Acyclic Janus‐AT Nucleoside Host Channels Precisely Lock Water into Single‐File Wires with Local Rotational Flexibility. (5th June 2019) - Zhou, Xinglong
Abstract: Confining polar water molecules to particular geometries demands sophisticated intermolecular interactions, and not many small synthetic molecules have accomplished such a task. Herein, regioisomeric acyclic Janus‐AT nucleosides (1 and 2 ), with a self‐complementary fused genetic alphabet and conformationally flexible side chains, have been selectively synthesized. 1 and 2 adopt disparate base‐pair motifs from the π–π stacked hydrophobic base moieties and distinct hydrogen bond (HB) interconnections from the hydrophilic sugar residues, which in turn lead to divergent, intricate intermolecular interaction networks with different capacities to confine water molecules. Under the precise control of the host framework of the N 8 ‐regioisomer, separate ordered single‐file water wires can be locked through special three‐HB clamps into unique inter‐ and intra‐wire geometrical alignments. Localized dynamic synchronized rotations within the fixed framework coordinated by both the host hydroxy groups and guest water molecules were observed in a temperature‐induced reversible single‐crystal‐to‐single‐crystal transition (SCSCT). Abstract : In der Reihe tanzen : Unter präziser Kontrolle des Wirt‐Gerüsts des N 8 ‐Regioisomers acyclischer Janus‐TA‐Nucleoside können einreihige lineare Anordnungen von Wassermolekülen durch Klammern, die aus drei Wasserstoffbrücken bestehen, eingerastet werden. Zudem wurden in einem temperaturinduzierten reversiblen Einkristall‐zu‐Einkristall‐Übergang synchronisierte Rotationen innerhalb des fixierten Gerüsts beobachtet.