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Computational NMR Spectra of o ‐Benzyne and Stable Guests and Their Hemicarceplexes
Author(s) -
Castro Abril C.,
RomeroRivera Adrian,
Osuna Sílvia,
Houk K. N.,
Swart Marcel
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904756
Subject(s) - aryne , chemical shift , supramolecular chemistry , chemistry , molecule , adduct , density functional theory , ring (chemistry) , nmr spectra database , computational chemistry , characterization (materials science) , carbon 13 nmr , stereochemistry , crystallography , spectral line , materials science , nanotechnology , organic chemistry , physics , astronomy
The incarceration of o ‐benzyne and 27 other guest molecules within hemicarcerand 1 , as reported experimentally by Warmuth, and Cram and co‐workers, has been studied by density functional theory (DFT). The 1 H NMR chemical shifts, rotational mobility, and conformational preference of the guests within the supramolecular cage were determined, which showed intriguing correlations of the chemical shifts with structural parameters of the host–guest system. Furthermore, based on the computed chemical shifts reassignments of some NMR signals are proposed. This affects, in particular, the putative characterization of the volatile benzyne molecule inside a hemicarcerand, for which our CCSD(T) and KT2 results indicate that the experimentally observed signals are most likely not resulting from an isolated o ‐benzyne within the supramolecular host. Instead, it is shown that the guest reacted with an aromatic ring of the host, and this adduct is responsible for the experimentally observed signals.