452972-99-5Relevant articles and documents
Open-chain dications and betaines with imidazolium molecular motifs: Synthesis and structural aspects
Alcalde, Ermitas,Mesquida, Neus,Alemany, Montserrat,Alvarez-Rua, Carmen,Garcia-Granda, Santiago,Pacheco, Pedro,Perez-Garcia, Lluisa
, p. 1221 - 1231 (2002)
The synthesis of trinuclear open-chain prototypes gave variable yields: > 53% for dications 1·2X and 2·2X and > 80% for proton-ionizable dications 3·2X-5·2X incorporating 1H-1,2,4-triazole moieties. Deprotonation of the latter compounds resulted in the formation of the betaine counterparts 13·X-15·X. The courses of the dequaternization reactions of compounds 4·2X and 5·2X were also studied. The structural properties of dicationic protophanes 1·2X and 2·2X, containing bis(imidazolium) motifs, were examined by 1H and 13C NMR spectroscopy, electrospray mass spectrometry and by single-crystal X-ray diffraction analysis of the dication 1b·2PF6. Weak noncovalent interactions between the dications and the hexafluorophosphate ions bias the protophane conformation both in solution and in the solid state. X-ray diffraction reveals that the PF6- counterions are located in a channel formed by the dications (1b2+). Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
