EPR Spectra of Gadolinium Complexes with Asn Schiff Bases

EPR spectra of two new gadolinium complexes with amino Schiff bases in polycrystalline powder and in three organic solvents were investigated at different temperatures.EPR character of AS gedolinium complex in DMSO at variable temperatures were measured.It is found that an decrease of the line widths and an increase of crossing relaxation time with the decrease of temperature is caused by the spin-lattice interaction.
The freezing EPR spectra of two complexes in various solvents at low temperature present the features of the U spectrum.The results show that the crystal field strength is different to same complex in various solvents:DMSO＞DMF＞CH₃OH,this is due to the solvent effect,we considered that the principal factor may be the dielectric constant of the solvents;besides,the crystal field strength is also different to various complexes in same solvent:complex 1＞complex 2. The EPR spectra of two complexes in various solvents at room temperature exhibit the isotropic character.The relative relationship of the same complex in different solvents is ΔH_pp（DMSO）＞ΔH_{pp（CH3OH）}＞ΔH_pp（DMF）.The crystalline powder EPR spectra of two complexes at different temperature show the wider single peak.The spectral line shapes at low temperature are similar to those of samples at room temperature.Changes in spectral parameters g are not clear,but the line widths were broadened with the decrease of temperautre.