NON-BENZENOID AROMATIC COMPOUNDS AND THE CONCEPT OF AROMATICITY

Abstract

CONTENTS I. Introduction 129 II. Structure of aromatic compounds and nature of aromaticity 130 III. The cyclopentadienide anion 132 IV. The tropylium cation 134 V. The cyclopropenylium cation 139 VI. Azulenes 140 VII. Cyclobutadiene 142 VIII. Cyclooctatetraene 145 IX. Pentalene and heptalene 145 X. Polycyclic systems. Generalised Huckel rule 147 XI. Macrocyclic aromatic systems 150 XII. Aromatic complexes of metals 152 XIII. Aromatic heterocycles 152 XIV. Inorganic aromatic compounds 154 XV. Conclusion 156