resumo
A novel beta-cyclodextrin (beta CD) inclusion compound was prepared using 4-phenylpyridine-N-oxide (PPNO) as the organic guest. The inclusion compound, beta CD.PPNO, was characterised both in solution and in the solid state using numerous techniques. H-1 NMR in aqueous solution allowed the determination of a 1 : 1 stoichiometry and an association constant of 164 +/- 21 M-1. Powder and single-crystal X-ray diffraction studies showed the formation of two distinct crystal phases, appearing at different timings. Over time, one of the crystal phases converts spontaneously into the other. This work is the first to monitor the conversion of different polymorphs of cyclodextrin inclusion compounds in real time.
palavras-chave
N-OXIDE DERIVATIVES; METAL-ORGANIC FRAMEWORKS; C-13 CHEMICAL-SHIFTS; BETA-CYCLODEXTRIN; SOLID-STATE; AQUEOUS-SOLUTION; ANTIMICROBIAL ACTIVITY; ALLIUM-STIPITATUM; SOLUTION NMR; COMPLEX
categoria
Chemistry; Crystallography
autores
Fernandes, JA; Ramos, AI; Ribeiro-Claro, P; Paz, FAA; Braga, SS
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
José Alberto Pires Fernandes
Bolseiro de pós-Doutoramento
Paulo Ribeiro-Claro
Professor Associado com Agregação
Susana Isabel Fonseca de Almeida Santos Braga
Investigadoragradecimentos
We acknowledge the Fundacao para a Ciencia e a Tecnologia (FCT), the European Union, the QREN, and the European Fund for Regional Development (FEDER), through the programme COMPETE, for general funding of QOPNA (project PEst C-QUI/UI0062/2013; FCOMP-01-0124-FEDER-037296) and CICECO (PEst C-CTM/LA0011/2013) and for specific funding of the purchase of the single-crystal X-ray diffractometer. The FCT and the European Social Fund are acknowledged for grant SFRH/BPD/63736/2009 (to JAF).