Nitronyl nitroxide biradical-supported lanthanide hetero-spin compounds: Magnetic relaxation in Dy analogue
作者:Hongdao Li、Jing Xie、Lu Xi、Lijun Zhai、Yulan Niu
DOI:10.1016/j.ica.2019.119188
日期:2020.1
Based on nitronyl nitroxide biradical ligand (NITPhBrbis), two lanthanide coordination polymers, namely, [Ln(hfac)(3)(NITPhBrbis)](2)center dot C7H(16) (Ln(III) = Gd 1, Dy 2; hfac = hexafiuoroacetylacetonate; NITPhBrbis = 1-bromo-3,5-bis(1'-oxyl-3'-oxido-4',4',5',5'-tetrarnethyl-4,5-hydro-1H-imidazol-2-yl)-benzene) have been isolated and characterized. Both compounds exhibit 2p-4f tri-spin mononuclear structure, in which NITPhBrbis molecule acts as a bidentate ligand with one coordinated lanthanide ion. DC magnetic susceptibility measurements, performed on Gd compound, reveal the presence of ferromagnetic coupling between Ge-III center and the coordinated NO group, with J(1) = 1.13 cm(-1) following spin Hamiltonian (H) over cap = -2J(1)((S) over cap (Gd). (S) over cap (Rad1) + (S) over cap (Gd). (S) over cap (Rad2)) - 2J(2) (S) over cap (Rad1).(S) over cap (Rad2). Moreover, Dy (2) complex presents slow magnetic relaxation process as confirmed by ac-susceptibility measurement.