| Autor: |
Kalinke LHG; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain.; Instituto Federal de Goiás , 75131-457 , Anápolis , Goiás Brazil.; Instituto de Química , Universidade Federal de Goiás , 74690-900 , Goiânia , Goiás Brazil., Cangussu D; Instituto de Química , Universidade Federal de Goiás , 74690-900 , Goiânia , Goiás Brazil., Mon M; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain., Bruno R; Dipartimento di Chimica e Tecnologie Chimiche , Università della Calabria , Rende 87036 , Cosenza , Italy., Tiburcio E; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain., Lloret F; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain., Armentano D; Dipartimento di Chimica e Tecnologie Chimiche , Università della Calabria , Rende 87036 , Cosenza , Italy., Pardo E; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain., Ferrando-Soria J; Departament de Química Inorgànica, Instituto de Ciencia Molecular , Universitat de València , 46980 Paterna , València , Spain. |
| Abstrakt: |
Achieving fine control on the structure of metal-organic frameworks (MOFs) is mandatory to obtain target physical properties. Herein, we present how the combination of a metalloligand approach and a postsynthetic method is a suitable and highly useful synthetic strategy to success on this extremely difficult task. First, a novel oxamato-based tetranuclear cobalt(III) compound with a tetrahedron-shaped geometry is used, for the first time, as the metalloligand toward calcium(II) metal ions to lead to a diamagnetic Ca II -Co III three-dimensional (3D) MOF ( 1 ). In a second stage, in a single-crystal-to-single-crystal manner, the calcium(II) ions are replaced by terbium(III), dysprosium(III), holmium(III), and erbium(III) ions to yield four isostructural novel Ln III -Co III [Ln = Tb ( 2 ), Dy ( 3 ), Ho ( 4 ), and Er ( 5 )] 3D MOFs. Direct-current magnetic properties for 2 - 5 show typical performances for the ground-state terms of the lanthanoid cations [ 7 F 6 (Tb III ), 6 H 15/2 (Dy III ), 5 I 8 (Ho III ), and 4 I 15/2 (Er III )]. Analysis of the χ M T data indicates that the ground state is the lowest M J value, that is, M J = 0 ( 2 and 4 ) and ± 1 / 2 ( 3 and 5 ). Kramers' ions ( 3 and 5 ) exhibit field-induced emergent frequency-dependent alternating-current magnetic susceptibility signals, which is indicative of the presence of slow magnetic relaxation typical of single-molecule magnets. |
