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RESEARCH PRODUCT

Host-Guest Complexes of C-Ethyl-2-methylresorcinarene and Aromatic

Puttreddy RakeshBeyeh Ngong KodiahRas Robin H ARissanen Kari

subject

conformationFull PaperNN′-dioxidesresorcinarenesweak interactionsFull Paperssupramolecular chemistry

description

Abstract The C‐ethyl‐2‐methylresorcinarene (1) forms 1:1 in‐cavity complexes with aromatic N,N′‐dioxides, only if each of the aromatic rings has an N−O group. The structurally different C‐shaped 2,2′‐bipyridine N,N′‐dioxide (2,2′‐BiPyNO) and the linear rod‐shaped 4,4′‐bipyridine N,N′‐dioxide (4,4′‐BiPyNO) both form 1:1 in‐cavity complexes with the host resorcinarene in C 4v crown and C 2v conformations, respectively. In the solid state, the host–guest interactions between the 1,3‐bis(4‐pyridyl)propane N,N′‐dioxide (BiPyPNO) and the host 1 stabilize the unfavorable anti‐gauche conformation. Contrary to the N,N′‐dioxide guests, the mono‐N‐oxide guest, 4‐phenylpyridine N‐oxide (4PhPyNO), does not form an in‐cavity complex in the solid state. The host–guest complexation and the relative guest affinities were studied through 1H NMR competition experiments in methanol. Single‐crystal X‐ray crystallography of the 1:1 complexes supports the proposed solution‐state structures, also revealing strong hydrogen bonds between the host and the guests, not observed in solution owing to hydrogen/deuterium (H/D) exchange processes in methanol.

10.1002/open.201700026https://pubmed.ncbi.nlm.nih.gov/28638775