Temperature Effect on Molecular Dynamics in Micellar System. Proton Spin-Lattice Relaxation Study of Cetyltrimethylammmonium Bromide in Water-Dimethylsulfoxide Mixtures

AbstractThe proton spin-lattice relaxation time T1 (at 5.4, 10 and 15 MHz) and second moment M2 (at 9.8 MHz) have been measured in hydrazinium Perchlorate (N2H5ClO4). The temperature dependence of T, shows two minima. The low temperature T, minimum has been explained in terms of NH3 reorientation about the N-N axis while the high temperature minimum is attributed to the exchange of protons within the NH2 group (180° flip about the H - N - H bisectrix). The activation energies for NH3 and NH: motions are found to be 20.5 kJ mol-1 and 39.8 kJ mol-1 , respectively. The second moment variation with temperature shows two transitions around 120 K and 210 K and has been discussed in terms of NH3/NH2 motions.

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Proton spin–lattice relaxation study of the hydration of self-stressed expansive cement

Cement and Concrete Research ◽

10.1016/s0008-8846(00)00460-9 ◽

2001 ◽

Vol 31 (2) ◽

pp. 263-269 ◽

Cited By ~ 16

Author(s):

T Apih ◽

G Lahajnar ◽

A Sepe ◽

R Blinc ◽

F Milia ◽

...

Keyword(s):

Lattice Relaxation ◽

Proton Spin ◽

Spin Lattice Relaxation ◽

Spin Lattice ◽

Relaxation Study ◽

Expansive Cement

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Proton spin-lattice relaxation study of the phase transition in TlH2AsO4

Solid State Communications ◽

10.1016/0038-1098(78)91023-2 ◽

1978 ◽

Vol 27 (10) ◽

pp. 999-1001 ◽

Cited By ~ 18

Author(s):

R. Blinc ◽

M. Rožmarin ◽

F. Milia ◽

M. Melisaropoulou

Keyword(s):

Phase Transition ◽

Lattice Relaxation ◽

Proton Spin ◽

Spin Lattice Relaxation ◽

Spin Lattice ◽

Relaxation Study

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A proton relaxation study of the conformations of some purine mononucleotides in aqueous solution

Canadian Journal of Chemistry ◽

10.1139/v82-426 ◽

1982 ◽

Vol 60 (23) ◽

pp. 2976-2983 ◽

Cited By ~ 4

Author(s):

C. F. G. C. Geraldes ◽

H. Santos ◽

A. V. Xavier

Keyword(s):

Relaxation Times ◽

Lattice Relaxation ◽

Proton Spin ◽

Spin Lattice Relaxation ◽

Proton Relaxation ◽

Spin Lattice ◽

Population Distributions ◽

Anti Conformation ◽

Relaxation Study ◽

Interproton Distances

A method is described by which conformationally averaged interproton distances in mononucleotides are obtained from measured proton spin-lattice relaxation times and published crystal coordinates of selected mononucleotides. The glycosil conformations of adenosine in D2O and DMSO-d6 and of 5′-AMP, 5′-GMP, 3′-AMP, and 2′-AMP in D2O are examined by quantitative analysis of the conformationally averaged interproton distances in terms of population distributions obtained from potential energy calculations. 5′-AMP strongly prefers a single glycosyl conformation in the anti range. Besides the anti conformation, 5′-GMP has a secondary minimum in the syn region. 3′-AMP, 2′-AMP, and adenosine have more latitude in their glycosyl torsion angle values, with both the syn and anti regions highly populated.

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