Slow magnetic relaxation in two-dimensional 3d-4f complexes based on phenyl pyrimidyl substituted nitronyl nitroxide radicals.
Three isostructural two-dimensional 2p-3d-4f complexes, namely, {Tb(hfac)3[Cu(hfac)2]3(NITPhPyrim)2}·2CH2Cl2 and 1 {Ln(hfac)3[Cu(hfac)2]3(NITPhPyrim)2} (Ln(III) = Ho 2, Yb 3; hfac = hexafluoroacetylacetonate; NITPhPyrim = 2-[4-(5-pyrimidyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were characterized in terms of structure and magnetism. These heterospin compounds possess a two-dimensional sheet structure involving Cu(II) and Ln(III) ions bridged by NITPhPyrim radicals through their NO groups and pyrimidine rings. DC magnetic studies show that these complexes exhibit ferromagnetic exchange coupling between radical ligands and metal atoms. AC measurements of the Tb complex reveal slow relaxation of the magnetization. Interestingly, the Tb complex displays two field-induced relaxation processes.
Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry and Tianjin Key Laboratory of Metal and Molecule-based Material Chemistry, Nankai University, Tianjin 300071, China. llicun@nankai.edu.cn.
Mei
M
Zhu
Juanjuan
J
Wang
Meng
M
Yang
Yue
Y
Ma
Licun
L
Li