Deuterium nuclear magnetic resonance line-shape study of structure and mobility in a solid benzene-cyclophosphazene inclusion compound

Meirovitch, Eva; Belsky, Igal; Vega, Shimon

doi:10.1021/j150652a016

Cited by 29 publications

(40 citation statements)

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“…The channels are locally triangular, with the triangles rotated 60 from one layer to the next. Inclusion compounds of TPP with numerous small molecules such as alkanes or benzene have a venerable history in host-guest chemistry [49][50][51][52][53][54][55][56][57][58]. A monoclinic modification of TPP [50,53] that does not form inclusion compounds is also known and below~150 C it is actually more stable than the empty hexagonal form.…”

Section: The Host: Tppmentioning

confidence: 99%

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

Zhao

Dron

Kaleta

et al. 2014

Molecular Machines and Motors

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Regular two-dimensional or three-dimensional arrays of mutually interacting dipolar molecular rotors represent a worthy synthetic objective. Their dielectric properties, including possible collective behavior, will be a sensitive function of the location of the rotors, the orientation of their axes, and the size of their dipoles. Host-guest chemistry is one possible approach to gaining fine control over these factors. We describe the progress that has been achieved in recent years using tris (o-phenylenedioxy)cyclotriphosphazene as a host and a series of rod-shaped dipolar molecular rotors as guests. Structures of both surface and bulk inclusion compounds have been established primarily by solid-state nuclear magnetic resonance (NMR) and powder X-ray diffraction (XRD) techniques. Low-temperature dielectric spectroscopy revealed rotational barriers as low as 1.5 kcal/mol, but no definitive evidence for collective behavior has been obtained so far.

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Section: The Host: Tppmentioning

confidence: 99%

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

Zhao

Dron

Kaleta

et al. 2014

Molecular Machines and Motors

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“…The characterization of the orientation and of the dynamics of guest molecules in inclusion compounds has attracted considerable attention in recent years (see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13]). Nuclear magnetic resonance (NMR), in particular 2H-NMR, has been applied frequently in this context [1][2][3][4][5][6][7][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…Nuclear magnetic resonance (NMR), in particular 2H-NMR, has been applied frequently in this context [1][2][3][4][5][6][7][9][10][11][12]. In most of such studies polycrystalline samples were used.…”

Section: Introductionmentioning

confidence: 99%

The orientations and dynamics of ethanol guest molecules in the clathrate of Dianin's compound

1992

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In the clathrates of Dianin's compound the guests are trapped in cages formed by six host molecules. Two ethanol molecules can be enclosed by each cage. Deuteron nuclear magnetic resonance spectra of single crystals of Dianin's compound with ethanol-OD, ethanol-l,l-D2 and ethanol-2,2,2-D 3 as a guest were recorded in the temperature range 10K < T< 310K. Only at T < 25 K the guests are found to be immobile enough to allow the determination of the bond directions of the different deuterons from the unique eigenvectors of the quadrupole coupling (qc) tensors. The measured qc tensors of the hydroxyl and of the methylene deuterons are used to determine the orientations of the ethanol molecules as a whole. These can occupy six distinct sites. The two ethanol molecules in a given cage are linked by a weak hydrogen bond. The dynamics of the ethanol guests is elucidated by line shape analyses and by deuteron two-dimensional exchange spectroscopy. It is found to be rather complex, consisting of three different types of large-angle reorientations of the entire ethanol molecules, of internal reorientations of the methyl groups about their local C3 axes and of additional librational and torsional motions. The average equilibrium orientations of the ethanol molecules change with increasing temperature. The observed dynamics implies that the host lattice of the clathrate possesses a considerable degree of flexibility, in particular it must enable the two ethanol molecules within a given cage to exchange places, or to diffuse from one cage to the next.

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“…Accordingly, we found that each guest molecule assumes an extended all-trans configuration and undergoes reorientation about the molecular long axis. The activation energies for n-hexane and n-decane were estimated to be (20 2) kJ mol 1 and (30 2) kJ mol 1 , respectively, suggesting that the interaction energy between the CD 3 or CD 2 group and the pore wall amounts to about 3 kJ mol 1 .…”

Section: Resultsmentioning

confidence: 99%

“…Among them were compounds based on micro-and meso-porous media. Various studies of the behavior of the guest molecules adsorbed in a variety of inclusion compounds [1,2] and / or the zeolite family [3 -8] were reported. The structure and dynamics of the guest molecules accommodated in these porous media depend strongly on the size and the shape of the pores as well as the kind of the host material.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of some n-Alkanes Adsorbed in the Micropore of (±)-[Co(en)₃]Cl₃ as Studied by ²H NMR

Nagaoka

Ueda

Nakamura

2002

Zeitschrift Für Naturforschung A

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The dynamic behavior of n-hexane-d 14 and n-decane-d 22 , adsorbed in the micropore of [Co(en) 3 ]Cl 3 crystal was studied by 2 H 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 CD 2 group in hexane decreases from 160 kHz to 80 kHz on heating up to 170 K. Similar reduction of QCC of CD 2 observed above 280 K for decane. Assuming the three-site jump model of the guest molecule about its molecular long axis, we reproduced the experimental spectrum, and obtained the rate of the molecular motion in each guest. The temperature dependence of jump rates leads to the activation energies for the molecular reorientation of 20 kJ mol 1 and 30 kJ mol 1 for n-hexane and n-decane, respectively, suggesting that the length of the guest molecule influences greatly its dynamics in the micropore.

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Deuterium nuclear magnetic resonance line-shape study of structure and mobility in a solid benzene-cyclophosphazene inclusion compound

Cited by 29 publications

References 0 publications

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

The orientations and dynamics of ethanol guest molecules in the clathrate of Dianin's compound

Dynamics of some n-Alkanes Adsorbed in the Micropore of (±)-[Co(en)₃]Cl₃ as Studied by ²H NMR

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Deuterium nuclear magnetic resonance line-shape study of structure and mobility in a solid benzene-cyclophosphazene inclusion compound

Cited by 29 publications

References 0 publications

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

Arrays of Dipolar Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene

The orientations and dynamics of ethanol guest molecules in the clathrate of Dianin's compound

Dynamics of some n-Alkanes Adsorbed in the Micropore of (±)-[Co(en)3]Cl3 as Studied by 2H NMR

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Dynamics of some n-Alkanes Adsorbed in the Micropore of (±)-[Co(en)₃]Cl₃ as Studied by ²H NMR