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Odd‐Even Effect on Luminescence Properties of Europium Aliphatic Dicarboxylate Complexes
Author(s) -
Assunção Israel P.,
Carneiro Neto Albano N.,
Moura Renaldo T.,
Pedroso Cássio C. S.,
Silva Ivan G. N.,
Felinto Maria C. F. C.,
Teotonio Ercules E. S.,
Malta Oscar L.,
Brito Hermi F.
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900603
Subject(s) - luminescence , ligand (biochemistry) , chemistry , coordination sphere , lanthanide , quantum yield , crystallography , quenching (fluorescence) , europium , monoclinic crystal system , molecule , zigzag , crystal structure , materials science , fluorescence , ion , geometry , organic chemistry , physics , biochemistry , receptor , optoelectronics , mathematics , quantum mechanics
The odd–even effect in luminescent [Eu 2 (L) 3 (H 2 O) x ]⋅y(H 2 O) complexes with aliphatic dicarboxylate ligands (L: OXA, MAL, SUC, GLU, ADP, PIM, SUB, AZL, SEB, UND, and DOD, where x=2–6 and y=0–4), prepared by the precipitation method, was observed for the first time in lanthanide compounds. The final dehydration temperatures of the Eu 3+ complexes show a zigzag pattern as a function of the carbon chain length of the dicarboxylate ligands, leading to the so‐called odd‐even effect. The FTIR data confirm the ligand–metal coordination via the mixed mode of bridge–chelate coordination, except for the Eu 3+ ‐oxalate complex. XRD results indicate that the highly crystalline materials belong to the monoclinic system. The odd–even effect on the 4 f–4 f luminescence intensity parameters (Ω 2 and Ω 4 ) is explained by using an extension of the dynamic coupling mechanism, herein named the ghost‐atom model. In this method, the long‐range polarizabilities ( α * ) were simulated by a ghost atom located at the middle of each ligand chain. The values ofα * were estimated using the localized molecular orbital approach. The emission intrinsic quantum yield ( Q L n L n ) of the Eu 3+ complexes also presented an the odd‐even effect, successfully explained in terms of the zigzag behavior shown by the Ω 2 and Ω 4 intensity parameters. Luminescence quenching due to water molecules in the first coordination sphere is also discussed and rationalized.