Halogen bonding as a key interaction in the self‐assembly of iodinated diphenylalanine peptides

Abstract

AbstractThe diphenylalanine peptide FF (H2N‐Phe‐Phe‐COOH) is a simple building‐block that has been extensively studied for multiple purposes. Among the many possible mutations finalized to tailor specific functions and properties of FF‐based materials, halogenation was marginally considered despite the huge changes it confers to molecular self‐assembly. Here, we report a detailed study on the role of halogenation, specifically iodination, in the aggregation behavior of iodine‐modified FF dipeptides. Single‐crystal X‐ray structures of mono‐iodinated—F(I)F—and bis‐iodinated—F(I)F(I)—diphenylalanine reveal that halogen atoms exert a key role in the packing features of these compounds. Specifically, halogen bonding provides additional stability to the dry interfaces formed by the aromatic rings, providing a contribution in the solid‐state packing of these dipeptides. The structural evidence of halogen bonding as crucial noncovalent interaction confirms the great potential of halogenation as supramolecular tool for peptide‐based systems.