Structure and reactivity of hydrocarbon radical cations

Olaf Wiest, Jonas Oxgaard and Nicolas J. Saettel 

Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA 

These developments have in turn renewed the interest in understanding the structure and reactivity of radical cations. Modern computational chemistry methods, especially density functional methods, as well as the continued exponential increase in hardware performance provided improved tools for a detailed analysis of these interesting species. At the same time, the unique problems of the computational treatment of radical cations as well as the direct and indirect observation of these short-lived species continue to pose new challenges for the development of new theoretical and experimental methods. 

ADVANCES IN PHYSICAL ORGANIC CHEMISTRY VOLUME 38 ISSN 0065-3160 DOI 10.10I6/S0065-3160(03)38002-5 

The purpose of this review is to discuss some recent computational studies of radical cations in the context of qualitative concepts of classical physical organic chemistry. In particular, we will demonstrate how such basic, well-understood concepts such as conjugation and electronic state or even more fundamental notions of structure, bonding, and mechanism can lead to new and interesting effects in radical cation chemistry, which are quite different than what is usually expected in the chemistry of neutral compounds. We will also discuss how these effects need to be taken into consideration to understand the chemistry of radical cations. This relatively broad scope means that this review will necessarily be limited to a focused discussion rather than a comprehensive review of the different aspects of radical cation chemistry. Thus, we will concentrate on computational results from our own laboratory, and will discuss experimental data only in the context of the calculational data. A number of recent reviews5 and book chapters6 provide much more detail on aspects that cannot be covered in this limited contribution. 

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Structure, determination of organic reactivity, 35, 67 Structure and mechanism, in curbene chemistry, 7, 153 Structure and mechanism, in organic electrochemistry, 12, 1 Structure and reactivity of carbencs having aryl substitutents, 22, 311 Structure and reactivity of hydrocarbon radical cations, 38, 87 Structure of electronically excited molecules, 1, 365... 

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