The use of the triptycene framework for observing O⋯C=O molecular interactions

The triptycene skeleton has been used to measure (1,5) interactions between aldehyde groups, placed at both sp³ centres, and hydroxy or methoxy groups, placed at the respective ortho position on a benzene ring; HO⋯CHO interactions of 2.621–2.624 Å and MeO⋯CHO interactions of 2.528–2.584 Å were observed with the O⋯C vector making angles of 105.3–133.7° with the carbonyl bond. The lack of a competing conjugation with the framework for the electrophilic group is a favourable factor compared to the use of peri-naphthalene systems