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The interplay between experiment and theory: computational NMR spectroscopy of carbocations

2007; Elsevier BV; Linguagem: Inglês

10.1016/s0065-3160(07)42003-2

2162-5921

Hans‐Ullrich Siehl,

Advanced NMR Techniques and Applications

This chapter describes the recent applications of quantum chemical calculations of nuclear magnetic resonance (NMR) chemical shifts and spin–spin coupling constants in carbocation chemistry. Calculation of NMR parameters, such as chemical shift and spin–spin coupling constants has evolved into an important tool in carbocation chemistry as well as in related fields, such as silylenium ion and borane. Despite the successful prediction of chemical shifts for a great structural variety of carbocations some difficulties have been encountered for vinyl cations. Quantum chemical calculations of NMR parameters have provided detailed information on structures and stabilization modes of carbocations, and have provided deeper insights into intriguing questions and long-standing controversies in carbocation chemistry. The everlasting need for better experimental tools and theoretical methods to explore the field of carbocation chemistry had also a significant influence on the further development of ab initio methods for the calculation of NMR shielding and indirect spin–spin coupling constants. Carbocation chemistry thus, serves as a forerunner for a close integration of experimental and computational approaches in all areas of chemistry.