Odd-Even Effect on Luminescence Properties of Europium Aliphatic Dicarboxylate Complexes
authors Assuncao, IP; Neto, ANC; Moura, RT; Pedroso, CCS; Silva, IGN; Felinto, MCFC; Teotonio, EES; Malta, OL; Brito, HF
nationality International
journal CHEMPHYSCHEM
author keywords dicarboxylate complexes; europium; luminescence; odd-even effect; photoluminescence intensity parameters
keywords METAL-ORGANIC FRAMEWORKS; INTRAMOLECULAR ENERGY-TRANSFER; SELF-ASSEMBLED MONOLAYERS; SPECTROSCOPIC PROPERTIES; INTENSITY PARAMETERS; 4F-4F TRANSITIONS; CHEMICAL-BOND; CARBOXYLATES; ALTERNATION; COVALENCY
abstract The odd-even effect in luminescent [Eu-2(L)(3)(H2O)(x)].y(H2O) 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 Eu3+ 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 Eu3+-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 (omega(2) and omega(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 (alpha*) were simulated by a ghost atom located at the middle of each ligand chain. The values of alpha* were estimated using the localized molecular orbital approach. The emission intrinsic quantum yield (QLnLn) of the Eu3+ complexes also presented an the odd-even effect, successfully explained in terms of the zigzag behavior shown by the omega(2) and omega(4) intensity parameters. Luminescence quenching due to water molecules in the first coordination sphere is also discussed and rationalized.
publisher WILEY-V C H VERLAG GMBH
issn 1439-4235
year published 2019
volume 20
issue 15
beginning page 1931
ending page 1940
digital object identifier (doi) 10.1002/cphc.201900603
web of science category Chemistry, Physical; Physics, Atomic, Molecular & Chemical
subject category Chemistry; Physics
unique article identifier WOS:000474699900001
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journal impact factor 2.947
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