Investigation of slow magnetic relaxation in a series of 1D polymeric cyclobutane-1,1-dicarboxylates based on LnV units (Ln = Tb, Dy, Ho, Er, Tm, Yb): rare examples of V-4f single-molecule magnets

• Published in: Dalton transactions : an international journal of inorganic chemistry 2024-11, Vol.53 (45), p.18161-18174
• Main Authors: Bazhina, Evgeniya S, Shmelev, Maxim A, Gogoleva, Natalia V, Babeshkin, Konstantin A, Kurganskii, Ivan V, Efimov, Nikolay N, Fedin, Matvey V, Kiskin, Mikhail A, Eremenko, Igor L
• Format: Article
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d4dt01779j

The reactions of VOSO 4 ·3H 2 O with Na 2 (cbdc) (cbdc 2− - dianion of cyclobutane-1,1-dicarboxylic acid) and lanthanide( iii ) nitrates taken in a molar ratio of 1 : 2 : 1 were found to yield a series of isostructural heterometallic compounds [NaLn(VO) 2 (cbdc) 4 (H 2 O) 10 ] n ( 1 Ln , Ln = Tb, Dy, Ho, Er, Tm, Yb). These compounds are constructed from trinuclear anionic units [Ln(VO) 2 (cbdc) 4 (H 2 O) 8 ] − ({LnV 2 } − ) linked by Na + ions into 1D polymeric chains. The crystal structures of 1 Dy and 1 Er were determined by single-crystal X-ray diffraction (XRD), and their isostructurality with 1 Tb , 1 Ho , 1 Tm , and 1 Yb was proved by powder X-ray diffraction (PXRD). According to alternating current (ac) magnetic susceptibility measurements, 1 Dy , 1 Er , and 1 Yb exhibited field-induced slow relaxation of magnetization. Compound 1 Er is the first representative of Er III -V IV single-molecule magnets. Measuring the temperature dependences of the phase memory time ( T m ) for 1 Dy and 1 Yb using pulsed EPR spectroscopy allowed us to observe the phenomenon of phase relaxation enhancement (PRE) at temperatures below 30 K. In future, this phenomenon may contribute to the evaluation of relaxation times of the lanthanide ions. New rare Ln III -V IV single-molecule magnets (Ln = Dy, Er, Yb) were synthesized and characterized. For Dy III -V IV and Yb III -V IV complexes studied by EPR spectroscopy, the phenomenon of phase relaxation enhancement (PRE) was observed.