resumo
The combination of the glycine-derivative supramolecular salt 4,6-bis(carboxymethylamino)-2-oxo-2,3-dihydro-1,3,5-triazin-1-ium chloride (H(2)bodt center dot HCl) and lanthanide(III) chloride hydrates under hydrothermal conditions (120 degrees C, 48 h) led to the formation of a family of isotypical materials formulated as [Ln(bodt)(Hbodt)] [where Ln(3+) = La3+ (1), (La0.95Eu0.05)(3+) (2) and (La0.95Tb0.05)(3+) (3)]. The synthesis of the novel precursor H(2)bodt center dot HCl is detailed. The structures of H(2)bodt center dot HCl and its intermediate compound were unveiled by single-crystal X-ray diffraction and characterized by standard liquid-state techniques. The crystallographic details of compound 1 were unveiled in the monoclinic P2/c space group by using single-crystal X-ray diffraction, with the crystal structure of 1 comprising a one-dimensional (1)(infinity)[La(bodt)(Hbodt)] coordination polymer. All polymeric materials were fully characterized by FT-IR, electron microscopy (SEM and EDS), powder X-ray diffraction, and elemental and thermogravimetric analyses. The photoluminescent properties of 1 and of the mixed-lanthanide materials 2 and 3 were investigated at ambient and low temperatures. An excited-state intermolecular proton transfer (ESPT) process, induced by intermolecular hydrogen-bonding interactions, is proposed to account for the observed anomalous emission and excitation spectra of 1. Aiming at providing an in-depth understanding of the emission (fluorescence and phosphorescence) properties of the ligand, time-dependent density functional theory (TD-DFT) calculations were also performed.
palavras-chave
METAL-ORGANIC FRAMEWORKS; CAMBRIDGE STRUCTURAL DATABASE; GRAPH-SET ANALYSIS; AMINO-ACID; NANOPOROUS MATERIALS; MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURES; ROOM-TEMPERATURE; PROTON-TRANSFER; EXCITED-STATES
categoria
Chemistry; Crystallography
autores
Vilela, SMF; Ananias, D; Silva, P; Nolasco, M; Carlos, LD; Bermudez, VD; Rocha, J; Tome, JPC; Paz, FAA
nossos autores
Duarte Ananias
Investigador Auxiliar
Filipe Alexandre Almeida Paz
Investigador Principal
João Rocha
Prof. Catedrático
Luís Carlos
Professor Catedrático
Mariela Martins Nolasco
Investigador Auxiliar
Patrícia Rodrigues da Silva
Bolseiro de investigação
Sérgio Manuel Felipe Vilela
Bolseiro de pós-DoutoramentoGrupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G6 - Materiais Virtuais e Inteligência Artificial
agradecimentos
We would like to thank Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE, Laboratorio Associado Centro de Investigacao em Materiais Ceramicos e Compositos - CICECO (Pest C-CTM/LA0011/2013), and the research unit QOPNA (PEst-C/QUI/UI0062/2013) for their general funding scheme. We further wish to thank FCT for the R&D project EXPL/CTM-NAN/0013/2013 (FCOMP-01-0124-FEDER-041282), for granting the funding to build the Iris multi-processor cluster, and for the doctoral and post-doctoral research grants [no. SFRH/BPD/94381/2013 (to SMFV), SFRH/BD/46601/2008 (to PS) and SFRH/BPD/32103/2006 (to MN)].