Molecular Bending: An Important Factor Affecting the Packing of Self-Assembled Monolayers of Triptycene-Based Molecular Rods on a (111) Gold Surface

The present study has identified molecular bending as an important factor that has a profound effect on the self-assembly of originally rod-shaped organic molecules on a (111) gold surface. This was demonstrated on three specifically designed rigid molecular rods carrying archetypal anchoring groups (pyridyl units and thiols) on one terminus. These rods were used to prepare corresponding self-assembled monolayers (SAMs), and a combination of various analytical techniques revealed that originally straight molecular rods that were bent once adsorbed on a metallic surface, acquiring a characteristic “J-shape”. Extensive density functional theory calculations, including in silico reconstruction of such SAMs on (111) gold, clearly confirmed experimental observations.