A Study of translational diffusion constants of paramagnetic species in solution

(1993) A Study of translational diffusion constants of paramagnetic species in solution. Masters thesis, King Fahd University of Petroleum and Minerals.


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The translation diffusion constants of two paramagnetic species, dichlorobis (n-cyclopentadienyl) vanadium, abbreviated as (Cp₂VC1₂) in chloroform, and S-methyl-N-5-methoxy-salicylidenehydrazine-carbodithioatophenanthroline- oxovnadium (IV), abbreviated as VO[5-MeO-Sal SB] (Phen) in methylene chloride were measured at room temperature (25+1⁰C) by a capillary diffusion method. The translational diffusion processes were monitored by electron spin resonance spectral intensities as a function of time. The total spectral intensities were plotted as a function of time and from the best least squares fit a single value of the translational diffusion coefficient was obtained. A computer program based on Fick's second law of diffusion for the capillary diffusion cell has been written to get a single value of the diffusion constant. Using Stokes Einstein for translational diffusion, the hydrodynamic radii and the molecular hydrodynamic volumes of the two paramagnetic species in solution were found to be 0.520 x 10⁻⁵ and 0.655 x 10⁻⁵ cm²/s, and 250 and 275 A³, respectively. In addition, the rotational correlation times as a function of temperature were determined from the line width data. The anisotropic interaction parameter k determined from the plot of t₁ vs n/T was found to be 0.150. The anisotropic interaction parameter is a measure of the anisotropy of intermolecular interactions. The values show that Cp₂ VC1₂ in toluene is more slip than VOAA in toluene which is more stick and its k is 0.53. The stickiness factor (S) is calculated to be 0.0875 for Cp₂ VC1₂ which is close to the slip limit (S=0). Therefore, it seems that k value decreases with decreasing solute corrugation.

Item Type: Thesis (Masters)
Subjects: Chemistry
Department: College of Chemicals and Materials > Chemistry
Committee Advisor: Hwang, Jimmy S.
Committee Members: Klein, Uwe Karl Albert and Lyle, Samuel J.
Depositing User: Mr. Admin Admin
Date Deposited: 22 Jun 2008 13:48
Last Modified: 01 Nov 2019 13:51
URI: https://eprints.kfupm.edu.sa/id/eprint/9782