Polyphosphorylated Triphenylenes: Synthesis, Crystal Structure, and Selective Catechol Recognition
Givelet, Cecile Tinant, Bernard Van Meervelt, Luc Buffeteau, Thierry Marchand-Geneste, Nathalie Bibal, Brigitte # ×
Amer chemical soc
Journal of Organic Chemistry vol:74 issue:2 pages:652-659
Designed as a multivalent hydrogen bond acceptor, new receptors, Discopus 1a,b, were built from a triphenylene core surrounded by six (diaryl)phosphinate groups. An efficient synthesis was developed to prepare these elaborated structures in a high overall yield. The X-ray structure of receptor 1b showed strong cooperative hydrogen bonds with two water molecules and intermolecular CH-pi contacts. In chloroform, Discopus la,b displayed recognition properties toward dihydroxybenzenes, selectively forming complexes with catechol derivatives 4a-c in a 1:2 (host:guest) stoichiometry. According to NMR and microcalorimetry titrations, association constants were found in the 30-2837 M-1 range, which were larger than those reported for curvated catechol receptors (14-120 M-1). Interestingly, Discopus present two distinct catechol binding sites. Weak hydrogen bonding between host phosphinates and guest hydroxyl groups was shown by infrared spectroscopy and P-31 NMR. Molecular dynamics simulations and recognition experiments suggested that a stronger hydrogen bond assisted by a pi-interaction between the Discopus core and one catechol molecule could exist within the :2 complex.