ChemInform Abstract: 1,6‐Disubstituted Triptycenes

Abstract

Publisher Summary This chapter discusses the chemical properties of 1,6-disubstituted triptycenes. The 1,6-, or bridgehead, carbon atoms in the symmetric molecule can theoretically be substituted with any elements capable of tetrahedral coordination, the most likely candidates being in Groups III, IV, V, and VI of the periodic table. Special techniques must be devised for the other triptycenes. The simple method of direct synthesis in a heated, sealed tube is applicable to the more thermally stable triptycenes. Transmetallations with perfluoro- and perchloro–phenylenemercury give much better yields of the very thermally stable perhalotriptycenes. Dreiding models depict triptycenes as totally rigid systems, but several 1- and mixed l,6-derivatives (as well as triptycene) show considerable distortion from their expected threefold symmetry. Triptycene is very stable under electron impact and both the doubly and triply charged molecular ions are present in the mass spectrum. The triptycene skeleton is exceedingly stable. Perfluorodistibatriptycene is unaffected by cold, concentrated nitric acid but dissolves with oxidation on boiling. Several of the Group V triptycenes should prove to be useful ligands toward transition metals because the organic groups are effectively tied back and so partially relieve steric requirements at the donor atom.