Pronounced conformational preferences in 1,4-disubstituted but-2-ynes

Leo Radom*, Peter J. Stiles, Mark A. Vincent

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Internal rotation in 1,4-disubstituted but-2-ynes XCH2CCCH2Y (X, Y = H, CH3, Li, F) has been studied with the aid of ab initio molecular orbital theory. When either or both of X and Y are approximately electroneutral (H or CH3), the barrier to internal rotation is very small. On the other hand, when X and Y are both electropositive (LiCH2CCCH2Li) or both electronegative (FCH2CCCH2F), there are pronounced preferences for conformations in which the dihedral angle XC·CY is slightly greater than 90°. When X is electropositive and Y electronegative (LiCH2CCCH2F), the stable rotational isomers are cis and trans with the former being preferred. For all molecules examined here the threefold component of the torsional potential function is very small.

Original languageEnglish
Pages (from-to)259-270
Number of pages12
JournalJournal of Molecular Structure
Issue number2
Publication statusPublished - 1978
Externally publishedYes


Dive into the research topics of 'Pronounced conformational preferences in 1,4-disubstituted but-2-ynes'. Together they form a unique fingerprint.

Cite this