Microwave Spectrum and Structure of Bicyclo[1.1.0]butane

Abstract

The microwave spectra of four isotopic species of bicyclo[1.1.0] butane have been investigated and the rotational constants of each species have been determined. Combining these data with those of the previously studied normal isotopic species, a complete set of structural parameters have been found. These include C₁–C₃ = 1.497 Å, C₃–C₄ = 1.498 Å, C₃–C₆ = 1.071 Å, C–H (methylene) = 1.093 Å, ∠C₁C₃H₆ = 128°22′, dihedral angle, $\alpha$ , between cyclopropane rings = 121°40′, ∠HCH = 115°34′. These results are discussed with regard to the electronic structure of the molecule.