abstract
The binding affinities of three new tetraaza[2]arene[2]triazine based macrocycles anchoring one (AC1A) and two (AC2A and Me(4)AC2A) t-alanine amino acid units for five aromatic carboxylate anions (bz(-), ph(2-), iph(2-), tph(2-) and btc(3-)) were investigated in DMSO-d(6). H-1 NMR titrations revealed that the AC1A and AC2A receptors exhibit comparable anion affinities, suggesting that the two t-alanine binding units in AC2A are not simultaneously involved in the anion recognition as indicated by molecular dynamics simulations carried out for selected AC1A and AC2A associations using the AMBER force field (GAFF). New force field parameters were developed in order to mimic the structural singularity derived from the N-H macrocyclic bridges. (C) 2011 Elsevier Ltd. All rights reserved.
keywords
DIMETHYL-SULFOXIDE; MOLECULAR RECOGNITION; CAVITY; COMPLEXATION; ACIDS; DEPROTONATION; EQUILIBRIA; CHEMISTRY; TRIAZINE; FLUORIDE
subject category
Chemistry
authors
Vicente, AI; Caio, JM; Sardinha, J; Moiteiro, C; Delgado, R; Felix, V
our authors
Ana Isabel Ferreira Franco Vicente
PhD Student
Vítor Félix
Associate Professor with Aggregationacknowledgements
This work was funded through the Operational Program Competitiveness Factors-COMPETE and National Funds through FCT-Fundacao para a Ciencia e a Tecnologia under project PTDC/QUI/68582/2006. Authors thank to Helena Santos (ITQB) and Pedro Lamosa (ITQB) for the NMR interpretation and technical assistance and Pedro Vaz by the mass spectrometry data acquisition. Acknowledgements are also due to the National NMR (contract REDE/1517/RMN/2005) and Mass Spectrometry (REDE/1501/REM/2005) networks supported by National Program for Scientific Re-equipment, with funds from POCI 2010 (FEDER) and FCT by use of these facilities. A.I.V. and J.M.C. also thank FCT for the Ph.D. scholarships SERH/BD/32487/2006 and SFRH/BD/66789/2009, respectively.