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Published on: June 23, 2019
Microwave spectrum, structural parameters, and quadrupole coupling for 1,2-dihydro-1,2-azaborine
Adam M Daly1, Chakree Tanjaroon, Adam J V Marwitz
1Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, USA.
Journal of the American Chemical Society
|March 31, 2010
Summary
The first microwave spectrum of 1,2-dihydro-1,2-azaborine reveals its planar structure. This study precisely determined molecular parameters and electron distribution in this heterocyclic compound.
Area of Science:
- Physical Chemistry
- Molecular Spectroscopy
- Quantum Chemistry
Background:
- 1,2-dihydro-1,2-azaborine is a heterocyclic compound containing boron and nitrogen.
- Understanding its molecular structure and electronic properties is crucial for various chemical applications.
Purpose of the Study:
- To measure the microwave spectrum of 1,2-dihydro-1,2-azaborine and its isotopomers.
- To accurately determine the molecule's structural parameters, including bond lengths and angles.
- To investigate the electronic structure through nuclear quadrupole coupling constants.
Main Methods:
- Pulsed beam Fourier transform microwave spectroscopy was employed to obtain high-resolution spectra.
- Ab initio calculations were performed to complement experimental data.
- Least-squares fitting analysis was used to determine structural parameters.
Main Results:
- Accurate rotational constants and quadrupole coupling strengths for three isotopomers were obtained.
- The planar structure of 1,2-dihydro-1,2-azaborine was confirmed by a near-zero positive inertial defect.
- Experimental bond lengths (R(B-N) = 1.45(3) Å, R(B-C) = 1.51(1) Å, R(N-C) = 1.37(3) Å) and interbond angles were determined.
- Valence p-electron occupancy for boron and nitrogen was calculated.
Conclusions:
- The study provides the first comprehensive microwave spectroscopic analysis of 1,2-dihydro-1,2-azaborine.
- The experimental data confirms the planarity and provides precise structural and electronic information.
- The results agree well with high-level theoretical calculations.
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