title: Molecular Structure of 3,4-Dimethylenehexa-1,5-diene ([4]Dendralene), C(8)H(10), in the Gas Phase As Determined by Electron Diffraction and ab Initio Calculations.
abstract: The molecular structure of 3,4-dimethylenehexa-1,5-diene ([4]dendralene), C(8)H(10), has been determined in the gas phase. A single conformer with C(2) symmetry, having two almost planar, anti butadiene groups orientated with a dihedral angle C(2)C(3)C(4)C(5) of 71.7(19) degrees, is detected by electron diffraction employing flexible restraints derived from ab initio computations. Other experimental structural parameters (r(alpha)/pm, angle(alpha)/ degrees ) are: C(1)=C(2) 133.4(1), C(3)=C(7) (not in main chain) 134.0(1), C(2)-C(3) 147.4(2), C(3)-C(4) 149.6(3), C(1)C(2)C(3) 124.4(3), C(2)C(3)C(4) 119.2(5), C(4)C(3)C(7) 117.6(7), and C(7)C(3)C(2)C(1) -174.8(28). Ab initio computations at the MP2/6-311G level predict that the vapor consists of ca. 90% of the conformer found experimentally, the other 10% comprising four other conformers.
authors.affiliation: Department of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K.
authors.forename: Paul T.
authors.initials: PT
authors.lastname: Brain
authors.forename: Bruce A.
authors.initials: BA
authors.lastname: Smart
authors.forename: Heather E.
authors.initials: HE
authors.lastname: Robertson
authors.forename: Martin J.
authors.initials: MJ
authors.lastname: Davis
authors.forename: David W. H.
authors.initials: DW
authors.lastname: Rankin
authors.forename: William J.
authors.initials: WJ
authors.lastname: Henry
authors.forename: Ian
authors.initials: I
authors.lastname: Gosney