Highly constrained guests in complexes of p-tert-butylcalix[6]arene dianion: pentane-1,5-diammonium and choline

LAZZAROTTO, MáRCIO ; FERREIRA, CREUSA IARA ; CASTELLANO, EDUARDO ERNESTO ; VEGLIA, ALICIA VIVIANA

JOURNAL OF MOLECULAR STRUCTURE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 1067 p. 88 - 93

0022-2860

Este manuscrito fue enviado el 3-12-13 y fue aceptado el 6 de marzo de 2014 The structures of the complexes of choline and pentane-1,5-diammonium with p-t-bu-calix[6]arene dianion were determined. Both salts display the calixarene moiety at 1,2,3-alternate conformation, with two concave surfaces formed by three aromatic rings, and the phenolate units are at distal positions, interacting with two phenol units by hydrogen bonds.p-t-bu-calix[6]arene dianion were determined. Both salts display the calixarene moiety at 1,2,3-alternate conformation, with two concave surfaces formed by three aromatic rings, and the phenolate units are at distal positions, interacting with two phenol units by hydrogen bonds. The salt of pentane-1,5-diammonium shows the diammonium connecting both calixarene dianion units, and one NH3+ is located endo-calix position and the other occupies an exo-calix position. The t-butyl groups and the calix cavity constrains the pentane-1,5-diammonium chain to near syneclipsed and gauche conformations. The other semi-calix accomodates a THF solvent molecule. The salt of choline shows the trimethylammonium groups of choline units immersed in these concave surfaces, with several interactions N+-C-H---ð interactions with the aromatic semi-cavities.