Coumarin-lanthanide based compounds with SMM behavior and high quantum yield luminescence
Por:
Arauzo, A., Gasque, L., Fuertes, S., Tenorio, C., Bernes, S., Bartolome, E.
Publicada:
21 oct 2020
Categoría:
Inorganic chemistry
Resumen:
Coumarin-based lanthanide complexes of general formula
(Ln(coum)(3)(phen)(H2Ox]center dot yH(2)O (Ln-phen, x = 0,1, 0 <= y <=
1.5: phen = 1,10-phenanthroline; coum = 3-acetyl-4-hydroxylato-coumarin;
Ln = Eu,Tb, Dy, Tm) and (Ln(coum)(3)(batho)]]center dot 0.7EtOH
(Ln-batho, batho = 4,7-diphenyl-1,10-phenanthroline; Ln = Eu, Tb, Dy,
Tm) were synthesized. The magnetic relaxation and photoluminescence
behavior of these complexes was compared with that of the related
compounds (Ln(coum)(3)(EyOH)](H2O)]center dot EtOH (Ln-coum), so as to
investigate the effects of incorporating a second chromophore, either
the phen or batho ligand, to the original coordination scaffold,
provided with three coumarin (coum) ligands. Slow relaxation of the
magnetization under H = 0 with moderate activation energies was observed
for the Dy-phen (U/k(B) = 99.1 K) and Dy-batho (U/k(B) = 67.1 K)
compounds, whereas Tb analogues presented field-induced single molecule
magnet (SMM) behavior, with U/k(B) = 11.7 K (16.6 K@3 kOe) for Tb-phen
(Tb-batho), respectively. Luminescent emission in the visible range was
observed for all the Ln-coumarin based compounds upon ligand
sensitization, with high quantum yields of 45 (40%) for Eu-phen
(Eu-batho) compounds and 65-76-58% for Tb-coum, phen, batho analogues.
Sensitization is mainly provided by the coumarin ligand having the
energy difference Delta E between its triplet state Ti and the
lanthanide emitting level closest to the optimum, while the second
ligand can play either a synergistic or competing sensitizing role. The
Tb-phen/batho compounds presented simultaneously SMM and luminescent
behavior, with excellent values of the bifunctional figure of merit
(eta(SMM-QY) similar to 1000% K). The reported compounds represent a
new class of bifunctional materials with potential interesting
application in various fields.
Filiaciones:
Arauzo, A.:
Univ Zaragoza, Serv Medidas Fis, Pedro Cerbuna 12, Zaragoza 50009, Spain
Univ Zaragoza, CSIC, Inst Nanociencia & Mat Aragon INMA, Zaragoza, Spain
Gasque, L.:
(Corresponding Author), Univ Nacl Autonoma Mexico, Fac Quim, Ave Univ 3000, Cdmx 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, Ave Univ 3000, Cdmx 04510, Mexico
Fuertes, S.:
Univ Zaragoza, CSIC, Inst Sintesis Quim & Catalisis Homogenea, Pedro Cerbuna 12, Zaragoza 50009, Spain
Tenorio, C.:
Univ Nacl Autonoma Mexico, Fac Quim, Ave Univ 3000, Cdmx 04510, Mexico
Bernes, S.:
BUAP, Inst Fis Luis Rivera Terrazas, Edificio IF2,Lab 103-104, Puebla 72570, Mexico
Bartolome, E.:
(Corresponding Author), Escola Univ Salesiana Sarria EUSS, Passeig St Joan Bosco 74, Barcelona 08017, Spain
Escola Univ Salesiana Sarria EUSS, Passeig St Joan Bosco 74, Barcelona 08017, Spain
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