Document Type

Article

Publication Date

1-1-2017

Publication Title

CrystEngComm

Volume

19

Issue

30

First Page

4312

Last Page

4320

Abstract

The host-guest complexes of conformationally rigid C-ethyl-2-bromoresorcinarene with aromatic N-oxides were studied using single crystal X-ray crystallography. Unlike that of the conformationally more flexible C-ethyl-2-methylresorcinarene, the C-ethyl-2-bromoresorcinarene cavity forms endo-complexes only with the small pyridine-N-oxides, such as pyridine N-oxide, 2-methyl-, 3-methyl- and 4-methylpyrdine N-oxide, and quinoline N-oxide. The larger 2,4,6-trimethylpyridine, 4-phenylpyridine and isoquinoline N-oxide, and 4,4-bipyridine N,N′-dioxide and 1,3-bis(4-pyridyl)propane N,N′-dioxide do not fit into the host cavity. Instead endo-acetone complexes are formed. Remarkably, differing from the anti-gauche endo-complex with C-ethyl-2-methylresorcinarene, the flexible 1,3-bis(4-pyridyl)propane N,N′-dioxide guest forms an anti-anti exo-complex with C-ethyl-2-bromoresorcinarene. The endo- and exo-complexes of C-ethyl-2-bromoresorcinarene and studied N-oxides manifest C-O⋯Br, C-H⋯π and C-Br⋯π interactions.

DOI

10.1039/c7ce00975e

E-ISSN

14668033

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