PUBLICATION: DALTON TRANSACTIONS

AUTHORS: Li, YJ; Chen, XT; Gong, Y

 

Although luminescent lanthanide-containing molecular complexes are well-known, it is not the case for La3+ with no 4f or 5d electrons, and the few luminescent complexes of La3+ contain luminescent ligands. Herein, we report an unexpected photoluminescence phenomenon of the LaI3(THF)(4) complex that was easily prepared by immersing commercial anhydrous LaI3 in THF. Strong blue emission was observed when LaI3(THF)(4) was subjected to UV irradiation at 254 nm, which contrasts the non-luminescence character of either LaI3 or THF. The absolute emission quantum yield was determined to be 50.5%. The observed luminescence of LaI3(THF)(4) results from metal-to-ligand charge transition (MLCT) which differs from the known charge transition types for lanthanum complexes according to DFT/TDDFT calculations. The photoluminescence of LaI3 can be switched on and off by reversible THF association and dissociation. THF concentrations as low as 0.1 vol% in n-hexane and 0.5 vol% in the gas phase can be detected, indicating the capability of anhydrous LaI3 as a sensor for convenient and rapid THF detection.

 

LINKS: http://dx.doi.org/10.1039/d1dt00162k