Log in

Relevant bibliographies by topics / Molecular motion of methyl group / Journal articles

To see the other types of publications on this topic, follow the link: Molecular motion of methyl group.

Journal articles on the topic 'Molecular motion of methyl group'

Author: Grafiati

Published: 4 June 2021

Last updated: 15 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Molecular motion of methyl group.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Gascooke, Jason R., and Warren D. Lawrance. "The Case for Methyl Group Precession Accompanying Torsional Motion." Australian Journal of Chemistry 73, no. 8 (2020): 775. http://dx.doi.org/10.1071/ch19469.

Full text

Abstract:

For molecules containing a methyl group, high precision fits of rotational line data (microwave spectra) that encompass several torsional states require considerably more constants than are required in comparable rigid molecules. Many of these additional terms are ‘torsion-rotation interaction’ terms, but their precise physical meaning is unclear. In this paper, we explore the physical origins of many of these additional terms in the case where the methyl group is attached to a planar frame. We show that torsion-vibration coupling, which has been observed in toluene and several substituted tol

APA, Harvard, Vancouver, ISO, and other styles

2

Nishikiori, Shinichi, Christopher I. Ratcliffe, and John A. Ripmeester. "Molecular motion of guests trapped in N-methyl-1,3-diaminopropanecadmium(II) tetracyanonickelate(II) host lattices." Canadian Journal of Chemistry 71, no. 11 (1993): 1810–15. http://dx.doi.org/10.1139/v93-225.

Full text

Abstract:

The molecular motion of guest molecules in Cd(mtn)Ni(CN)4•0.5G clathrates (mtn = N-methyl-1,3-diaminopropane, G = toluene, nitrobenzene, dichloromethane, and chloroform) were studied by using CP/MAS 13C and 2H NMR techniques. At room temperature, application of 13C CP/MAS NMR with dipolar dephasing showed the presence of large amplitude molecular motion in all cases. Temperature dependent 2H NMR spectra for the toluene-d8 clathrate shows that the methyl group rotated at all temperatures down to 77 K. Also, a 2-site in-plane reorientation process of the entire molecule is activated above 180 K,

APA, Harvard, Vancouver, ISO, and other styles

3

Szafrańska, Barbara, and Zdzisław Pająk. "Molecular Motion in Solid Tetraethyl-and Tetrabutylammonium Perchlorates." Zeitschrift für Naturforschung A 49, no. 3 (1994): 465–68. http://dx.doi.org/10.1515/zna-1994-0303.

Full text

Abstract:

Abstract The proton NMR second moment and spin-lattice relaxation time for polycrystalline tetraethyl-and tetrabutylammonium perchlorates have been measured over a wide range of temperatures. Solid-solid phase transitions related to the onset of cation tumbling were found for both compounds and confirmed by DSC. In the low temperature phases methyl-group reorientation was evidenced. For tetrabutylammonium cation a dynamic nonequivalence of one methyl group is found. The geared motion of the alkyl chains related with the onset of successive CH2-group reorientations is suggested.

APA, Harvard, Vancouver, ISO, and other styles

4

Lewicki, S., B. Szafranska, and Z. Pajak. "Molecular Motion in Solid Tetrapropylammonium Bromide and Iodide." Zeitschrift für Naturforschung A 47, no. 11 (1992): 1115–18. http://dx.doi.org/10.1515/zna-1992-1103.

Full text

Abstract:

Abstract The proton NMR second moment and spin-lattice relaxation time for tetrapropylammonium bromide and iodide have been measured over a wide temperature range. A solid-solid phase transition related to the onset of cation tumbling was found for both salts and confirmed by DTA. In the low temperature phases methyl group reorientation was evidenced. For iodide a dynamic nonequivalence of the methyl groups and the onset of ethyl groups motion was also discovered

APA, Harvard, Vancouver, ISO, and other styles

5

Szafrańska, Barbara, and Zdzisław Pająk. "Molecular Motion in Solid Tetrabutylammonium Iodide." Zeitschrift für Naturforschung A 42, no. 3 (1987): 253–57. http://dx.doi.org/10.1515/zna-1987-0307.

Full text

Abstract:

The temperature dependence of the 1H second moment and the T1 and T1ϱ spin-lattice relaxation times obtained for polycrystalline tetrabutylammonium iodide are interpreted in terms of the C3 methyl group reorientation appearing together with cationic tumbling for which the activation parameters have been determined. IR spectra point to the existence of weak C - H . . . I hydrogen bonds. A structural phase transition evidenced at about 386 K is found to be related to the onset of cationic self-diffusion.

APA, Harvard, Vancouver, ISO, and other styles

6

Garbutt, Jennifer R., Gillian R. Goward, Christopher W. Kirby, and William P. Power. "Solid-state 2H NMR study of methyl-d3-cobalamin." Biochemistry and Cell Biology 76, no. 2-3 (1998): 423–28. http://dx.doi.org/10.1139/o98-057.

Full text

Abstract:

A solid-state 2H NMR study of methyl-d3-cobalamin has been performed as a function of temperature to provide information concerning the character and energetics of the motion performed by this unique bioorganometallic methyl group. Analysis of the 2H NMR line shape indicates that the methyl group undergoes rapid three-fold rotation, and that the Co-C-2H angle lies between 105.9 and 109.5°. Determination of the spin-lattice relaxation times T1 shows that the relaxation is anisotropic, consistent with a "jumping" motion of the methyl group rather than rotational diffusion. This also provides the

APA, Harvard, Vancouver, ISO, and other styles

7

Wachner, Andrew M., Kenneth R. Jeffrey, and Glenn H. Penner. "A 2D deuterium NMR study of molecular reorientation in (CH3)3E+X- onium salts." Canadian Journal of Chemistry 78, no. 1 (2000): 46–50. http://dx.doi.org/10.1139/v99-226.

Full text

Abstract:

Two dimensional deuterium NMR measurements are reported for three different onium salts (CH3)3SeNO3-d3, (CH3)3TeI-d3, and (CH3)3SI-d9. In these molecular solids with the general structure (CH3)3E+X-, three methyl groups are attached to the E atom. There is the possibility of reorientation of the methyls about their C3 axes and reorientation of the whole tri-methyl group about the C'3 axis. From an analysis of the 2D NMR exchange spectra the angle between the E-C bonds and the rotation axis for trimethyl reorientation were determined. Exchange rates and spin lattice relaxation times are given f

APA, Harvard, Vancouver, ISO, and other styles

8

Szafrańska, Barbara, and Zdzisław Pająk. "Molecular Motion in Solid Tetraethyl -and Tetrapropylammonium Tetrafluoroborates." Zeitschrift für Naturforschung A 50, no. 6 (1995): 584–88. http://dx.doi.org/10.1515/zna-1995-0610.

Full text

Abstract:

Abstract Proton and fluorine NMR second moments and spin-lattice relaxation times for polycrystalline tetraethyl-and tetrapropylammonium tetrafluoroborates have been measured over a wide range of temperatures. Solid-solid phase transitions were found for both compounds and confirmed by DSC. Methyl group C3 reorientation followed by more complex cation motions was evidenced in the low temperature phases. Overall cation reorientation characterises the high temperature phases of both compounds. Isotropic anion reorientation was found in both salts in both phases.

APA, Harvard, Vancouver, ISO, and other styles

9

Szafrańska, B., H. Małuszyńska, and Z. Pająk. "Molecular Motion and Crystal Structure of Solid Tetrapentylammonium Iodide." Zeitschrift für Naturforschung A 55, no. 8 (2000): 706–10. http://dx.doi.org/10.1515/zna-2000-0806.

Full text

Abstract:

Abstract The proton NMR spectra and spin-lattice relaxation times of tetrapentylammonium iodide have been measured between 100 K and the melting point. The room temperature crystal structure has been determined by X-ray diffraction as orthorhombic, space group Ccca, Z = 4 with a = 10.811(2), b = 22.771(5) and c = 9.500(2) Å with fully ordered tetrapentylammonium cations. The existence of a solid-solid phase transition at 400 K has been confirmed by DTA. The onset of C 3 methyl group reorientations characterized by Arrhenius activation parameters has been evidenced. The intracation conformation

APA, Harvard, Vancouver, ISO, and other styles

10

Burbach, Günter, Norbert Weiden, and Alarich Weiss. "Molecular Motions in Solid [Sb(CH3)4]PF6. A Combined 11H,9F Nuclear Magnetic Resonance and Quasielastic Neutron Scattering Study." Zeitschrift für Naturforschung A 47, no. 5 (1992): 689–701. http://dx.doi.org/10.1515/zna-1992-0510.

Full text

Abstract:

Abstract The molecular dynamics of tetramethylstibonium hexafluorophosphate, [Sb(CH3)4]PF6, is investigated over a broad temperature range. NMR spin lattice relaxation times T1 and the NMR second moments of the 1H and 19F nuclei were determined in the range 8.6 ≦ T/K ≦ 332.3 for polycrystalline [Sb(CH3)4]PF6. The complex cation undergoes isotropic tumbling for T > 260 K and thermally activated methyl group rotation in the temperature range T < 196 K. The activation energies for the transition from methyl group rotation to cation reorientation, as derived from NMR wideline (18.1 kJ/mol) a

APA, Harvard, Vancouver, ISO, and other styles

11

Yang, Zhi-Yu, Chin-Wen Chen, and Syang-Peng Rwei. "Influence of asymmetric substituent group 2-methyl-1,3-propanediol on bio-based poly(propylene furandicarboxylate) copolyesters." Soft Matter 16, no. 2 (2020): 402–10. http://dx.doi.org/10.1039/c9sm02081k.

Full text

Abstract:

The effect of the pendant methyl group weakens gas barrier properties owing to small-scale molecular motion and an increase of free volume. These novel copolyesters have great potential for packing-related applications.

APA, Harvard, Vancouver, ISO, and other styles

12

Karthikeyan, S., P. Narayanan, K. Sethusankar, Anthonisamy Devaraj, and Manickam Bakthadoss. "Methyl 3′-(2,5-dimethylbenzyl)-1′-methyl-2-oxo-4′-phenylspiro[indoline-3,2′-pyrrolidine]-3′-carboxylate chloroform monosolvate." Acta Crystallographica Section E Structure Reports Online 70, no. 3 (2014): o377—o378. http://dx.doi.org/10.1107/s1600536814004073.

Full text

Abstract:

In the title solvate, C29H30N2O3·CHCl3, the dihedral angle between the indole ring system (r.m.s. deviation = 0.050 Å) and the 4-methylpyrrolidine ring is 88.88 (8)°. The latter ring adopts an envelope conformation with the N atom as the flap. Its mean plane makes dihedral angles of 86.94 (11) and 42.08 (9)° with the phenyl and dimethylbenzene rings, respectively. The molecular conformation is stabilized by intramolecular C—H...O hydrogen bonds, which generateS(6) andS(9) ring motifs. The chloroform solvent molecule is linked to the organic molecule by a C—H...O hydrogen bond involving the car

APA, Harvard, Vancouver, ISO, and other styles

13

Nagaoka, Naomi, Takahiro Ueda, and Nobuo Nakamura. "Dynamics of some n-Alkanes Adsorbed in the Micropore of (±)-[Co(en)3]Cl3 as Studied by 2H NMR." Zeitschrift für Naturforschung A 57, no. 6-7 (2002): 435–40. http://dx.doi.org/10.1515/zna-2002-6-726.

Full text

Abstract:

The dynamic behavior of n-hexane-d14 and n-decane-d22, adsorbed in the micropore of [Co(en)3]Cl3 crystal was studied by 2H NMR at 144 - 345 K. The quadrupole coupling constants (QCC) are 160 kHz for the methylene group and 60 kHz for methyl group below 144 K for hexane and below 178 K for decane, suggesting that the molecular reorientation about the molecular long axis is frozen below these temperatures. The QCC of CD2 group in hexane decreases from 160 kHz to 80 kHz on heating up to 170 K. Similar reduction of QCC of CD2 observed above 280 K for decane. Assuming the three-site jump model of t

APA, Harvard, Vancouver, ISO, and other styles

14

Khairy, Yasmin, Fernando Alvarez, Arantxa Arbe, and Juan Colmenero. "Disentangling Self-Atomic Motions in Polyisobutylene by Molecular Dynamics Simulations." Polymers 13, no. 4 (2021): 670. http://dx.doi.org/10.3390/polym13040670.

Full text

Abstract:

We present fully atomistic molecular dynamics simulations on polyisobutylene (PIB) in a wide temperature range above the glass transition. The cell is validated by direct comparison of magnitudes computed from the simulation and measured by neutron scattering on protonated samples reported in previous works. Once the reliability of the simulation is assured, we exploit the information in the atomic trajectories to characterize the dynamics of the different kinds of atoms in PIB. All of them, including main-chain carbons, show a crossover from Gaussian to non-Gaussian behavior in the intermedia

APA, Harvard, Vancouver, ISO, and other styles

15

Schaefer, Ted, Kerry J. Cox, Cherrie L. Morier, Christian Beaulieu, Rudy Sebastian, and Glenn H. Penner. "Motion about the bond in benzyl OR (R = CH3, CH2CH3, CH(CH3)2, C(CH3)3). Solvent and substituent dependence." Canadian Journal of Chemistry 68, no. 9 (1990): 1553–58. http://dx.doi.org/10.1139/v90-240.

Full text

Abstract:

The 1H nuclear magnetic resonance spectral parameters of benzyl alkyl ethers (CH3, CH2CH3, CH(CH3)2, and C(CH3)3) in CS2 and acetone-d6 solutions are obtained, as are those for the 3,5-dichloro derivatives (CH3, CH2CH3, and CH(CH3)3) in acetone-d6 solution. The long-range coupling constants between the methylene and para ring protons show that the apparent twofold barrier to rotation about the [Formula: see text] bond is solvent and ring-substituent dependent. The apparent twofold barrier ranges from a vanishing value for benzyl methyl ether in CS2 solution to as much as 4.6 kJ/mol for 3,5-dic

APA, Harvard, Vancouver, ISO, and other styles

16

Mellor, Yurchenko, Mant, and Jensen. "Transformation Properties under the Operations of the Molecular Symmetry Groups G36 and G36(EM) of Ethane H3CCH3." Symmetry 11, no. 7 (2019): 862. http://dx.doi.org/10.3390/sym11070862.

Full text

Abstract:

In the present work, we report a detailed description of the symmetry propertiesof the eight-atomic molecule ethane, with the aim of facilitating the variational calculations ofrotation-vibration spectra of ethane and related molecules. Ethane consists of two methyl groupsCH3 where the internal rotation (torsion) of one CH3 group relative to the other is of large amplitudeand involves tunnelling between multiple minima of the potential energy function. The molecularsymmetry group of ethane is the 36-element group G36, but the construction of symmetrised basisfunctions is most conveniently done

APA, Harvard, Vancouver, ISO, and other styles

17

Venu, K., and V. S. S. Sastry. "Proton Spin Lattice Relaxation in the Dimethylammonium Group." Zeitschrift für Naturforschung A 48, no. 5-6 (1993): 713–19. http://dx.doi.org/10.1515/zna-1993-5-624.

Full text

Abstract:

Abstract A model for the spin lattice relaxation time of the protons of dimethylammonium in the Redfield limit and common spin temperature approximation is developed. The three fold reorientations of the methyl groups, the rotation of the whole molecular group around its two fold symmetric axis and possible correlations among these motions are considered. The effect of these processes on the dipolar interactions among the protons within the same molecular group is taken into account. The resulting relaxation rate is powder averaged and used to explain the experimental data in literature on [NH

APA, Harvard, Vancouver, ISO, and other styles

18

Chihara, Yukiko N., Nobuo Nakamura, and Hideaki Chihara. "Molecular motion in the crystalline donor–acceptor complex trimethylamine–trifluoroborane as studied by proton and fluorine magnetic resonance." Canadian Journal of Chemistry 66, no. 8 (1988): 1848–52. http://dx.doi.org/10.1139/v88-298.

Full text

Abstract:

The proton and fluorine second moments and the spin-lattice relaxation times T1 (at 25.75 MHz) were measured in the solid complex trimethylamine–trifluoroborane from 53 to 300 K. There is a cross-relaxation effect between 1H and 19F below 120 K. Their T1 minima near 140 K led to activation energies of 10.6 and 11.1 kJ mol−1 for the reorientation of the methyl and the trifluoride groups, respectively. An additional minimum observed in the T1 of protons at about 240 K was attributed to the reorientation of the trimethylamine group about the N—B bond with an activation energy of 25.0 kJ mol−1. A

APA, Harvard, Vancouver, ISO, and other styles

19

Sgarabotto, Paolo, Mario Braghetti, Rosario Sergio Cataliotti, et al. "Phonon spectra of ortho -dinitrotetramethylbenzene crystals." Canadian Journal of Chemistry 65, no. 9 (1987): 2122–25. http://dx.doi.org/10.1139/v87-353.

Full text

Abstract:

We have studied the vibrational spectra and thermal behaviour of ortho-dinitrotetramethylbenzene (o-DNTMB) to learn more about its molecular and lattice dynamics. The molecule undergoes two solid–solid phase transitions, close to the melting point, which could be explained by the relaxation of forces hindering the methyl-group and nitro-group free rotations. We have deduced the nature of the solid state vibrational motions, particularly those of lattice phonons, using group theory.

APA, Harvard, Vancouver, ISO, and other styles

20

Zhang, Da, Shi-Qi Dou, and Alarich Weiss. "Molecular Motions in (CH3)3XCl, X = Sn and Pb. NMR Investigations and Crystal Structure Study of (CH3)3PbCl and CH3SnBr3." Zeitschrift für Naturforschung A 46, no. 4 (1991): 337–43. http://dx.doi.org/10.1515/zna-1991-0407.

Full text

Abstract:

Abstract The molecular motion in (CH3)3XCl, X = Sn and Pb has been investigated by measurement of the second moment M2(1H) as function of temperature in the range 95 < T,/K<345. The methyl groups in both compounds rotate freely over the whole temperature range studied. In (CH3)3SnCl the C'3-rotation of (CH3)3Sn-group about the Sn CI axis sets in above 273 K. To explain the NMR and INS results, the crystal structures of (CH3)3PbCl and CH3SnBr3 were determined by single X-ray diffraction. (CH3)3PbCl crystallizes in a monoclinic space group C32-C2, a = 1276.7(3) pm, b = 982.3(3) pm, c = 547

APA, Harvard, Vancouver, ISO, and other styles

21

Ishihara, Hideta, Keizo Horiuchi, and Yoshihiro Furukawa. "1H NMR Studies on the Cation Motions in Crystalline Cadmium Bromide Complexes [C(NH2)3]Cd2Br5, [(CH3)3NH]3Cd2Br7, and [i-C3H7NH3]CdBr3." Zeitschrift für Naturforschung B 65, no. 4 (2010): 499–502. http://dx.doi.org/10.1515/znb-2010-0410.

Full text

Abstract:

1H NMR T1 measurements of crystalline [C(NH2)3]Cd2Br5 showed a single minimum due to the C3 reorientation of the planar [C(NH2)3]+ ion with an activation energy (Ea) of 35.8 kJ mol−1. In [(CH3)3NH]3Cd2Br7 crystals, two T1 minima appeared which are assigned to the C3 reorientation of methyl groups in the [(CH3)3NH]+ cation with Ea = 13.0 kJ mol−1 and to the C3 reorientation of a whole cation around the molecular C3 axis with Ea = 28.9 kJ mol−1. In [i-C3H7NH3]CdBr3 crystals, a very broad T1 minimum appeared near 160 K which is assigned to the C3 reorientations of two methyl groups with Ea = 11.3

APA, Harvard, Vancouver, ISO, and other styles

22

Andreis, Mladen, Juwhan Liu, and Jack L. Koenig. "Solid-State Carbon-13 NMR Studies of Vulcanized Elastomers. VI. Relaxation in Sulfur-Vulcanized Natural Rubber." Rubber Chemistry and Technology 62, no. 1 (1989): 82–97. http://dx.doi.org/10.5254/1.3536237.

Full text

Abstract:

Abstract Molecular motions in sulfur-vulcanized NR are investigated by solid state 13C NMR relaxation techniques. Since the high-resolution spectra of crosslinked samples exhibit overlapping in the aliphatic region, a combined application of variable temperature spin-lattice relaxation measurements and the computer simulation of the overlapped spectral region is used in order to detect resonance signals. Motional restrictions introduced by crosslinks are investigated from the temperature dependence of nT1 relaxation times for individual carbons. The V-curves for all polyisoprene signals and fo

APA, Harvard, Vancouver, ISO, and other styles

23

Fonseca, Alexandra S., and Adailton J. Bortoluzzi. "Crystal structure of 3-[({2-[bis(2-hydroxybenzyl)amino]ethyl}(2-hydroxybenzyl)amino)methyl]-2-hydroxy-5-methylbenzaldehyde." Acta Crystallographica Section E Structure Reports Online 70, no. 12 (2014): 562–65. http://dx.doi.org/10.1107/s1600536814024465.

Full text

Abstract:

The non-symmetric title molecule, C32H34N2O5, is based on a tetrasubstituted ethylenediamine backbone. The molecular structure consists of three hydroxybenzyl groups and one 2-hydroxy-5-methylbenzaldehyde group bonded to the N atoms of the diamine unit. The ethylenediamine skeleton shows a regular extended conformation, while the spatial orientation of the phenol arms is governed by hydrogen bonds. In the 2-hydroxy-5-methylbenzaldehyde group, an intramolecularS(6) O—H...O hydrogen bond is observed between the alcohol and aldehyde functions, and the neighbouring phenol arm participates in an in

APA, Harvard, Vancouver, ISO, and other styles

24

Brock, C. P., and Y. Fu. "Pentachlorotoluene: Rotational and Compositional Disorder." Acta Crystallographica Section B Structural Science 53, no. 4 (1997): 613–19. http://dx.doi.org/10.1107/s0108768197004102.

Full text

Abstract:

The structure of pentachlorotoluene, which is isostructural with most other C6Cl n (CH3)_{6-n} derivatives, has been redetermined at 294 (1) K. The methyl group is distributed almost randomly among six sites; there is little discrimination between the Cl and CH3 substituents. The TL thermal-motion description suggests that the in-plane libration is moderate ( <\psi2> = 13 deg2); the barrier to in-plane rotation is estimated as 35 (3) kJ mol−1. Compositional disorder is a possibility.

APA, Harvard, Vancouver, ISO, and other styles

25

Rajalakshmi, P., N. Srinivasan, R. V. Krishnakumar, Ibrahim Abdul Razak, and Mohd Mustaqim Rosli. "Supramolecular sheets in (4H-chromeno[4,3-c]isoxazol-3-yl)methanol and its hydrated 8-methyl-substituted analogue at 100 K." Acta Crystallographica Section C Crystal Structure Communications 68, no. 11 (2012): o481—o484. http://dx.doi.org/10.1107/s0108270112043545.

Full text

Abstract:

The title compounds, (4H-chromeno[4,3-c]isoxazol-3-yl)methanol, C11H9NO3, (I), and (8-methyl-4H-chromeno[4,3-c]isoxazol-3-yl)methanol monohydrate, C12H11NO3·H2O, (II), crystallize in the monoclinic space groupsP21/candC2/c, respectively. The simple addition of a methyl substituent in (II) results in a change in the structure type and substantially alters the intermolecular interaction patterns, while retaining the point-group symmetry 2/m. Compound (II) crystallizes as a hydrate and the resulting hydrogen-bonding interactions involving the water molecule are the cause of differences in the hyd

APA, Harvard, Vancouver, ISO, and other styles

26

Destro, Riccardo, Pietro Roversi, Mario Barzaghi, and Leonardo Lo Presti. "Anharmonic Thermal Motion Modelling in the Experimental XRD Charge Density Determination of 1-Methyluracil at T = 23 K." Molecules 26, no. 11 (2021): 3075. http://dx.doi.org/10.3390/molecules26113075.

Full text

Abstract:

The experimental electron density distribution (EDD) of 1-methyluracil (1-MUR) was obtained by single crystal X-ray diffraction (XRD) experiments at 23 K. Four different structural models fitting an extensive set of XRD data to a resolution of (sinθ/λ)max = 1.143 Å−1 are compared. Two of the models include anharmonic temperature factors, whose inclusion is supported by the Hamilton test at a 99.95% level of confidence. Positive Fourier residuals up to 0.5 eÅ–3 in magnitude were found close to the methyl group and in the region of hydrogen bonds. Residual density analysis (RDA) and molecular dy

APA, Harvard, Vancouver, ISO, and other styles

27

Dhanalakshmi, G., Velu Saravanan, Arasambattu K. Mohanakrishnan, and S. Aravindhan. "Synthesis, Crystal Structure, Hirshfeld Surface, Energy Framework and Molecular Docking Analysis of Two Novel Carbazole Derivatives." Asian Journal of Chemistry 31, no. 12 (2019): 3017–28. http://dx.doi.org/10.14233/ajchem.2019.22430.

Full text

Abstract:

Carbazole derivatives are important compounds from medicinal point of view because of their widespread biological significance. In the present work two compounds 7-(4-chlorophenyl)-5-methyl- 12-(phenylsulfonyl)-12H-naphtho[1,2-b]carbazole (I) and 7-ethyl-5-methyl-12-(phenylsulfonyl)-12Hnaphtho[ 1,2-b]carbazole (II) have been synthesized and characterized by XRD, Hirshfeld surface, energy framework and docking analysis. Single crystal X-ray diffraction analysis shows that the compound I crystallizes in monoclinic system with space group P21/n whereas compound II crystallizes in triclinic with s

APA, Harvard, Vancouver, ISO, and other styles

28

Torgeson, Kristiane R., Michael W. Clarkson, Ganesan Senthil Kumar, Rebecca Page, and Wolfgang Peti. "Cooperative dynamics across distinct structural elements regulate PTP1B activity." Journal of Biological Chemistry 295, no. 40 (2020): 13829–37. http://dx.doi.org/10.1074/jbc.ra120.014652.

Full text

Abstract:

Protein-tyrosine phosphatase 1B (PTP1B) is the canonical enzyme for investigating how distinct structural elements influence enzyme catalytic activity. Although it is recognized that dynamics are essential for PTP1B function, the data collected thus far have not resolved whether distinct elements are dynamically coordinated or, alternatively, whether they fulfill their respective functions independently. To answer this question, we performed a comprehensive 13C-methyl relaxation study of Ile, Leu, and Val (ILV) residues of PTP1B, which, because of its substantially increased sensitivity, provi

APA, Harvard, Vancouver, ISO, and other styles

29

Velázquez-Carmona, Miguel-Ángel, Sylvain Bernès, Francisco Javier Ríos-Merino, and Yasmi Reyes Ortega. "Crystal structure oftrans-N,N′-bis(3,5-di-tert-butyl-2-hydroxyphenyl)oxamide methanol monosolvate." Acta Crystallographica Section E Crystallographic Communications 72, no. 7 (2016): 918–21. http://dx.doi.org/10.1107/s205698901600880x.

Full text

Abstract:

The here crystallized oxamide was previously characterized as an unsolvated species [Jímenez-Pérezet al.(2000).J. Organomet. Chem.614–615, 283–293], and is now reported with methanol as a solvent of crystallization, C30H44N2O4·CH3OH, in a different space group. The introduction of the solvent influences neither the molecular symmetry of the oxamide, which remains centrosymmetric, nor the molecular conformation. However, the unsolvated molecule crystallized as an ordered system, while many parts of the solvated crystal are disordered. The hydroxy group in the oxamide is disordered over two chem

APA, Harvard, Vancouver, ISO, and other styles

30

Shishkina, Svitlana V., Irina S. Konovalova, Sergiy M. Kovalenko, et al. "Influence of ortho-substituent on the molecular and crystal structures of 2-(N-arylimino)coumarin-3-carboxamide: isotypic and polymorphic structures." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 75, no. 5 (2019): 887–902. http://dx.doi.org/10.1107/s2052520619010485.

Full text

Abstract:

During a comprehensive study of a series of 2-(N-arylimino)coumarin-3-carboxamides with the aryl group substituted in the ortho-position by either a halogen atom, a methyl group or a methoxy group, the existence of three groups of isotypic crystal structures has been revealed. The similarity of crystal structures belonging to the same groups was confirmed by the analysis based on the comparison of pairwise interactions energies obtained from quantum chemical calculations. Group I includes unsubstituted, methyl-substituted and polymorphic modification 1 of fluoro-substituted 2-(N-arylimino)coum

APA, Harvard, Vancouver, ISO, and other styles

31

Malek, Tanvirbanu J., Sahaj A. Gandhi, Vijay Barot, Mukesh Patel, and Urmila H. Patel. "Crystal structure and Hirshfeld surface analysis of methyl 4-[(E)-2-(5-bromo-2-methoxybenzylidene)hydrazinyl]-3-nitrobenzoate." Acta Crystallographica Section E Crystallographic Communications 74, no. 9 (2018): 1239–43. http://dx.doi.org/10.1107/s2056989018011325.

Full text

Abstract:

The title compound, C16H14BrN3O5, is a novel halogen (Br) substituted hydrazine derivative. The hydrazine derivatives were the group of compounds with the general structure, R 1 R 2C=NNH2 (Uppal et al., 2011), with the central RC=NNH2 moiety bridging two different groups on both sides. An all-trans configuration of the backbone (RC=NNH2) results in an extended molecular conformation. The dihedral angle between the 5-bromo-2-methoxyphenyl ring and the nitrophenyl ring is 4.4 (3)°. Intramolecular N—H...O interactions form S(6) graph-set motifs, while C—H...O and C—H...N interactions form S(5) gr

APA, Harvard, Vancouver, ISO, and other styles

32

Reynhardt, E. C. "Phase Transitions and Molecular Reorientations in Bilayered n-Heptadecylammonium Chloride." Australian Journal of Physics 51, no. 3 (1998): 557. http://dx.doi.org/10.1071/p98001.

Full text

Abstract:

An investigation of phase transitions and molecular motions in polycrystalline n-heptadecylam- monium chloride (C17H35NH3Cl), employing differential scanning calorimetry, x-ray powder diffraction and nuclear magnetic resonance techniques, is reported. This compound can occur in two virgin polymorphs at room temperature, one interdigitated and one noninterdigitated. The temperature at which crystallisation occurs determines the polymorph that forms. If these polymorphs are heated transitions to noninterdigitated γ, β and α phases occur. Cooling to room temperature shows the same phase transitio

APA, Harvard, Vancouver, ISO, and other styles

33

Frey, Joseph, Saeed I. Khan, Carolyn B. Knobler, et al. "Thermal motion of tert-butyl groups III. tert-Butyl substituents in aromatic hydrocarbons, the view from the bottom of the well." Acta Crystallographica Section B Structural Science 66, no. 6 (2010): 622–38. http://dx.doi.org/10.1107/s0108768110040024.

Full text

Abstract:

The rigidity of the tert-butyl group (TBG) as a substituent in aromatic hydrocarbons is investigated, with a modified Hirshfeld test of anisotropic displacement parameters (ADPs) as a primary criterion. Four new structures are analyzed, along with low-temperature studies of a previously published crowded supermesityl dimer; three of the five structures meet the primary test. Most of the TBGs meet the Hirshfeld test at 100 K, and the ADPs are improved by omitting low-order data in the final refinement. The three most precise structures yield a wide variation in libration amplitudes (and in esti

APA, Harvard, Vancouver, ISO, and other styles

34

Yang, Danya, Thomas Eggimann, Hal Wieser, Arvi Rauk, and Gennadii Shustov. "Local and framework stereochemical markers in vibrational circular dichroism: 1,2- and 2,3-dimethylaziridines." Canadian Journal of Chemistry 71, no. 12 (1993): 2028–37. http://dx.doi.org/10.1139/v93-252.

Full text

Abstract:

The vibrational circular dichroism (VCD) spectra of 2,3-dimethylaziridine 1 and 1,2-dimethylaziridine 2 were measured experimentally and interpreted with the help of ab initio Vibronic Coupling Theory (VCT) both in the common origin (CO) and distributed origin (DO) gauge. The absolute magnitudes of the VCD intensities by the VCT-CO method in the mid-IR range are closer to the experimental measurement. Both VCT-DO and VCT-CO methods, however, predict the same signs for almost all VCD bands. In general, both VCT-DO and VCT-CO methods predict VCD and IR spectra that are both in good agreement wit

APA, Harvard, Vancouver, ISO, and other styles

35

Takayanagi, Masao, and Ichiro Hanazaki. "Stimulated-Emission-Pumping Laser-Induced-Fluorescence Spectroscopy of Phenol and Anisole." Laser Chemistry 14, no. 1-3 (1994): 103–17. http://dx.doi.org/10.1155/1994/21635.

Full text

Abstract:

The SEP–LIF (stimulated emission pumping-laser induced fluorescence) technique was applied to the investigation of dynamical behavior of vibrationally excited phenol and anisole produced in the supersonic expansion. In the SEP–LIF scheme, a molecule excited to a specific vibrational state by SEP is detected by measuring the LIF excitation spectrum with an appropriate delay to probe the vibrational relaxation. Four vibrational states, 6a1, 16a2, 121 and 11, of phenol, and six vibrational states, 18b1, 18b2, 6a1, 121, 16a2 and 11, of anisole were investigated. For both of phenol and anisole, it

APA, Harvard, Vancouver, ISO, and other styles

36

Zajíček, Jaroslav, Jeffrey F. Ellena, Gerald D. Williams, Mohammad A. Khadim, and Michael F. Brown. "Molecular Dynamics of Vesicles of Unsaturated Phosphatidylcholines Studied by 13C NMR Spin-Lattice Relaxation." Collection of Czechoslovak Chemical Communications 60, no. 5 (1995): 719–35. http://dx.doi.org/10.1135/cccc19950719.

Full text

Abstract:

13C spin-lattice relaxation times, T1Z, were measured at four different magnetic field strengths for a vesicles of a series of unsaturated 1,2-diacyl-sn-glycero-3-phosphocholines over the temperature range from 5 to 50 °C. The acyl chains of the phosphatidylcholines varied in length from 14 to 18 carbons and in the degree of unsaturation: myristoleoyl (14 : 1), palmitoleoyl (16 : 1), oleoyl (18 : 1), linoleoyl (18 : 2), linolenoyl (18 : 3). For each of the phosphatidylcholines studied the R1Z = (NT1Z)-1 values of the acyl chain methylene carbons, where N is the number of directly bonded hydrog

APA, Harvard, Vancouver, ISO, and other styles

37

Kreiter, Cornelius G., Klaus Lehr та Gerhard Heeb. "Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XXXVIII [1]. [4+5]-Cycloaddition von 2,3-Dimethyl-1,3-butadien an Tricarbonyl- η5-2,4-pentadienyl-mangan und Tricarbonyl-η5-dimethyl-2,4-pentadienyl-mangan / Hindered Ligand Motions in Transition Metal Complexes, XXXVIII [1]. [4+5] Cycloaddition of 2,3-Dimethyl-1,3-butadiene to Tricarbonyl(η5 -2 ,4 -pentadienyl)manganese and Tricarbonyl(η5 -2 ,4 -dimethyl-2 ,4 -pentadienyl)manganese". Zeitschrift für Naturforschung B 46, № 7 (1991): 941–49. http://dx.doi.org/10.1515/znb-1991-0713.

Full text

Abstract:

Tricarbonyl(η5-2,4-pentadienyl)manganese (1) and tricarbonyl(η5-2,4-dimethyl-2,4-pentadienyl)manganese (2) photochemically add 2,3-dimethyl-1,3-butadiene (3). Mediated by manganese, 6,7-dimethyl-2,6-cyclononadiene-1-yl and 1,3,6,7-tetramethyl-2,6-cyclononadiene-1-yl complexes are formed. Η-shifts from the methyl groups of the substituted CC double bonds convert the primary products into tricarbonyl-η3:CH-l-methylene-2-methyl-6-cyclononen-2-ylmanganese (4), and tricarbonyl-η3:CH-1-methylene-2,5,7-trimethyl-6-cyclononen-2-yl-manganese (6), respectively. In addition tetracarbonyl-η3-1-methylene-2

APA, Harvard, Vancouver, ISO, and other styles

38

Schaefer, Ted, and Glenn H. Penner. "Mechanisms of long-range 13C, 13C spin–spin coupling in thioanisole and its derivatives. Conformational applications." Canadian Journal of Chemistry 66, no. 5 (1988): 1229–38. http://dx.doi.org/10.1139/v88-201.

Full text

Abstract:

The 13C nuclear magnetic resonance chemical shifts and the long-range 13C,13C spin–spin coupling constants are reported for 23 thioanisole derivatives enriched in 13C at the methyl position. For para and meta substituted thioanisole derivatives, nJ(C,C) (n being the formal number of bonds intervening between the coupled nuclei) can be related to functions of the angle by which the thiomethyl group twists out of the aromatic plane. For n = 3,4,5, the ensuing relationships yield estimates of the twofold barriers to rotation about the C(1)—S bond. The barrier is lower in ethyl phenyl sulfide than

APA, Harvard, Vancouver, ISO, and other styles

39

Moers, Oliver, Armand Blaschette, Violeta Latorre, and Peter G. Jones. "Polysulfonylamine, Clxxv [1]. Intermolekulare Wechselwirkungen In Kristallinen Di(Organosulfonyl)Aminen. Teil 3 [2]. Supramolekulare Strukturen Von Di(Benzolsulfonyl)Amin, (Benzolsulfonyl)(Methansulfonyl)Amin Und Di(Ethansulfonyl)Amin." Zeitschrift für Naturforschung B 61, no. 8 (2006): 923–34. http://dx.doi.org/10.1515/znb-2006-0801.

Full text

Abstract:

Low-temperature X-ray structures of the following di(organosulfonyl)amines, HN(SO2R)(SO2R’), are compared in order to study the packing effects of group-specific intermolecular interactions: R = R’ = phenyl (1, monoclinic, P21/c, Z' = 1); R = phenyl, R’ = methyl (2, monoclinic, P21/n, Z' = 1); R = R’ = ethyl (3, monoclinic, P21/c, Z' = 1). The molecules of each compound are associated into catemers by N-H···O hydrogen bonds of graph set C(4). These catemers form molecular layers via distinctive cross-linking modes, which underline the specific propensity of the organic groups to establish dire

APA, Harvard, Vancouver, ISO, and other styles

40

Koné, Soleymane, Nicolas Galland, El-Hadji Sawaliho Bamba, and Jean-Yves Le Questel. "Hydrogen-bonding properties of galanthamine: an investigation through crystallographic database observations and computational chemistry." Acta Crystallographica Section B Structural Science 64, no. 3 (2008): 338–47. http://dx.doi.org/10.1107/s010876810800709x.

Full text

Abstract:

The hydrogen-bonding properties of galanthamine have been investigated experimentally from a thorough analysis of crystallographic data retrieved from the Protein Data Bank and Cambridge Structural Database databases and theoretically through ab initio [MP2/6-311++G(2d,p)] and density functional theory [MPWB1K/6-31++G(d,p)] calculations. The main hydrogen-bond acceptor (HBA) interaction sites of the molecule are the O atoms and their spatial proximity allows multi-centered hydrogen-bond (HB) motifs. The hydrogen-bond donor (HBD) sites of the molecule are the NH+ and OH groups as well as severa

APA, Harvard, Vancouver, ISO, and other styles

41

Senent, María Luisa, and Samira Dalbouha. "Large Amplitude Motions of Pyruvic Acid (CH3-CO-COOH)." Molecules 26, no. 14 (2021): 4269. http://dx.doi.org/10.3390/molecules26144269.

Full text

Abstract:

Torsional and rotational spectroscopic properties of pyruvic acid are determined using highly correlated ab initio methods and combining two different theoretical approaches: Second order perturbation theory and a variational procedure in three-dimensions. Four equilibrium geometries of pyruvic acid, Tc, Tt, Ct, and CC, outcome from a search with CCSD(T)-F12. All of them can be classified in the Cs point group. The variational calculations are performed considering the three internal rotation modes responsible for the non-rigidity as independent coordinates. More than 50 torsional energy level

APA, Harvard, Vancouver, ISO, and other styles

42

Swaminathan, K., P. Narayanan, K. Sethusankar, Velu Saravanan, and Arasambattu K. Mohanakrishnan. "Crystal structures of two new carbazole derivatives: 12-(4-nitrophenyl)-7-phenylsulfonyl-7H-benzofuro[2,3-b]carbazole and 2-methyl-4-(4-nitrophenyl)-9-phenylsulfonyl-9H-thieno[2,3-b]carbazole." Acta Crystallographica Section E Crystallographic Communications 72, no. 12 (2016): 1739–43. http://dx.doi.org/10.1107/s2056989016016996.

Full text

Abstract:

The title compounds, C30H18N2O5S, (I), and C27H18N2O4S2, (II), are carbazole derivatives with a phenylsulfonyl group and a nitrophenyl group attached to the carbazole moiety in identical positions in both molecules. A benzofuran ring system in (I) and a methylthiophene ring in (II) are fused with the respective carbazole moieties on the same sides. The mean plane of the carbazole ring system makes a dihedral angle of 3.17 (7)° with the benzofuran ring system in (I) and a dihedral angle of 3.39 (11)° with the methylthiophene ring in (II), implying that both fused units are essentially planar. T

APA, Harvard, Vancouver, ISO, and other styles

43

Prabha, E. Arockia Jeya Yasmi, S. Suresh Kumar, Anil K. Padala, Qazi Naveed Ahmed, and S. Athimoolam. "Crystal structure of ethyl 2-[2-(4-methylbenzoyl)-5-p-tolyl-1H-imidazol-1-yl]acetate." Acta Crystallographica Section E Crystallographic Communications 72, no. 3 (2016): 347–49. http://dx.doi.org/10.1107/s2056989016002504.

Full text

Abstract:

In the title compound, C22H22N2O3, the plane of the five-membered ring is oriented at dihedral angles of 45.4 (1) and 52.5 (1)° to the phenyl rings. Furthermore, this ring makes an angle of 85.2 (2)° with the plane of the ethyl acetate substituent. The molecular structure is affected by an intramolecular C—H...O hydrogen bond between an H atom from thep-tolyl group and the carbonyl O atom of the acetate. The methyl group of the ethyl acetate residue is disordered over two sites with equal occupancies. The crystal structure features intermolecular C—H...O and C—H...N interactions. One of the C—

APA, Harvard, Vancouver, ISO, and other styles

44

Searle, M. S., J. G. Hall, and P. G. Wakelin. "1H- and 13C-n.m.r. studies of the antitumour antibiotic luzopeptin. Resonance assignments, conformation and flexibility in solution." Biochemical Journal 256, no. 1 (1988): 271–78. http://dx.doi.org/10.1042/bj2560271.

Full text

Abstract:

The depsipeptide DNA-intercalating antibiotic luzopeptin was studied in solution by n.m.r. methods. Two-dimensional 1H double-quantum-filtered correlation spectroscopy (DQF-COSY) and nuclear-Overhauser-effect spectroscopy (NOESY) confirm the primary structure and twofold symmetry of luzopeptin and provide details of its three-dimensional conformation in solution. Trans-annular hydrogen bonds between the glycine NH groups and carbonyl oxygen atoms have been identified in the crystalline state [Arnold & Clardy (1981) J. Am. Chem. Soc. 103, 1243-1244], and are important in maintaining an anti

APA, Harvard, Vancouver, ISO, and other styles

45

Selesi, Draženka, Nico Jehmlich, Martin von Bergen, et al. "Combined Genomic and Proteomic Approaches Identify Gene Clusters Involved in Anaerobic 2-Methylnaphthalene Degradation in the Sulfate-Reducing Enrichment Culture N47." Journal of Bacteriology 192, no. 1 (2009): 295–306. http://dx.doi.org/10.1128/jb.00874-09.

Full text

Abstract:

ABSTRACT The highly enriched deltaproteobacterial culture N47 anaerobically oxidizes the polycyclic aromatic hydrocarbons naphthalene and 2-methylnaphthalene, with sulfate as the electron acceptor. Combined genome sequencing and liquid chromatography-tandem mass spectrometry-based shotgun proteome analyses were performed to identify genes and proteins involved in anaerobic aromatic catabolism. Proteome analysis of 2-methylnaphthalene-grown N47 cells resulted in the identification of putative enzymes catalyzing the anaerobic conversion of 2-methylnaphthalene to 2-naphthoyl coenzyme A (2-naphtho

APA, Harvard, Vancouver, ISO, and other styles

46

Chew, Aline Gomez Maqueo, Niels-Ulrik Frigaard, and Donald A. Bryant. "Bacteriochlorophyllide c C-82 and C-121 Methyltransferases Are Essential for Adaptation to Low Light in Chlorobaculum tepidum." Journal of Bacteriology 189, no. 17 (2007): 6176–84. http://dx.doi.org/10.1128/jb.00519-07.

Full text

Abstract:

ABSTRACT Bacteriochlorophyll (BChl) c is the major photosynthetic pigment in the green sulfur bacterium Chlorobaculum tepidum, in which it forms protein-independent aggregates that function in light harvesting. BChls c, d, and e are found only in chlorosome-producing bacteria and are unique among chlorophylls because of methylations that occur at the C-82 and C-121 carbons. Two genes required for these methylation reactions were identified and designated bchQ (CT1777) and bchR (CT1320). BchQ and BchR are members of the radical S-adenosylmethionine (SAM) protein superfamily; each has sequence m

APA, Harvard, Vancouver, ISO, and other styles

47

Hakiri, Rihab, Najoua Derbel, Ha Vinh Lam Nguyen, and Halima Mouhib. "Communication through the furan ring: the conformational effect on the internal rotation of 5-methyl furfural studied by microwave spectroscopy." Physical Chemistry Chemical Physics 20, no. 40 (2018): 25577–82. http://dx.doi.org/10.1039/c8cp04563a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Thanbichler, Martin, Bernhard Neuhierl, and August Böck. "S-Methylmethionine Metabolism in Escherichia coli." Journal of Bacteriology 181, no. 2 (1999): 662–65. http://dx.doi.org/10.1128/jb.181.2.662-665.1999.

Full text

Abstract:

ABSTRACT Selenium-accumulating Astragalus spp. contain an enzyme which specifically transfers a methyl group fromS-methylmethionine to the selenol of selenocysteine, thus converting it to a nontoxic, since nonproteinogenic, amino acid. Analysis of the amino acid sequence of this enzyme revealed thatEscherichia coli possesses a protein (YagD) which shares high sequence similarity with the enzyme. The properties and physiological role of YagD were investigated. YagD is anS-methylmethionine: homocysteine methyltransferase which also accepts selenohomocysteine as a substrate. Mutants inyagD which

APA, Harvard, Vancouver, ISO, and other styles

49

Kamaraj, A., S. Ranjith, R. Rajkumar, G. Mohanraj, and K. Krishnasamy. "Crystal structure of 1-cyclopropanecarbonyl-3-methyl-2,6-di-p-tolylpiperidin-4-one." Acta Crystallographica Section E Structure Reports Online 70, no. 9 (2014): o1056—o1057. http://dx.doi.org/10.1107/s1600536814018546.

Full text

Abstract:

The title compound, C24H27NO2, crystallizes with two independent molecules (AandB) in the asymmetric unit. The two molecules have very similar conformations and each exhibits an intramolecular C—H...π interaction. The central piperidine rings adopt boat conformations and thep-tolyl rings are inclined to the mean plane of the piperidine ring by 71.21 (11) and 89.86 (12)° in moleculeAand by 68.01 (12) and 89.33 (12)° in moleculeB. The cyclopropanecarbonyl group is oriented at an angle of 68.5 (2)° with respect to the mean plane of the piperidine ring in moleculeAand 66.2 (2)° in moleculeB. In th

APA, Harvard, Vancouver, ISO, and other styles

50

Raza, Ali, Wei Su, Ang Gao, et al. "Catalase (CAT) Gene Family in Rapeseed (Brassica napus L.): Genome-Wide Analysis, Identification, and Expression Pattern in Response to Multiple Hormones and Abiotic Stress Conditions." International Journal of Molecular Sciences 22, no. 8 (2021): 4281. http://dx.doi.org/10.3390/ijms22084281.

Full text

Abstract:

Catalase (CAT) is an antioxidant enzyme expressed by the CAT gene family and exists in almost all aerobic organisms. Environmental stresses induce the generation of reactive oxygen species (ROS) that eventually hinder plant growth and development. The CAT enzyme translates the hydrogen peroxide (H2O2) to water (H2O) and reduce the ROS levels to shelter the cells’ death. So far, the CAT gene family has not been reported in rapeseed (Brassica napus L.). Therefore, a genome-wide comprehensive analysis was conducted to classify the CAT genes in the rapeseed genome. The current study identified 14

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!