Solution Structures of Pyrophthalones, I Structure and Conformation of 1,3-Indandionato-2(2-pyridinium)-betaïn — a ¹H/¹³C NMR Approach

Abstract

<jats:title>Abstract</jats:title><jats:p>The complete analysis of the <jats:sup>1</jats:sup>H/<jats:sup>13</jats:sup> C NMR spectra of α-Pyrophthalone and related compounds demonstrates that the earlier static planar description of the molecules is invalid for polar sol-vents, and here the stability of any intramolecular hydrogen bond is small.</jats:p>