Intramolecular non‐bonded interactions and 13C NMR chemical shifts

Abstract

AbstractThe recently proposed empirical analysis of β‐ and γ‐SCS in terms of the local non‐bonded van der Waals and electrostatic intramolecular interaction energies is extended to an application for the 13C NMR chemical shifts (δ) of primary, secondary and tertiary carbon atoms of numerous classes of unsubstituted hydrocarbons of varied degrees of strain. A correspondence is established between the (Evdw)M local non‐bonded interactions of tertiary carbon atoms and the theoretically evaluated Op shielding constants, and also between δ(13C‐prim); δ(13C‐sec) and the non‐bonded part of the molecular potential which describes binding energies in ESCA. In addition, it is shown that the δ(13C) values of primary, secondary or tertiary carbon atoms at positions β and γ to an OH substituent, in a variety of mono‐ and di‐hydroxy aliphatic molecules, are related to the local Evdw and Echarge interaction energies.