Pereira Laura C J, Camp Clément, Coutinho Joana T, Chatelain Lucile, Maldivi Pascale, Almeida Manuel, Mazzanti Marinella
C2TN, Instituto Superior Técnico, Universidade de Lisboa/CFMCUL , Estrada Nacional 10, 2695-066 Bobadela LRS, Portugal.
Inorg Chem. 2014 Nov 17;53(22):11809-11. doi: 10.1021/ic501520c. Epub 2014 Oct 29.
The magnetic properties of the two uranium coordination compounds, [K(18c6)][U(OSi(O(t)Bu)3)4] and [K(18c6)][U(N(SiMe3)2)4], both presenting the U(III) ion in similar pseudotetrahedral coordination environments but with different O- or N-donor ligands, have been measured. The static magnetic susceptibility measurements and density functional theory studies suggest the presence of different ligand fields in the two compounds. Alternating-current susceptibility studies conducted at frequencies ranging from 95 to 9995 Hz and at temperatures in the 1.7-10 K range revealed for both compounds slow magnetic relaxation already at zero static magnetic field with similar energy barriers U ∼24 K.
已对两种铀配位化合物[K(18c6)][U(OSi(O(t)Bu)3)4]和[K(18c6)][U(N(SiMe3)2)4]的磁性进行了测量，这两种化合物中的U(III)离子均处于相似的伪四面体配位环境中，但具有不同的O供体或N供体配体。静态磁化率测量和密度泛函理论研究表明，这两种化合物中存在不同的配体场。在95至9995 Hz的频率范围内以及1.7至10 K的温度范围内进行的交流磁化率研究表明，这两种化合物在零静态磁场下就已经出现了缓慢的磁弛豫，且具有相似的能垒U ∼24 K。
