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Dinuclear Lanthanide(III)‐ m ‐ODO2A‐dimer Macrocyclic Complexes: Solution Speciation, DFT Calculations, Luminescence Properties, and Promoted Nitrophenyl‐Phosphate Hydrolysis Rates
Author(s) -
Chang C. Allen,
Lee HwaYu,
Lin SyueLiang,
Meng ChingNing,
Wu TsungTa
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201800037
Subject(s) - lanthanide , chemistry , dimer , phosphodiester bond , luminescence , reaction rate constant , ligand (biochemistry) , hydrolysis , ion , crystallography , stability constants of complexes , analytical chemistry (journal) , kinetics , organic chemistry , materials science , rna , biochemistry , physics , receptor , optoelectronics , quantum mechanics , gene
Potentiometric speciation studies, mass spectrometry, and DFT calculations helped to predict the various structural possibilities of the dinuclear trivalent lanthanide ion (Ln III , Ln=La, Eu, Tb, Yb, Y) complexes of a novel macrocyclic ligand, m ‐ODO2A‐dimer (H 4 L), to correlate with their luminescence properties and the promoted BNPP and HPNP phosphodiester bond hydrolysis reaction rates. The stability constants of the dinuclear Ln 2 ( m ‐ODO2A‐dimer) complexes and various hydrolytic species confirmed by mass spectrometry were determined. DFT calculations revealed that the Y 2 LH −1 and the Y 2 LH −2 species tended to form structures with the respective closed‐ and open‐form conformations. Luminescence lifetime data for the heterodimetallic TbEuL system confirmed the fluorescence resonance energy transfer from the Tb III to Eu III ion. The internuclear distance R TbEu values were estimated to be in the range of 9.4–11.3 Å (pH 6.7–10.6), which were comparable to those of the DFT calculated open‐form conformations. Multiple linear regression analysis of the k obs data was performed using the equation: k obs,corr. = k obs − k obs,OH = kLn2 LHM - > 1[Ln 2 LH −1 ]+ kLn2 LH- 2[Ln 2 LH −2 ] for the observed Ln 2 L‐promoted BNPP/HPNP hydrolysis reactions in solution pH from 7 to 10.5 (Ln=Eu, Yb). The results showed that the second‐order rate constants for the Eu 2 LH −2 and Yb 2 LH −2 species were about 50–400 times more reactive than the structural analogous Zn 2 ( m ‐12 N 3 O‐dimer) system.