Conformation and monolayer assembly structure of a pentiptycene-derived αω-alkanedithiol

The synthesis, conformation, and monolayer assembly structure of a pentiptycene-derived alpha,omega-alkanedithiol (1) are reported. The results of MM2 modeling, the scanning tunneling microscopy (STM.), and the surface plasmon resonance (SPR) suggest that 1 favors a folded conformation, corresponding to a looped monolayer assembly structure, on the Pt(lll) and Au(lll) surfaces. Nonetheless, the conformation of 1 in the crystals might be an extended form according to the crystal structure of an analogous compound 4. The relative interchain interactions and packing densities can account for the choice between a folded and an extended conformation for 1 in the condensed phases.