Molecular recognition by multiple metal coordination inside wavy-stacked macrocycles

• Published in: Nature communications Vol. 8; no. 1; p. 129
• Main Authors: Nakamura, Takashi, Kaneko, Yuya, Nishibori, Eiji, Nabeshima, Tatsuya
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 25.07.2017; Nature Portfolio
• Subjects: 639/638/541; 639/638/911; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-00076-8

Most biological and synthetic receptors for small organic molecules employ a combination of relatively weak intermolecular interactions such as hydrogen bonds. A host compound that utilizes stronger yet reversible bonding in a synergistic manner could realize precise recognition, but the regulation and spatial arrangement of such reactive interaction moieties have been a challenge. Here, we show a multinuclear zinc complex synthesized from a macrocyclic ligand hexapap, which inwardly arranges labile metal coordination sites for external molecules. The metallomacrocycle forms a unique wavy-stacked structure upon binding a suitable length of dicarboxylic acids via multipoint coordination bonding. The saddle-shaped deformation and dimerization realize the differentiation of the interaction moieties, and change of guest-binding modes at specific metal coordination sites among the many present have been achieved utilizing acid/base as external stimuli. Synergistic use of coordination bonds that are strong and reversible realizes unique molecular recognition in artificial systems. Here, the authors show that a zinc-based metallomacrocyle can bind dicarboxylic acids of suitable length at specific metal sites by shape deformation and dimerization.