טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentZakrassov Alexander
SubjectMolecular-Based Magnetic Materials
DepartmentDepartment of Chemistry
Supervisors Professor Emeritus Menahem Kaftory
Professor Amit Keren


Abstract

This work examines the correlation between the crystal structures and the magnetic properties of stable organic radicals and organometallic compounds as well as dielectric properties of the organometallic compounds.

The hybrid density functional/Hartree-Fock methods (DF/HF) UB3LYP and UB1LYP with 6-31 G(d) basis set have been applied to calculate the atomic spin densities and isotropic hyperfine coupling constants (hfcc's) calculations of the NS, ONS, NN and NO bridged radicals. The calculated hfcc's are in a good agreement with the experimental values.

Nitrogen isotropic hfcc's in different nitroxide radicals calculated via hybrid density functional/Hartree-Fock methods (UB3LYP and UB1LYP) with-31G(d) basis set were found to be in a good agreement with the experimental EPR results.

The crystal structures, DFT calculations and magnetic properties of several nitronyl nitroxide radicals are reported.

DFT calculations, EPR spectra and magnetic properties of the halogen- and cyano-substituted nitronyl nitroxide radicals are reported. The magnetic measurements show that these compounds exhibit large magnetic coupling.

The crystal structures of copper and iron complexes as well as dielectric and magnetic properties are reported. The studied samples show a linear dielectric behavior characterized by a high dielectric permittivity. The ionic-bonds show characteristic dielectric resonance in the range of few kHz. The high dielectric permittivity and low ac conductivity make these materials attractive for high-k dielectric applications. The reported compounds may be good candidates for crystal engineering towards multifunctional molecular nanomaterials exhibiting both excellent dielectric and magnetic properties.