title: Microwave spectra and barrier to internal rotation in cyclopropylmethylsilane.
abstract: Rotational spectra for 3 silicon isotopologues (28Si, 29Si, 30Si) of cyclopropylmethylsilane (c-C3H5SiH2CH3) have been observed in natural abundance using Fourier-transform microwave spectroscopy, and the dipole moment of the most abundant (28Si) isotopologue has been determined using the Stark effect. The observed rotational constants (A = 8800.5997(9) MHz; B = 2238.6011(3) MHz; C = 2001.0579(3) MHz) and dipole moment components (mu(a) = 0.195(2) D, mu(b) = 0.674(11) D, mu(c) = 0.362(19) D, mu(total) = 0.790(13) D) for the 28Si species are consistent with ab initio predictions (MP2/6-311+G(d)) for a gauche conformation about the Si-cyclopropyl bond. All of the observed transitions were split into doublets due to internal rotation of the methyl group, allowing a determination of the V3 barrier to internal rotation of 6.671(9) kJ mol(-1) for the most abundant isotopologue. This barrier will be compared to those for other Si-CH(3) containing compounds and will be related to a partial structure determination from the available microwave and ab initio data.
authors.affiliation: Department of Chemistry, Eastern Illinois University, 600 Lincoln Avenue, Charleston, Illinois 61920, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Foellmer
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Murray
authors.forename: Michal M
authors.initials: MM
authors.lastname: Serafin
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Steber
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Peebles
authors.forename: Sean A
authors.initials: SA
authors.lastname: Peebles
authors.forename: Joshua L
authors.initials: JL
authors.lastname: Eichenberger
authors.forename: Gamil A
authors.initials: GA
authors.lastname: Guirgis
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Wurrey
authors.forename: James R
authors.initials: JR
authors.lastname: Durig