Model-driven engineering of supramolecular buffering by multivalency.

A supramolecular system in which the concentration of a molecule is buffered over several orders of magnitude is presented. Molecular buffering is achieved as a result of competition in a ring-chain equilibrium of multivalent ureidopyrimidinone monomers and a monovalent naphthyridine molecule which acts as an end-capper. While we previously only considered divalent ureidopyrimidinone monomers we now present a model-driven engineering approach to improve molecular buffering using multivalent ring-chain systems. Our theoretical models reveal an odd-even effect where even-valent molecules show superior buffering capabilities. Furthermore, we predict that supramolecular buffering can be significantly improved using a tetravalent instead of a divalent molecule, since the tetravalent molecule can form two intramolecular rings with different "stabilities" due to statistical effects. Our model predictions are validated against experimental (1)H NMR data, demonstrating that model-driven engineering has considerable potential in supramolecular chemistry.