Rotational Spectra and Conformational Structures of1-Phenyl-2-Propanol, Methamphetamine, and 1-Phenyl-2-Propanone

Published

December 14, 2006

Author(s)

M J. Tubergen, R L. Lavrich, David F. Plusquellic, R D. Suenram

Abstract

Microwave spectra have been recorded for 1-phenyl-2-propanol, methamphetamine, and 1-phenyl-2-propanone in the range 11 GHz to 24 GHz using a Fourier-transform microwave spectrometer. Only one spectrum from a single conformational isomer was observed for each species. The rotational transitions in the spectrum of the 1-phenyl-2-propanone were split into separate transitions arising from the A- and E-torsional levels of the methyl rotor. The fit of the E-state transitions to a high-barrier internal rotation Hamiltonian determines V3 = 238 (1) cm-1 and rotor-axis angles of ?a = 87.7(5) , ?b = 50.0(5) , and ?c = 40.0(5) . Ab initio optimizations (MP2/6-31G*) and single point calculations (MP2/6-311++G**) were used to model the structures of 1-phenyl-2-propanol, methamphetamine, and 1-phenyl-2-propanone. Moments of inertia, derived from the model structures, were used to assign the spectra to the lowest energy conformation of each species. A series of MP2/6-31G* partial optimizations along the internal rotation pathway was used to estimate the barrier to methyl rotation to be 355 cm-1 for 1-phenyl-2-propanone.

Citation

Journal of Physical Chemistry A

Volume

110

Issue

49

Pub Type

Journals

Keywords

biosystems and health, conformational structure, illicit drug, molecular structure

Citation

Tubergen, M. , Lavrich, R. , Plusquellic, D. and Suenram, R. (2006), Rotational Spectra and Conformational Structures of1-Phenyl-2-Propanol, Methamphetamine, and 1-Phenyl-2-Propanone, Journal of Physical Chemistry A (Accessed April 19, 2024)