Curiosities of the Electron Dynamics of Spin-Crossover Solids (Moessbauer)
Federer, Wayne Douglas
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/70271
Description
Title
Curiosities of the Electron Dynamics of Spin-Crossover Solids (Moessbauer)
Author(s)
Federer, Wayne Douglas
Issue Date
1984
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Inorganic
Abstract
Perchlorate salts of the ferric complexes of tridentate Schiff base ligands derived from salicylalaldehyde and N-(aminoalkyl)aziridines have been prepared and their spin-crossover properties in the solid state have been characterized using variable-temperature (4.2-313 K) magnetic susceptibility, EPR spectroscopy, and ('57)Fe Mossbauer spectroscopy. For the unperturbed complex "FeP" the low-spin (LS) (DBLHARR) high-spin (HS) spin state interconversion occurs rapidly at all temperatures, as compared to the lifetime of the ('57)Fe nuclear excited state, unlike that for most other N(,4)O(,2) complexes which flip spins slowly compared to the characteristic timescale of the Mossbauer technique. However the electron dynamics of FeP complexes are found to be highly sensitive to the nature of their solid state environs, depending on the degree of crystallinity or "defect character" as well as the presence of solvating CH(,2)Cl(,2) molecules or isostructural diamagnetic cobaltic complexes in the lattice. The defect character, as inferred from powder x-ray diffraction measurements, varies with the method of sample preparation or mechanical grinding of the solid. Introduction of defects slows down the spin state interconversion for at least some of the FeP complexes and causes incompleteness of the HS(--->)LS transformation at cryogenic temperatures. These perturbations of the electron dynamics are explained at a microscopic level in terms of the same nucleation and growth mechanism previously invoked to account for the unusual static properties of spin-crossover solids.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
