title: Study of the fluoro- and chlorodimethylbutyl cations.
abstract: A comparative study of the 2,3-dimethyl-3-fluoro-2-butyl cation and its chloro analog was carried out by the ab initio/GIAO-CCSD(T) (gauge invariant atomic orbital-coupled cluster with single, double, and perturbative triple excitation) method. The structures and (13)C NMR chemical shifts of the cations were calculated at the GIAO-CCSD(T)/tzp/dz//MP2/cc-pVTZ level. Bridged fluoronium ion 1, carbenium ion 2, and fluorocarbenium ion 3 were found to be minima on the potential energy surface. Bridged fluoronium ion 1, although a minimum on the potential energy surface, is 12.8 kcal/mol less stable than the open chain fluorobutyl cation 3. In contrast to the fluorinated ion, bridged chloronium ion 5 was found to be the lowest energy minimum being 10.6 kcal/mol more stable than ion 6 and 7.4 kcal/mol more stable than ion 7.
authors: Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California, Los Angeles, CA 90089-1661, USA. olah@usc.edu
authors: George A
authors: GA
authors: Olah
authors: G K Surya
authors: GK
authors: Prakash
authors: Golam
authors: G
authors: Rasul
keywords: carbocations; computational studies
references: J Am Chem Soc. 2004 Jul 7;126(26):8189-96
references: 15225060
references: J Am Chem Soc. 2006 Aug 2;128(30):9676-82
references: 16866520