Surface alignment of the N-octadecylazatriquinacenium cation as determined by sum frequency generation on the surface of H2O and D2O

Chemistry of the Heterotriquinanes and Heterotriquinacenes

Triquinanes are tricyclic hydrocarbons that have fused cyclopentane rings. Although there are linear and angular triquinanes that are doubly fused, this Account focuses exclusively on the ‘triquinacane’, or triply fused structure with a heteroatom (nitrogen or oxygen) on the C 3v symmetry axis. Azatriquinane- and oxatriquinane-based species tend to show remarkable and often unexpected chemistry, and have variously comprised the most basic trialkyl amine, a superbasic proton chelate, trigonal pyramidal ligand platforms, novel calixiform hosts, aromatic hemispheres of hetero-C20 fullerenes, cocrystallizing agents for eliminating rotational disorder in fullerene crystals, the first water-stable, chromatographable trialkyloxonium species, the first isolable allylic oxonium species, world-record C–O bond lengths, rapid SN2 reaction at a tertiary center, and R4O2+ (oxadionium) species.

1 Introduction

2 Azatriquinane

3 Azatriquinacene

4 Aromatic Azatriquinacene-Based Systems

5 Oxatriquinane

6 Tetravalent Oxygen

7 Oxatriquinacene

8 The Future