Nonexponential solid state 1H and 19F spin-lattice relaxation, single-crystal X-ray diffraction, and isolated-molecule and cluster electronic structure calculations in an organic solid: coupled methyl group rotation and methoxy group libration in 4,4'-dimethoxyoctafluorobiphenyl.

doi:10.1021/jp3075892

Paper

Nonexponential solid state 1H and 19F spin-lattice relaxation, single-crystal X-ray diffraction, and isolated-molecule and cluster electronic structure calculations in an organic solid: coupled methyl group rotation and methoxy group libration in 4,4'-dimethoxyoctafluorobiphenyl.

Published Nov 20, 2012 · Donald P. Fahey, William G. Dougherty, W. Kassel

The journal of physical chemistry. A

Q2 SJR score

10

Citations

0

Influential Citations

Open Access PDF Full text Semantic Scholar

Abstract

We investigate the relationship between intramolecular rotational dynamics and molecular and crystal structure in 4,4'-dimethoxyoctafluorobiphenyl. The techniques are electronic structure calculations, X-ray diffractometry, and (1)H and (19)F solid state nuclear magnetic resonance relaxation. We compute and measure barriers for coupled methyl group rotation and methoxy group libration. We compare the structure and the structure-motion relationship in 4,4'-dimethoxyoctafluorobiphenyl with the structure and the structure-motion relationship in related compounds in order to observe trends concerning the competition between intramolecular and intermolecular interactions. The (1)H spin-lattice relaxation is nonexponential in both the high-temperature short-correlation time limit and in the low-temperature long-correlation time limit, albeit for different reasons. The (19)F spin-lattice relaxation is nonexponential at low temperatures and it is exponential at high temperatures.

Study Snapshot

In 4,4'-dimethoxyoctafluorobiphenyl, intramolecular rotational dynamics influence the structure and dynamics, with different reasons for nonexponential relaxation in different temperatures.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Sign up to use Study Snapshot

Consensus is limited without an account. Create an account or sign in to get more searches and use the Study Snapshot.

Create an account

Paper

Nonexponential solid state 1H and 19F spin-lattice relaxation, single-crystal X-ray diffraction, and isolated-molecule and cluster electronic structure calculations in an organic solid: coupled methyl group rotation and methoxy group libration in 4,4'-dimethoxyoctafluorobiphenyl.

Sign up to use Study Snapshot

References

Single-crystal X-ray diffraction, isolated-molecule and cluster electronic structure calculations, and scanning electron microscopy in an organic solid: models for intramolecular motion in 4,4'-dimethoxybiphenyl.

The crystal structure of 4,4'-dimethoxybiphenyl shows that intermolecular interactions lower the barrier for coupled methyl-group rotation and methoxy-group libration, suggesting a lower barrier in the crystal.

Multinuclear NMR relaxometry studies in singly fluorinated liquid crystal

1H and 19F in fluorinated liquid crystal exhibit distinct relaxation pathways, sensitivity to different time modulations, and field-cycling technique allows for cross-relaxation in strong coupling limit.

Accurate Hydrogen Positions in Organic Crystals: Assessing a Quantum-Chemical Aide

Selective relaxation of hydrogen positions in organic crystals using plane-wave density-functional computations aligns well with neutron diffraction results, justifying its use for accurate hydrogen positions in organic crystals.

Intramolecular and intermolecular contributions to the barriers for rotation of methyl groups in crystalline solids: electronic structure calculations and solid-state NMR relaxation measurements.

Methyl rotation barriers in crystalline solids range from 0.6 to 3.4 kcal/mol, with intramolecular and intermolecular contributions varying from 0.0 to 1.0 kcal/mol.

A proton spin-lattice relaxation rate study of methyl and t-butyl group reorientation in the solid state.

Methyl and t-butyl group rotation modulates spin-spin interactions in solid state, with the 2-methyl groups rotating fast even at low temperatures.

Citations

Partition of electronic excitation energies: the IQA/EOM-CCSD method.

The IQA/EOM-CCSD method provides valuable insights into molecular changes induced by electron excitation, aiding in the rational design of tailored photoexcitations in photophysics and photochemistry.

(1)H and (19)F spin-lattice relaxation and CH3 or CF3 reorientation in molecular solids containing both H and F atoms.

This study investigates the dynamics of methyl (CH3) and fluoromethyl (CF3) groups in organic solids, providing more information than when only one spin species (usually (1)H) is present.

Methyl and t-butyl group rotation in a molecular solid: (1)H NMR spin-lattice relaxation and X-ray diffraction.

Solid state (1)H relaxation experiments and X-ray diffraction reveal the dynamics of t-butyl groups and their constituent methyl groups in 2-t-butyldimethylsilyloxy-6-bromonaphthalene.

Nonexponential (1)H spin-lattice relaxation and methyl group rotation in molecular solids.

Nonexponential 1H spin-lattice relaxation results from methyl group rotation in polycrystalline van der Waals solids, highlighting the need for accurate reporting of such measurements.

Methoxy and Methyl Group Rotation: Solid-State NMR (1) H Spin-Lattice Relaxation, Electronic Structure Calculations, X-ray Diffractometry, and Scanning Electron Microscopy.

This study uses solid-state NMR relaxation measurements, X-ray diffractometry, and scanning electron microscopy to investigate the rotation of methoxy groups and their constituent methyl groups in 1-methoxyphenanthrene and 3-methoxyphenanthrene compounds.

Solid state ¹H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: the relationship between structure and methyl group and t-butyl group rotation.

T-butyl groups in organic molecular solids exhibit unusual ground state orientation and high rotational barriers, with a dynamical model for superposition of t-butyl group rotation and methyl group rotation.