Ab initio/DFT/GIAO-CCSD(T) calculational study of the t-butyl cation: comparison of experimental data with structures, energetics, IR vibrational frequencies, and 13C NMR chemical shifts indicating preferred C(s) conformation

Golam Rasul; Jonathan L Chen; G K Surya Prakash; George A Olah

doi:10.1021/jp903002z

Ab initio/DFT/GIAO-CCSD(T) calculational study of the t-butyl cation: comparison of experimental data with structures, energetics, IR vibrational frequencies, and 13C NMR chemical shifts indicating preferred C(s) conformation

J Phys Chem A. 2009 Jun 18;113(24):6795-9. doi: 10.1021/jp903002z.

Authors

Golam Rasul¹, Jonathan L Chen, G K Surya Prakash, George A Olah

Affiliation

¹ Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, University Park, Los Angeles, California 90089-1661, USA.

PMID: 19476321
DOI: 10.1021/jp903002z

Abstract

The C(s) conformation of the tert-butyl cation 3 was established to be the preferred global energy minimum using a combination of ab initio, DFT, and CCSD(T) methodology with correlation-consistent basis sets. The potential energy surface of methyl rotation involving the C(3v), C(s), and C(3h) forms, however, in accord with previous studies, is quite flat. The computed IR absorptions of 3 indicate that it has the greatest degree of electron donation from C-H bonds into the C(+)-C bonds. The experimental (13)C NMR chemical shifts also agree very well with the experimental data.

Publication types

Comparative Study

MeSH terms

Butanes / chemistry*
Carbon Isotopes
Cations / chemistry
Computer Simulation*
Magnetic Resonance Spectroscopy / standards
Models, Chemical*
Molecular Structure
Quantum Theory*
Reference Standards
Spectrophotometry, Infrared
Thermodynamics*
Vibration

Substances

Butanes
Carbon Isotopes
Cations