abstract
A series of nine tetrakis lanthanide beta-diketonate complexes of the type [C(2)mim][Ln(fod)(4)] (C(2)mim = 1-ethyl-3-methylimidazolium, fod = 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate) were prepared, with yields above 80%, and their thermochemical, photophysical and magnetic susceptibilities were evaluated. Thermochemical studies presented a rare and reversible conversion between two solid phases (polymorphism), characteristic of the [Ln(fod)(4)](-) anion. Photophysical and magnetic studies revealed that Dy and Er presented the multifunctionality of being simultaneously SMMs and visible (Dy) or near infra-red (Er) emitters. The Nd, Ho and Tm analogues present characteristic emission bands in the NIR region (800-1200 nm), while Sm, Eu, Tb and Dy present emissions in the visible range. Magnetic susceptibility of Tb, Dy, Ho, Er and Tm salts were measured in the temperature range of 2-300 K, showing paramagnetic behaviour, although with different regimes, with AC susceptibility measurements, at different frequencies in the range of 10-10 000 Hz, providing evidence of slow magnetic relaxation processes for Gd, Dy and Er analogues with SMM behavior.
keywords
SINGLE-ION MAGNETS; CRYSTAL-STRUCTURES; SLOW RELAXATION; COMPLEXES; ANISOTROPY; LIQUID
subject category
Chemistry
authors
Cerdeira, AC; Leal, JP; Avo, J; Viola, C; Casimiro, MH; Ferreira, LM; Paz, FAA; Pereira, LCJ; Pereira, CCL; Monteiro, B
our authors
Filipe Alexandre Almeida Paz
Principal Researcheracknowledgements
This research was funded by FCT -Fundaca~o para a Cie<^>ncia e a Tecnologia, I. P. through the National Infrastructure Roadmap, LTHMFL-NECL, LISBOA-01-0145-FEDER-022096 and contract UID/Multi/04349/2019 (L. C. J. P.; A. C. C.), grants UIDB/00100/2020 (J. P. L. and B. M.), BL156/2019_IST-ID (A. C. C.), contract no. IST-ID/077/2018 (B. M.), Norma transito ' ria DL 57/2016 Program Contract (C. C. L. P). SFRH/BPD/120599/2016 (J. A.) and PTDC/QUI-QFI/32007/2017 (J. A.). This work was funded by the Associated Laboratory for Sustainable Chemistry-Clean Processes and Technologies-LAQV, which is financed by the National funds from FCT/MEC grant UID/QUI/50006/2019 (C. C. L. P) and co-financed by the ERDF under the PT2020 Partnership Agreement project POCI-01-0145-FEDER -007265 (C. C. L. P). This research was funded by FCT -Fundaca~o para a Cie<^>ncia e a Tecnologia, I. P. under grants SFRH/BPD/120599/2016 and PTDC/QUI-QFI/32007/2017. Centro de Qui ' mica Estrutural (CQE) and Institute of Molecular Sciences (IMS) acknowledge the financial support of Fundaca~o para a Cie<^>ncia e Tecnologia through Projects UIDB/00100/2020, UIDP/00100/2020, and LA/P/0056/2020, respectively.