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Adamantane as a probe for studies of spin clustering with multiple quantum NMR

Buntkowsky, G. and Roessler, E. and Taupitz, M. and Vieth, H. M. (1997):
Adamantane as a probe for studies of spin clustering with multiple quantum NMR.
In: Journal of Physical Chemistry A, 101 (1), pp. 67-75, [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

Time domain H-1 multiple quantum NMR (MQ NMR) was applied to study binary guest/host systems. We investigated protonated adamantane-h(16) (A-h(16)) molecules in deuterated crystalline adamantane-d(16) (A-d(16)) and in glassy polystyrene-d(8) (PS) for various guest concentrations and coupling times tau/tau(c). For pure A-h(16) crystals spin clusters of more than 1000 connected spins were observed. We observed the evolution of the multiple quantum connectivities as a function of the coupling time. In all cases the growth curves of the; multiple quantum orders can be described by a master curve, showing the validity of a scaling law. For the diluted systems the master curve is obtained by multiplying the time axis with the square root of the dipolar line width (Delta nu)(1/2). The different local structure of the systems leads to characteristic growth curves, in particular to a quadratic function for the crystalline and to a linear function for the glassy material. For short coupling times these differences can be attributed to geometrical constraints caused by the polymer chains while for longer coupling times geometrical constraints and dynamics of the polymer chains can both be responsible for the different growth curves. The technique was applied to study slow phase separation processes in a solution of A-h(16) in PS.

Item Type: Article
Erschienen: 1997
Creators: Buntkowsky, G. and Roessler, E. and Taupitz, M. and Vieth, H. M.
Title: Adamantane as a probe for studies of spin clustering with multiple quantum NMR
Language: German
Abstract:

Time domain H-1 multiple quantum NMR (MQ NMR) was applied to study binary guest/host systems. We investigated protonated adamantane-h(16) (A-h(16)) molecules in deuterated crystalline adamantane-d(16) (A-d(16)) and in glassy polystyrene-d(8) (PS) for various guest concentrations and coupling times tau/tau(c). For pure A-h(16) crystals spin clusters of more than 1000 connected spins were observed. We observed the evolution of the multiple quantum connectivities as a function of the coupling time. In all cases the growth curves of the; multiple quantum orders can be described by a master curve, showing the validity of a scaling law. For the diluted systems the master curve is obtained by multiplying the time axis with the square root of the dipolar line width (Delta nu)(1/2). The different local structure of the systems leads to characteristic growth curves, in particular to a quadratic function for the crystalline and to a linear function for the glassy material. For short coupling times these differences can be attributed to geometrical constraints caused by the polymer chains while for longer coupling times geometrical constraints and dynamics of the polymer chains can both be responsible for the different growth curves. The technique was applied to study slow phase separation processes in a solution of A-h(16) in PS.

Journal or Publication Title: Journal of Physical Chemistry A
Volume: 101
Number: 1
Uncontrolled Keywords: nuclear-magnetic-resonance solid-state nmr dynamics decomposition spectroscopy relaxation scattering excitation simulation c10h16
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:38
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
Additional Information:

Wl080 Times Cited:13 Cited References Count:34

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