A branched, hydrogen-bonded heterodimer: a novel system for achieving high stability and specificity

Presented is a description of the design, synthesis, and characterization of a novel, branched, six hydrogen-bonded heterodimer termed 'trident'. Two branched oligoamide molecules, 1 and 2, with complementary hydrogen-bonding sequences 3(AD) and 3(DA), respectively, were found to form a very stable (Ka≥9×106 M−1) heterodimer in chloroform. Confirmation of the high stability of the heterodimer was obtained through 1D and 2D 1H NMR spectroscopy, thin-layer chromatography (TLC), and vapor pressure osmometry (VPO). The stability of the trident occurs through the cooperative action of six programmed hydrogen-bonding interactions, which are facilitated by the pre-organization of the individual strands through intramolecular hydrogen bonding.

A 1:1 ratio of synthesized oligoamides 1 and 2 tightly bind in chloroform to form a very stable six hydrogen-bonded heterodimer 1·2.