Theoretical Studies on Hydrogen Bonds in Anions Encapsulated by an Azamacrocyclic Receptor

Wang, Jing; Gu, Jiande; Hossain, Md. Alamgir; Leszczyński, Jerzy

doi:10.3390/cryst6030031

Cited by 2 publications

(1 citation statement)

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“…The rationalization of the mechanisms of growth of specific molecular networks is challenging and benefits from the fundamental insights and the validation of computational methods gained from the study of precursor macrocycle–anion clusters. The conformational landscape of these clusters can actually become quite complex, depending on the size of the macrocycle and on the degree of protonation of its amine groups (Boudon et al, 1991; Ilioudis and Steed, 2001; Warden et al, 2004a,b; Wichmann et al, 2006; Mateus et al, 2010; Wang et al, 2016). The aim of this work is to contribute to the understanding of the anionic supramolecular chemistry of azamacrocycles through the characterization of benchmark aggregates involving the binding of Cl − to protonated cyclen (tetraazacyclododecane).…”

Section: Introductionmentioning

confidence: 99%

A Cl− Hinge for Cyclen Macrocycles: Ionic Interactions and Tweezer–Like Complexes

2019

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The supramolecular networks derived from the complexation of polyazamacrocycles with halide anions constitute fundamental building blocks of a broad range of modern materials. This study provides insights into the conformational framework that supports the binding of protonated cyclen macrocyles (1,4,7,10-Tetraazacyclododecane) by chloride anions through NH δ+ ···Cl − interactions. The isolated complex comprised of two cyclen hosts linked by one Cl − anion is characterized by means of infrared action spectroscopy and ion mobility mass spectrometry, in combination with quantum chemical computations. The Cl − anion is found to act as a hinge that bridges the protonated moieties of the two macrocycles leading to a molecular tweezer configuration. Different types of conformations emerge, depending on whether the trimer adopts an open arrangement, with significant freedom for internal rotation of the cyclen moieties, or it locks in a folded conformation with intermolecular H-bonds between the two cyclen backbones. The ion mobility collision cross section supports that folded configurations of the complex are dominant under isolated conditions in the gas phase. The IRMPD spectroscopy experiments suggest that two qualitatively different families of folded conformations coexist at room temperature, featuring either peripheral or inner positions of the anion with respect to the macrocycle cavities, These findings should have implications in the growth of extended networks in the nanoscale and in sensing applications.

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