Collect. Czech. Chem. Commun. 2002, 67, 1061-1083

Investigations of Electronic Interactions Between closo-Boranes and Triple-Bonded Substituents

Piotr Kaszynskia,*, Serhii Pakhomova and Victor G. Young, Jr.b

a Organic Materials Research Group, Department of Chemistry, Vanderbilt University, Nashville, TN 37235, U.S.A.
b X-Ray Crystallographic Laboratory, Department of Chemistry, University of Minnesota, Twin Cities, MN 55455, U.S.A.


Intramolecular electronic interactions were investigated in five series of 12-, 10-, and 6-vertex closo-boranes and hydrocarbons (benzene, acetylene, bicyclo[2.2.2]octane, and cubane) substituted with triple-bonded groups Y≡Z (C≡CR, C≡N, C≡O, and N≡N). Structural data (single crystal X-ray crystallography), spectroscopic properties (UV, IR, and NMR), chemical behavior (dediazoniation reactions), and electronic structure calculations (hybridization and π bond order) are all in agreement that the degree of electronic conjugation between the cluster and the Y≡Z substituent is lowest for the 12-vertex closo-borane and highest for the 6-vertex analog.

Keywords: Carboranes; Boranes; Structure elucidation; Ab initio calculations; π Interactions; Electron transmission; X-Ray diffraction; Substituent effects.

References: 68 live references.