THE COORDINATION COMPOUNDS Gd (III) AND Dy(III) WITH SOME β-DIKETONES

New complexes of Dy (III) and Gd (III) with b-diketones containing unsaturated and aryl substituents were synthesized. Metal polymers based on synthesized complexes were obtained by the method of radical polymerization. The composition and structure of synthesized complexes and metal polymers are established. It is shown that during polymerization the coordination environment of the central ion remains unchanged. The spectral-luminescent cha­racteristics of the synthesized compounds were studied. The presence of water molecules in the immediate coordination environment causes a low intensity of emission of monomeric dysprosium complexes. In the luminescence spectra of metal polymers, there are bands magnetic dipole transition (4F9 → 6H15/2) and electric dipole transition (4F9 → 6H13/2). The close energies of the triplet level of the ligand and the resonant level of the dysprosium ion cause low emission characteristics of the synthesized dysprosium complexes.

Extracting relational facts based on hybrid Syntax-Guided transformer and pointer network

Joint extraction of entities and relations from unstructured text is an essential step in constructing a knowledge base. However, relational facts in these texts are often complicated, where most of them contain overlapping triplets, making the joint extraction task still challenging. This paper proposes a novel Sequence-to-Sequence (Seq2Seq) framework to handle the overlapping issue, which models the triplet extraction as a sequence generation task. Specifically, a unique cascade structure is proposed to connect transformer and pointer network to extract entities and relations jointly. By this means, sequences can be generated in triplet-level and it speeds up the decoding process. Besides, a syntax-guided encoder is applied to integrate the sentence’s syntax structure into the transformer encoder explicitly, which helps the encoder pay more accurate attention to the syntax-related words. Extensive experiments were conducted on three public datasets, named NYT24, NYT29, and WebNLG, and the results show the validity of this model by comparing with various baselines. In addition, a pre-trained BERT model is also employed as the encoder. Then it comes up to excellent performance that the F1 scores on the three datasets surpass the strongest baseline by 5.7%, 5.6%, and 4.4%.

Tailoring the triplet level of isomorphic Eu/Tb mixed MOFs for sensitive temperature sensing

Different thermo-responsive fluorescence thermometers were obtained by regulating the triplet energy level of organic ligands within isostructural Eu/Tb mixed MOFs.

Steric shielding vs. σ–π orbital interactions in triplet–triplet energy transfer

Fine tuning of the benzoylthiophene triplet level through σ–π orbital interactions modifies the energy transfer rate constants to appropriate acceptors.