Efficient Self-Assembly in Water of Long Noncovalent Polymers by Nucleobase Analogues

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• 作者：Brian J. Cafferty ; Isaac G谩llego ; Michael C. Chen ; Katherine I. Farley ; Ramon Eritja ; Nicholas V. Hud
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：February 20, 2013
• 年：2013
• 卷：135
• 期：7
• 页码：2447-2450
• 全文大小：266K
• 年卷期：v.135,no.7(February 20, 2013)
• ISSN：1520-5126

文摘

Molecular self-assembly is widely appreciated to result from a delicate balance between several noncovalent interactions and solvation effects. However, current design approaches for achieving self-assembly in water with small, synthetic molecules do not consider all aspects of the hydrophobic effect, in particular the requirement of surface areas greater than 1 nm² for an appreciable free energy of hydration. With the concept of a minimum hydrophobic surface area in mind, we designed a system that achieves highly cooperative self-assembly in water. Two weakly interacting low-molecular-weight monomers (cyanuric acid and a modified triaminopyrimidine) are shown to form extremely long supramolecular polymer assemblies that retain water solubility. The complete absence of intermediate assemblies means that the observed equilibrium is between free monomers and supramolecular assemblies. These observations are in excellent agreement with literature values for the free energy of nucleic acid base interactions as well as the calculated free energy penalty for the exposure of hydrophobic structures in water. The results of our study have implications for the design of new self-assembling structures and hydrogel-forming molecules and may provide insights into the origin of the first RNA-like polymers.