| Texto completo | |
| Autor(es): |
de Souza, Mateus S.
;
Reis, Samira G.
;
Stinghen, Danilo
;
Escobar, Livia B. L.
;
Cassaro, Rafael A. . Allao
;
Poneti, Giordano
;
Bortolot, Carolina S.
;
Marbey, Jonathan
;
Hill, Stephen
;
Vaz, Maria G. F.
Número total de Autores: 10
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Inorganic Chemistry; v. 61, n. 31, p. 11-pg., 2022-07-25. |
| Resumo | |
Using the 1- (m-tolyl)-1H-1,2,3-triazole-4-(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) (TlTrzNIT) radical and metal beta-diketonate complexes [M-(hfac)(2)(H2O)(2)], where hfac is hexafluoroacetylacetonato, three new 2p-3d heterospin complexes were synthesized. Their structures were solved using single crystal X-ray diffraction data, and magnetic investigation was performed by DC and AC measurements and multifrequency EPR spectroscopy. Compounds 1 and 2 are isostructural complexes with molecular formula [M-3(TlTrzNIT)(2)(hfac)(6)] (M-II = Mn or Cu) while compound 3 is the mononuclear [Co (TlTrzNIT)(hfac)(2)] complex. In all complexes, the radical acts as a bidentate ligand through the oxygen atom of the nitroxide moiety and the nitrogen atom from the triazole group. Furthermore, in compounds 1 and 2, the TlTrzNIT is bridge-coordinated between two metal centers, leading to the formation of trinuclear complexes. The fitting of the static magnetic behavior reveals antiferromagnetic and ferromagnetic intramolecular interactions for complexes 1 and 2, respectively. The EPR spectra of 1 are well described by an isolated ferrimagnetic S = 13/2 (= 5/2 - 1/2 + 5/2 - 1/2 + 5/2) ground state with a biaxial zero-field splitting (ZFS) interaction characterized, respectively, by 2nd order axial and rhombic parameters, D and E, such that E/D is close to the maximum of 0.33. Meanwhile, EPR spectra for 2 are explained in terms of a ferromagnetic model with weakly anisotropic Cu-radical exchange interactions, giving rise to an isolated S = 5/2 (= 5 x 1/2 ) ground state with both an anisotropic g tensor and a weak ZFS interaction. Complex 2 represents one of only a few examples of Cu-radical moieties with measurable exchange anisotropy. (AU) | |
| Processo FAPESP: | 09/54082-2 - EMU: projeto para aquisição de um magnetômetro de amostra vibrante que utiliza como sensor um dispositivo supercondutor de interferência quântica acoplado (Squid-VSM) com circuito fechado de criogenia |
| Beneficiário: | Ernesto Chaves Pereira de Souza |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa Equipamentos Multiusuários |