Acyclic Janus‐AT Nucleoside Host Channels Precisely Lock Water into Single‐File Wires with Local Rotational Flexibility

Abstract

Confining polar water molecules to particular geometries demands sophisticated intermolecular interactions, and not many small synthetic molecules have accomplished such at ask. Herein, regioisomeric acyclic Janus-ATn ucleosides (1 and 2), with as elf-complementary fused genetic alphabet and conformationally flexible side chains,have been selectively synthesized. 1 and 2 adopt disparate base-pair motifs from the p-p stackedh ydrophobic base moieties and distinct hydrogen bond (HB) interconnections from the hydrophilic sugar residues,w hichi nt urn lead to divergent, intricate intermolecular interaction networks with different capacities to confine water molecules.U nder the precise control of the host framework of the N 8 -regioisomer,s eparate ordered single-file water wires can be locked through special three-HB clamps into unique inter-and intra-wire geometrical alignments.L ocalizedd ynamic synchronized rotations within the fixedf ramework coordinated by both the host hydroxy groups and guest water molecules were observed in at emperature-induced reversible single-crystal-to-single-crystal transition (SCSCT).