Pure rotational spectra of the 37ClZnCH3, ClZnCD3, and ClZn13CH3 isotopologues of monomeric ClZnCH3 (X̃1A1) have been recorded using millimeter-wave direct absorption techniques in the frequency range 263–303 GHz. These species were synthesized in the gas phase in a DC discharge by the reaction of zinc vapor, produced in a Broida-type oven, with 37ClCH3 (in natural chlorine abundance), ClCD3, or Cl13CH3. Five to eight rotational transitions J + 1 ← J consisting of K ladder structure were measured for each isotopologue, identifying all three species as prolate symmetric tops. The data for each isotopologue were analyzed with a symmetric top Hamiltonian and rotational and centrifugal constants determined. In combination with previous measurements of Cl64ZnCH3, Cl66ZnCH3, and Cl68ZnCH3, an rm (2) structure was determined for this organozinc compound. The bond lengths in ClZnCH3 were calculated to be rCl-Zn = 2.0831(1) Å, rZn-C = 1.9085(1) Å, and rC-H = 1.1806(5) Å, considerably different from those established from crystal structures of related species ClZnCH2CH3 and ClZnEtTMEDA. The H[sbnd]C[sbnd]H bond angle was found to be 110.5° – slightly larger than that in methane. These data serve to benchmark future structure calculations of organozinc compounds, which are widely used in organic synthesis.
- Millimeter-wave spectroscopy
- Molecular structure
- Organozinc compounds
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry