An Ab initio study on the conformations of protonated, neutral, and deprotonated amidine

Theresa Julia Zielinski, Michael R. Peterson, Imre G. Csizmadia, Robert Rein

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Ab initio SCF molecular orbital calculations have been performed to ascertain the conformational preferences of protonated, neutral, and deprotonated amidine [HC(NH)NH2], using the 3‐21G split valence basis set. The states of eight stable species, eight transition states, and four higher‐order saddle points have been determined by complete geometry optimization utilizing analytic energy gradient techniques. Protonation at the amidine NH is preferred over the –NH2 site by 37.1 kcal/mol. Neutral amidine has rotational barriers of 9.6 and 11.7 kcal/mol for the HNCN cis and trans isomers, respectively, while all the stable HC(NH2)2+ and HC(NH)2 species possess torsional barriers larger than 23 kcal/mol. There is, however, essentially free C—N single‐bond rotation in HC(NH)NH3+, the calculated barriers being 0.7 and 1.8 kcal/mol for the cis and trans HNCN isomers, respectively.

Original languageEnglish
Pages (from-to)62-68
Number of pages7
JournalJournal of Computational Chemistry
Volume3
Issue number1
DOIs
Publication statusPublished - Jan 1 1982

ASJC Scopus subject areas

  • Chemistry(all)
  • Computational Mathematics

Fingerprint Dive into the research topics of 'An Ab initio study on the conformations of protonated, neutral, and deprotonated amidine'. Together they form a unique fingerprint.

  • Cite this