Work

A Long‐Lived Halogen‐Bonding Anion Triple Helicate Accommodates Rapid Guest Exchange

Year: 2018

Type: article

Abstract: Anion-templated helical structures are emerging as a dynamic and tractable class of supramolecules that exhibit anion-switchable self-assembly. We present the first kinetic studies of an anion helicate by utilizing halogen-bonding m-arylene-ethynylene oligomers. These ligands formed high-fidelity triple helicates in solution with surprisingly long lifetimes on the order of seconds even at elevated temperatures. We propose an associative ligand-exchange mechanism that proceeded slowly on the same timescale. In contrast, intrachannel anion exchange occurred rapidly within milliseconds or faster as determined by stopped-flow visible spectroscopy. Additionally, the helicate accommodated bromide in solution and the solid state, while the thermodynamic stability of the triplex favored larger halide ions (bromide≈iodide≫chloride). Taken together, we elucidate a new class of kinetically stable helicates. These anion-switchable triplexes maintain their architectures while accommodating fast intrachannel guest exchange.

Source: Angewandte Chemie International Edition

DOI: 10.1002/anie.201810415

Authors: Casey J. Massena, Daniel A. Decato, Orion B. Berryman

Institution: University of Montana

Language: English

Topic: Supramolecular Chemistry and Complexes

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: Montana University System, National Institute of General Medical Sciences, Division of Chemistry

Awards: G1310521215, G354619025, G8048338848, Biomolecular Structure and Dynamics