Interactions Between Cyclodextrins and TmIII Chelates of Polyazamacrocycles as Studied by NMR in Aqueous Solution

• Autor(a) principal: Zitha-Bovens, Emrin
• Data de Publicação: 1999
• Outros Autores: Bekkum, Herman van, Peters, Joop A., Geraldes, Carlos F. G. C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/8106; https://doi.org/10.1002/(SICI)1099-0682(19990202)1999:2<287::AID-EJIC287>3.0.CO;2-W

The interactions between α-, β-, and γ-CD and the TmIII chelates of the macrocyclic polyaminopolycarboxylates DOTA and NOTA were studied with the use of 1H- and 13C-NMR shift and relaxation rate measurements. Interactions were only observed between Tm(DOTA)- and γ-CD. The structure and the stability of the concerning supramolecular structures was elucidated by fitting of the NMR titration curves to a theoretical model. It appears that an inclusion compound is formed, where the hydrophobic macrocyclic part of the chelate sits in the γ-CD cavity. This inclusion compound binds a second Tm(DOTA)- molecule at the outside lower rim of the CD cone. The binding occurs probably via hydrogen bonds between non-chelated carboxylate oxygen atoms of the concerning Tm(DOTA)- and CH2OH groups of the γ-CD molecule, which are in a favorable position due to opening of the γ-CD cone angle as a result of the inclusion of the first γ-CD.