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Observation of an Eclipsed C sp 3 ‐CH 3 Bond in a Tricyclic Orthoamide; Experimental and Theoretical Evidence for CH ⃛O Hydrogen Bonds
Author(s) -
Seiler Paul,
Weisman Gary R.,
Glendening Eric D.,
Weinhold Frank,
Johnson Van B.,
Dunitz Jack D.
Publication year - 1987
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.198711751
Subject(s) - hydrogen bond , chemistry , anhydrous , molecule , tricyclic , eclipsed conformation , crystallography , quantum chemical , crystal structure , computational chemistry , methyl group , group (periodic table) , stereochemistry , organic chemistry
The inversion of the rotational barrier of a methyl group can be accomplished by a suitable arrangement of water molecules, as shown by X‐ray crystal structure investigations of the orthoamide 1 . In the trihydrate, the methyl group adopts a nearly elipsed conformation, whereas in the anhydrous compound the normal staggered conformation is found. The H…O bond strengths of the C−H·O hydrogen bonds required for this inversion (ca. 1.8 kcal nol −1 ) were confirmed by quantum‐chemical calculations only when correlation effects were taken into consideration.