Changing gears to neutral in a polymorph of one-dimensional arrays of cogwheel-like pairs of molecular rotors

Identifier:  imarina:9282504

Handle: https://hdl.handle.net/20.500.11797/imarina9282504

Authors:  Bastien, G; Lemouchi, C; Allain, M; Wzietek, P; Rodríguez-Fortea, A; Canadell, E; Iliopoulos, K; Gindre, D; Chrysos, M; Batail, P

Abstract:
We report on a polymorph (2) of an amphidynamic crystal of molecular rods with two helical 1,4-bis(ethynyl)bicyclo[2.2.2]octane rotators where half of the rod-like molecules appear to be shifted with respect to their closest neighbours. This translation takes cogwheel-like pairs of rotators apart in the lattice in such a way that their motion becomes uncorrelated. This property is to be contrasted with the highly correlated motion found to govern the rotators in a recently-published polymorph 1 of the same material. As with polymorph 1, this motion is shown to take place independently of mutations in the handedness of the rotators and of the 'mutamer'-induced second harmonic generation. © 2014 The Royal Society of Chemistry.