Biased Bowl-Direction of Monofluorosumanene in the Solid State

A new curved pi-conjugated molecule 1-fluorosumanene (1) was designed and synthesized that possesses one fluorine atom on the benzylic carbon of sumanene. This compound can exhibit bowl inversion in solution, leading to the formation of two diastereomers, 1(endo) and 1(exo), with different dipole moments. Experimental and theoretical investigation revealed an energetical relationship among 1(exo), 1(endo), and solvent to realize the various endo:exo ratios in the single crystals of 1 depending on the crystallization solvent. Significantly, the molecular dynamics (MD) simulations revealed that 1(exo) positively worked for the elongation of the stacking structure and the final endo:exo ratio was affected by the relative stability difference between 1(endo) and 1(exo) derived by solvation. Such an arrangeable endo:exo ratio of 1 realized the preparation of unique materials showing a different dielectric response from the same molecule 1 just by changing the crystallization solvent.