The conformational behaviour of thiacalix[4]arenes: the pinched cone–pinched cone transition

摘要

This work is focused on the dynamics and thermodynamics of the pinched cone ↔ pinched cone interconversionnof calix[4]arenes. The behaviour of methylene bridged non-substituted tetraalkoxycalix[4]arene and itsntetraalkoxythiacalix[4]arene analogue is compared. Energetic and structural changes during this interconversionnhave been closely studied by HF and DFT quantum chemistry methods in combination with temperature -dependentn1H NMR spectroscopy. The most important stationary points—minima and transition states—on the potentialnenergy surface have been identified and their symmetry and other structural properties have been determined.