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Structural Changes of Di(2‐pyridyl) Ketone on Single and Twofold Protonation
Author(s) -
Bock Hans,
Van Tran T. H.,
Schödel Holger,
Dienelt Rüdiger
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199804)1998:4<585::aid-ejoc585>3.0.co;2-b
Subject(s) - chemistry , protonation , dication , ketone , hydrogen bond , pyridine , photochemistry , medicinal chemistry , molecule , organic chemistry , ion
Di(2‐pyridyl) ketone, intricately twisted due to its two n N σ and one n O σ lone pairs, exhibits tremendous structural differences on single and double protonation to salts containing either the anion [B(C 6 H 5 ) 4 ] − , which cannot be protonated, or Cl − , which accepts two hydrogen bonds. In the monocation, generated in acetic acid with added sodium tetraphenylborate, the pyridine rings of di(2‐pyridyl) ketone are planarized due to the formation of an intermolecular hydrogen bond. Aqueous hydrogen chloride produces a dication with both nitrogen centers protonated and the resulting di(2‐pyridyl) ketone hydrate embedded in a complex hydrogen‐bond network. Extensive quantum‐chemical calculations based on the experimental structural data allow to rationalize the unexpected results.