New Triazole-Containing Branched Bis(dipeptidomimetic) – Switching from Self-Dimerization to Anion-Binding PropertiesThis work is supported by the UGC of HK (project no: AoE/P-03/08). The 700 MHz NMR spectrometer was funded by the UGC of HKSAR (SEG/CUHK09).
Received: 30 June 2017
Accepted after revision: 28 July 2017
25 August 2017 (eFirst)
Dedicated to Professor Victor Snieckus on the occasion of his 80th birthday
A triazole-containing branched bis(dipeptidomimetic) 2 using l-lysine as a flexible branching unit was synthesized and characterized. The compound was found to form weak dimers (K dim = 19 M–1) in chloroform as shown by vapor pressure osmometry (VPO) and concentration-dependent 1H NMR studies. On the other hand, the compound was capable of binding chloride and monobasic diethyl phosphate (DEP) in chloroform. Job plot analysis, MALDI-TOF mass spectrometry, and NMR titration studies revealed a 1:1 binding stoichiometry with good binding affinities (K a ≈ 640–780 M–1). Structural studies using ROESY NMR spectroscopy and molecular modelling on the 2–DEP complex indicated the adoption of a helix-like conformation by the host with the guest situated near the branching juncture.