Pulsed NMR study of molecular motions and phase transitions in [N(CH3)4]PbX3 (X=Cl, Br, I)

Vijayaraghavan, D and Ramakrishna, J (1993) Pulsed NMR study of molecular motions and phase transitions in [N(CH3)4]PbX3 (X=Cl, Br, I). In: Spectrochimica Acta Part A: Molecular Spectroscopy, 49 (8). pp. 1121-1129.

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Abstract

Proton spin—lattice relaxation time (T1) is measured in [N(CH3)4]PbX3 (X=Cl, Br, I) from 300-77 K at 9.75 MHz. All the compounds show discontinuous changes in T1 values (at 256, 270 and 277 K, respectively), indicating phase transitions. Single T1 minimum is observed in all the cases and the T1 variation is explained in terms of [N(CH3)4] and CH3 group dynamics. The activation energy Eα decreases from chloride to iodide (from 4 to 2 kcal/mol). In bromide and iodide, T1 is found to decrease with increase in temperature at higher temperatures, indicating the presence of spin—rotation interaction.

Item Type:	Journal Article
Publication:	Spectrochimica Acta Part A: Molecular Spectroscopy
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	24 Feb 2011 05:41
Last Modified:	24 Feb 2011 05:41
URI:	http://eprints.iisc.ac.in/id/eprint/35714

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