Helical superstructures of a C < inf > 2 < /inf > -symmetric molecule exhibiting strong second harmonic generation in the solid-state

Abstract

The crystallization solvent exerts a critical control of the nonlinear optical properties of helical superstructures in molecular crystals based on N,N′-bis(4-nitrophenyl)- (1R,2R)-diaminocyclohexane. While crystallization from ethyl acetate resulted in mutually orthogonal helices with different handedness, crystallization from ethyl acetate/hexane or acetyl acetone/hexane resulted in the formation of helical motifs (see picture) of a single-handedness oriented in one direction. The latter showed a strong solid-state second harmonic generation capability.