneling and Neutron Spectroscopy: A Compilation. Chem Rev 1997; 97:2933-2966. [PMID: 11851482 DOI: 10.1021/cr9500848] [Citation(s) in RCA: 209] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Prager
- Institut Laue-Langevin, B.P. 156, F-38042 Grenoble, France
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Scheurer C, Wiedenbruch R, Meyer R, Ernst RR, Heinekey DM. Quantum mechanical exchange in a transition metal hydride complex: NMR data for [cp(PPh3)IrH3]+ fitted by a two-dimensional model. J Chem Phys 1997. [DOI: 10.1063/1.474112] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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