Microwave spectrum, molecular structure, barrier to internal rotation, and dipole moment of methyl monofluorogermane

Journal Article · Tue Jun 15 04:00:00 EDT 1976 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.432176· OSTI ID:7286742

Roberts, R F; Varma, R; Nelson, J F

Microwave rotational spectra of twelve isotopic species of methyl monofluorogermane (CH/sub 3/GeH/sub 2/F, /sup 13/CH/sub 3/GeH/sub 2/F, and CD/sub 3/GeH/sub 2/F with Ge=/sup 70/Ge, /sup 72/Ge, /sup 74/Ge, and /sup 76/Ge) have been assigned in the 8 to 32 GHz frequency range. Differences in the effective moments of inertia of the /sup 70/Ge, /sup 72/Ge, and /sup 74/Ge species and information obtained from internal rotation analysis concerning the orientation of the -CH/sub 3/ group with respect to the C--Ge bond axis have been utilized with the assumptions r (Ge--H) =1.525 A and angleHGeH=110degree to calculate the following r/subs/ structural parameters for methyl monofluorogermane: r (C--Ge) =1.925 +- 0.002 A, r (C--H) =1.094 +- 0.005 A, r (Ge--F) =1.751 +- 0.005 A, angleHCH=108degree56' +- 20', angleFGeC=106degree20' +- 20'. Analysis of ground state rotational transition splittings yield potential barriers to internal rotation of 941 +- 20 and 921 +- 20 cal/mole for the -CH/sub 3/ and -CD/sub 3/ species of the molecule, respectively. Internal rotation analyses indicate that the symmetry axes of the -CH/sub 3/ and -CD/sub 3/ groups are not coincident with the respective C--Ge bond axes. It has been determined that these groups are tilted toward the Ge--F bond by 1degree54' +- 15' and 1degree51' +- 15' in CH/sub 3/ /sup 74/GeH/sub 2/F and CD/sub 3/ /sup 74/GeH/sub 2/F, respectively. Stark effect measurements on CD/sub 3/ /sup 74/GeH/sub 2/F yield principal axis dipole components of vertical-bar..mu../suba/vertical-bar=2.42 +- 0.12 D, vertical-bar..mu../subb/vertical-bar=0.93 +- 0.14 D, and a total dipole moment vertical-bar..mu..vertical-bar=2.59 +- 0.16 D, which is inclined at an angle of 23degree with the Ge--F bond and an angle of 51degree with the C--Ge bond. (AIP)

• Research Organization: Department of Chemistry, New York University, New York, New York 10003
• OSTI ID: 7286742
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 64:12; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
BOND ANGLE
BOND LENGTHS
CARBON 13
CARBON ISOTOPES
DEUTERIUM
DIPOLE MOMENTS
ELECTRIC DIPOLE MOMENTS
ELECTRIC MOMENTS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FLUORIDES
FLUORINE COMPOUNDS
GERMANES
GERMANIUM 70
GERMANIUM 72
GERMANIUM 74
GERMANIUM 76
GERMANIUM COMPOUNDS
GERMANIUM FLUORIDES
GERMANIUM ISOTOPES
HALIDES
HALOGEN COMPOUNDS
HYDROGEN ISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
MICROWAVE SPECTRA
MOTION
NUCLEI
ODD-ODD NUCLEI
ROTATION
SPECTRA
STABLE ISOTOPES