5371-70-0Relevant articles and documents
New coumarin dipicolinate europium complexes with a rich chemical speciation and tunable luminescence
Di Pietro, Sebastiano,Iacopini, Dalila,Moscardini, Aldo,Bizzarri, Ranieri,Pineschi, Mauro,Di Bussolo, Valeria,Signore, Giovanni
, (2021)
Europium (III) luminescent chelates possess intrinsic photophysical properties that are extremely useful in a wide range of applications. The lack of examples of coumarin-based lanthanide complexes is mainly due to poor photo-sensitization attempts. However, with the appeal of using such a versatile scaffold as antenna, especially in the development of responsive molecular probes, it is worth the effort to research new structural motifs. In this work, we present a series of two new tris coumarin-dipicolinate europium (III) complexes, specifically tailored to be either a mono or a dual emitter, tuning their properties with a simple chemical modification. We also encountered a rich chemical speciation in solution, studied in detail by means of paramagnetic NMR and emission spectroscopy.
Electron transfer pathways in photoexcited lanthanide(iii) complexes of picolinate ligands
Kovacs, Daniel,Kocsi, Daniel,Wells, Jordann A. L.,Kiraev, Salauat R.,Borbas, K. Eszter
supporting information, p. 4244 - 4254 (2021/04/06)
A series of luminescent lanthanide(iii) complexes consisting of 1,4,7-triazacyclononane frameworks and three secondary amide-linked carbostyril antennae were synthesised. The metal binding sites were augmented with two pyridylcarboxylate donors yielding octadentate ligands. The antennae carried methyl, methoxymethyl or trifluoromethyl substituents in their 4-positions, allowing for a range of excited state energies and antenna electronic properties. The1H NMR spectra of the Eu(iii) complexes were found to be analogous to each other. Similar results were obtained in the solid-state by single-crystal X-ray crystallography, which showed the structures to have nine-coordinate metal ions with heavily distorted tricapped trigonal prismatic geometries. Steady-state and time-resolved luminescence spectroscopy showed that the antennae could sensitize both Tb(iii) and Eu(iii), however, quantum yields were lower than in other octadentate complexes lacking pyridylcarboxylate. Complexes with more electron-poor pyridines were less emissive even when equipped with the same antenna. The oxidation and reduction potentials of the antennae and the pyridinecarboxylates, respectively, were determined by cyclic voltammetry. The obtained values were consistent with electron transfer from the excited antenna to the pyridine providing a previously unexplored quenching pathway that could efficiently compete with energy transfer to the lanthanide. These results show the crucial impact that photophysically innocent ligand binding sites can have on lanthanide luminescence.
FUSED HETEROCYCLIC DERIVATIVES, THEIR PREPARATION METHODS THEREOF AND MEDICAL USES THEREOF
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Paragraph 0246; 0252; 0459; 0460-0462, (2019/07/03)
The present invention relates to fused heterocyclic derivatives, processes for their preparation and their use in medicine. Specifically, the present invention relates to a novel derivative represented by the formula (I′), or its pharmaceutically acceptable salt thereof, a pharmaceutical composition containing the derivative or its pharmaceutically acceptable salt thereof, and the method for preparing the derivative and its pharmaceutically acceptable salt thereof. The present invention also relates to the use of the derivative and its pharmaceutically acceptable salt thereof, or a pharmaceutical composition containing the derivative and its pharmaceutically acceptable salt thereof in the preparation of medicines, in particularly as IDO inhibitor medicines, for treating and/or preventing cancers. Wherein each substituent of the formula (I′) is the same as defined in the specification.
