Molecular dynamics of tert-butyl chloride confined in CPG studied by NMR

Wasyluk, Lidia; Peplińska, Barbara; Jurga, Stefan

doi:10.1016/j.ssnmr.2003.03.028

Cited by 2 publications

(7 citation statements)

References 32 publications

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“…The reduction is larger for 7.4 nm pore size, showing increasing restriction of the translational motion and tumbling with the reduced pore size. These results are in agreement with previous observations [1,2] and those given in literature [5,6,8]. Below the temperature of the solid I -solid II phase transition of TBC confined to 15.6 nm CPG, two spin-lattice relaxation components are revealed by proton and deuteron data.…”

Section: Spin-lattice Relaxationsupporting

confidence: 93%

“…The linewidths of the broad components are nearly constant up to 138 K and than grow continuously, reflecting the decreasing in the rate of the molecular reorientations C 3 and C 3 . We have made similar observations in previous investigations of TBC confined to other sizes CPG and other types of pores [1,2].…”

Section: 3supporting

confidence: 88%

“…The derived activation energies considered in the context of the change induced by confinement effects are lower than in bulk for all molecular groups but taking into account preexponential factor values, the molecular motion of the tert--butyl groups is slower. The fact that the energies of the tert-butyl reorientation are much lower than in the bulk TBC and lower than for TBC confined to larger pore diameter [2], may result from a decrease of the intermolecular interactions in the bulk liquid phase of confined TBC. The slowing down of the motion can be due to the geometrical restrictions and is dependent on the degree of reduction of the pore width.…”

Section: Spin-lattice Relaxationmentioning

confidence: 94%

“…The specific surface area measured by nitrogen adsorption equals 153 m 2 /g for 7.5 nm and 91 m 2 /g for 15.6 nm CPG. The sample preparation has been described in the previous papers [1,2].…”

Section: H Andmentioning

confidence: 99%

“…where all parameters have their usual meaning [1,2]. It is sufficient to assume the existence of only two kinds of tert-butyl groups in bulk-like phase of TBC in both 15.6 and 7.4 nm CPG.…”

Section: Spin-lattice Relaxationmentioning

confidence: 99%

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Molecular Dynamics of Tert-butyl Chloride Confined to CPG (7.4, 15.6 nm)

2005

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The paper complements our earlier NMR investigation of molecular dynamics of tert-butyl chloride restricted by geometries of the type MCM-41 and CPG by the new sizes of CPG and by differential scanning calorimetry method. We report proton and deuteron NMR lineshapes and the spin--lattice relaxation results of tert-butyl chloride in CPG of the 15.6 nm and 7.4 nm pore diameter in the temperature range 70 K ≤ T ≤ 292 K. The bulk-like component of the confined tert-butyl chloride, in temperatures corresponding to phase III, is interpreted as a composition of two dynamically different subphases. The parameters of motions of both subphases are derived. The tert-butyl group motion in both subphases is more restricted than in the bulk tert-butyl chloride, although the activation energies are lower. Differential scanning calorimetry was used to determine temperatures of the phase transitions (140 K ≤ T ≤ 292 K). The results show that the depression of the phase transition temperature is pore size dependent and that the confinement has less influence on transition to the plastic phase than on the freezing and on the solid II -solid III transition.

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Section: Spin-lattice Relaxationsupporting

confidence: 93%

Section: 3supporting

confidence: 88%

Section: Spin-lattice Relaxationmentioning

confidence: 94%

Section: H Andmentioning

confidence: 99%

“…where all parameters have their usual meaning [1,2]. It is sufficient to assume the existence of only two kinds of tert-butyl groups in bulk-like phase of TBC in both 15.6 and 7.4 nm CPG.…”

Section: Spin-lattice Relaxationmentioning

confidence: 99%

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Molecular Dynamics of Tert-butyl Chloride Confined to CPG (7.4, 15.6 nm)

2005

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Solid-State NMR Spectroscopy Study of Molecular Dynamics of Pyridine 1-Oxide Encapsulated in p-tert-Butylcalix[4]arene

Nobleman

2020

J. Phys. Chem. A

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The mixture of guests 25% pyridine 1-oxide (PNO) and 75% nitrobenzene (NB) encapsulated in a host cavity of p-tert-butylcalix [4]arene (p-tBC) is a suitable system for the study of intermolecular weak interactions, and the preferred orientation of the guest molecules within the host was derived. Variable temperature deuterium nuclear magnetic resonance line shape and spin−lattice relaxation studies were performed on three samples of 25% PNO as a guest (selectively and entirely deuterated) with 75% NB encapsulated in p-tBC as a host system. It is found that the PNO molecular motion supports the two-site jump model and is highly mobile throughout the temperature range from −130 to 20 °C. PNO reorients about its C 2 molecular symmetry axis followed by reorientation around the compound's C 4 axis of symmetry of a host. Calculation showed that besides precise molecular jumping, the guest also experiences the vibrational motion with a variation angle dispute about 15°. The correlation times for the molecular guest motion and two-dimensional exchange spectroscopy confirmed a fast exchange limit inside the cavity. These molecular dynamics follow an Arrhenius behavior motion from which the small activation energy is delivered that strongly suggests a relatively weak intermolecular interaction between the host and guest species. PNO has definite dipole orientational motion in the cavity where its aromatic covalent bond structure minimizes contact with the host p-tert-butyl groups. Experimentally found, PNO-d 5 deuterons in the single crystal collapse at 55 and 125°at ambient temperature. The first splitting of 124 kHz belongs to D 3 (D 5 ), the second splitting of 100 kHz belongs to D 2 (D 6 ), and the last splitting of 52 kHz belongs to D 4 of the ring of PNO inside the p-tBC.

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Molecular dynamics of tert-butyl chloride confined in CPG studied by NMR

Cited by 2 publications

References 32 publications

Molecular Dynamics of Tert-butyl Chloride Confined to CPG (7.4, 15.6 nm)

Molecular Dynamics of Tert-butyl Chloride Confined to CPG (7.4, 15.6 nm)

Solid-State NMR Spectroscopy Study of Molecular Dynamics of Pyridine 1-Oxide Encapsulated in p-tert-Butylcalix[4]arene

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