2025/02/18 by Joan Torrent, Cristina Puigjaner, Radovan Herchel +1 · 1 voice
Materials Science · Chemistry · #Magnetism in coordination complexes #Lanthanide and Transition Metal Complexes #Metal-Organic Frameworks: Synthesis and Applications
paper · pdf · doi:10.1021/acs.inorgchem.4c04542
openalex publication_date 2025/02/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
The reaction between two equivalents of the Schiff base ligands N, N ′-bis(3-methoxysalicylidene)ethylenediamine (H 2 L1) or enantiopure N, N ′-bis(3-methoxysalicylidene)cyclohexane-1,2-diamine (H 2 L2) with one equivalent of Ce(NO 3 ) 3 ·6H 2 O in the presence of a bulky counteranion leads to the formation of chiral metal–organic frameworks (MOFs) whose channels encapsulate the counteranion, leading to the formation of compounds with the structural formulas [Ce(NO 3 ) 2 (L1) 2 ]X·H 2 O n, where X = ClO 4 – ( 1 ), PF 6 – ( 2 ), or BF 4 – ( 3 ), and [Ce(NO 3 ) 2 (L2) 2 ]X·CH 3 CN n, where X = ClO 4 – ( 4 ), PF 6 – ( 5 ), or BF 4 – ( 6 ), as well as the isostructural reference compound Nd(NO 3 ) 2 (L1) 2 ]BF 4 ·CH 3 CN n ( 3Nd ). A combination of static and dynamic magnetic measurements demonstrates the good isolation of the Ce III centers and a field-induced slow relaxation of the magnetization. Correlations between the temperature and field-dependent magnetic relaxation data and ultralow-frequency Raman spectroscopy reveal the presence of a vibronic barrier driving magnetic relaxation. Theoretical calculations have been performed to elucidate the nonparticipation of the electronic excited states in the main relaxation processes.