Racemic mixtures of aminomethylenehelicene (P)- and (M)-pentamers exhibited deterministic and stochastic chiral symmetry breaking during hetero-double-helix formation and self-assembly in solution. Heating a 50:50 mixture of (P)- and (M)-pentamers at 90 °C, and then cooling the mixture to 70 °C resulted in hetero-double-helix formation; a Cotton effect with negative Δε at λ=315 nm appeared. Chiral self-assembly occurred when the mixture was cooled to 25 °C. A strong tendency of deterministic chiral symmetry breaking appeared at the molecular and self-assembled levels, which was indicated by the negative Δε at λ=315 nm that appeared in most cases in repeated experiments. Mixtures containing 60:40 and 40:60 (P)-/(M)-pentamers also self-assembled with the same chirality. When a homo-double-helix (P)-/(M)-pentamer and a random coil (M)-/(P)-pentamer were mixed, the chiral self-assembly formed stochastically, and heating and cooling resulted in deterministic chiral symmetry breaking.

Self-catalytic reactions are chemical phenomena, in which a product catalyzes the reactions of substrates further to yield products. A significant amplification of product concentration occurs during the reactions in a dilute solution, which exhibit notable properties such as sigmoidal kinetics, seeding effects, and thermal hysteresis. Chemical systems involving two competitive self-catalytic reactions can be considered, in which the competitive formation of two products occurs, which is affected by environmental changes, subtle perturbations, and fluctuations, and notable chemical phenomena appear such as formation of different structures in response to slow/fast temperature changes, chiral symmetry breaking, shortcut in reaction time, homogeneous–heterogeneous transitions, and mechanical responses. Studies on such chemical systems provide understanding on biological systems and can also be extended to the development of novel functional materials.

Oxymethylenehelicene (P)- and (M)-oligomers up to a nonamer were synthesized by a building block method. The oligomers formed dimeric homoaggregates in trifluoromethylbenzene. A mixture of the pseudoenantiomeric (P)-pentamer and (M)-hexamer formed a heteroaggregate, which self-assembled into one-dimensional fibril films at the liquid-solid interface. Discontinuous heterogeneous nucleation occurred, which involved the formation of particles that were 50 nm in diameter and subsequent fibril growth from these particles. The fibril film was formed on the solid surface and the molecules remained dissociated in solution. The fibril film formation was affected by seeding and the solid surface materials.

1 : 1 mixtures of aminomethylenehelicene (P)-tetramer and (M)-pentamer with terminal C16 alkyl groups in fluorobenzene showed structural changes between hetero-double-helices B and C and random-coils 2A.