Electronic Resource
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
95 (1991), S. 2696-2701
ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
1H nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation data as well as 1H decoupled 13C spectra have been utilized to study the dynamics of the molecular disorder in solid 9-hydroxyphenalenone. In the room-temperature phase—stable between 255 and 380 K—the proton spectrum is narrowed compared to the spectrum of a static structure. This is consistent with a dynamically disordered structure where one of the two nonequivalent molecules reorients rapidly between its two possible equilibrium orientations. The proton spin-lattice relaxation has a maximum of 7.2 s−1 in the same phase at about 355 K, in close agreement with a value of 7.6 s−1 calculated from the dynamical disorder model. The 1H decoupled 13C powder spectrum in the room-temperature phase is also consistent with this picture. Above the 385 K phase transition, the 13C powder spectrum is approaching axial symmetry, proving that all molecules reorient rapidly in that phase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.460921
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