Computational and Experimental Studies into the Conformations of a Triptycene-Based Ditopic Ligand

We present a combined computational and experimental study of the possible conformations adopted by a ditopic Schiff base ligand based on triptycene. We have performed DFT calculations on a Y-shaped Schiff base ligand derived from the condensation of 2,6-diaminotriptycene and 2 hydroxybenzaldehyde to obtain the relative energies of their conformers anti-s-cis, syn and anti-s-trans. Since these conformations are practically isoenergetic, interconversions of conformers proceed by rotation about C-N single bonds. NMR spectroscopy shows the presence in solution of the syn conformer, which is stable at room temperature on the NMR time scale.