New Mononuclear And Binuclear Lanthanide Complexes With Slow Magnetic Relaxation Behavior

This work focuses on the attractive research fields of molecular magnetism and single-molecule magnets. Choosing the nitrogen-containing ligands and nitronyl nitroxide radicals ligands to coordinate with lanthanide ions, twenty six mononuclear and binuclear lanthanide complexes have been obtained. They have been characterized by X-ray single crystal structure analysis, elemental analyses, IR spectra, electronic spectra, fluorescence spectra and magnetic measurements. Main contents are as following:1. Four series of binuclear lanthanide complexes have been synthesized by using the different nitrogen-containing ligands of2,2’-bipyrimidine (bpm),1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene (2-bpdb),1,4-bis(2-pyridyl)-2,3-diaza-1,3-butadiene (4-bpdb) and N-(2-pyridylmethyl)-3-methoxy-salicylaldiminato (Hvalampy). The magnetic measurements show that the Dy2complex1and3exhibit slow magnetic relaxation and the effective energy barrier of37.2K and150.33K, respectively.2. A series of mononuclear lanthanide complexes have been synthesized through the reaction of nitrogen-containing ligand (4-bpdb) and lanthanide ions. The Eu(Ⅲ) complex6and Tb(Ⅲ)8exhibit the characteristic fluorescence spectra of the lanthanide ions. The magnetic measurements show that the Dy(Ⅲ) complex9exhibits slow magnetic relaxation and the effective energy barrier of23.01K.3. A series of four-spin binuclear lanthanide-radical complexes have been synthesized by using3-pyridyl-3-phenyl substituted nitronyl nitroxide radical (NIT3Ph3Py). The magnetic studies show the dominating ferromagnetic interaction between the lanthanide ions and nitroxide radicals within the complexes. The magnetic measurements also show that the Dy(Ⅲ) complex23exhibits slow magnetic relaxation with the effective energy barrier of3.12K.4. Three series of tri-spin mononuclear lanthanide-radical complexes have been synthesized by using2-isopropyl-phenyl, n-butyl and5-methylimidazole substituted nitronyl nitroxide radicals (NITPhiPr, NITnBu, NITMelm). The approximation model is used to analysis the magnetic data of lanthanide ions with spin-orbit coupling to obtain a reasonable result.