Rigid small-molecule DNA hybrids (rSMDHs) have been synthesized with three DNA strands attached to a rigid tris(phenylacetylene) core. When combined under dilute conditions, complementary rSMDHs form cage dimers that melt at >10 degrees C higher and much sharper than either unmodified DNA duplexes or rSMDH aggregates formed at higher concentrations. With a 2.97 average number of cooperative duplexes, these caged dimers constitute the first example of cooperative melting in well-defined DNA-small-molecule structures, demonstrating the important roles that local geometry and ion concentration play in the hybridization/dehybridization of DNA-based materials.

Over the past few years, efforts in the laboratory of the corresponding author (S. T. Nguyen) have overwhelmingly suggested that the reported melting data for small molecule-DNA hybrids, as presented in Table 1 and Figure 2 of this publication, are incorrect. While small molecule-DNA hybrids do display sharper melting profiles compared to those for unmodified DNA duplexes, the levels of cooperativity are more modest, as shown in our subsequent works. 1,2 As a result, the corresponding author withdraws this publication and regrets any trouble it might have caused.