According to our present knowledge, the spontaneous resolution of racemic mixtures of chiral molecules or chiral conformers of achiral molecules into macroscopic chiral superstructures requires the confinement of these molecules in a crystal lattice, on surfaces or in other well-ordered assemblies. Herein we provide the first experimental evidence that mirror-symmetry breaking can also take place at a liquid-liquid phase transition in isotropic liquids of achiral molecules, even at relatively high temperatures around 200 °C. It is proposed that cooperative segregation of enantiomorphic molecular conformations gives rise to a conglomerate of two chiral and immiscible liquids. In these liquid conglomerates a strong chiral amplification was observed, which led to degeneracy from a stochastic distribution and eventually provided uniform chirality. We anticipate that this work will contribute to the understanding of symmetry breaking in soft matter and provide a new tool for the identification of chirality traces, and possibly affect the discussion of the emergence of chirality in prebiotic systems.

Achiral multi-chain benzil derivatives provide a missing link between mirror symmetry breaking phenomena in fluid systems of polycatenar and bent-core liquid crystals.

Achiral compounds with an alicyclic apex form a chiral cubic phase either for a specific ring-size or by mixing of small- and large-ring compounds.

Bicontinuous cubic liquid crystalline phases of π-conjugated molecules, representing self-assembled 3D-ordered interpenetrating networks with cubic symmetry, are receiving increasing attention due to their capacity for charge transport in all three dimensions and their inherent spontaneous helicity. Herein, a robust general design concept for creating bicontinuous cubic phases is reported. It is based on a nonsymmetric-substituted π-conjugated 5,5′-diphenyl-2,2′-bithiophene platform with one end containing three outfanning flexible chains and with a range of substituents at the other end (the apex). The cubic phases are stable over broad temperature ranges, often down to ambient temperature, and tolerate a wide range of apex substitution patterns, allowing structural diversity and tailoring of the cubic phase type and application-relevant properties. With an increasing number and size of apex substituents, a sequence of three different modes of cubic self-assembly is observed, following an increasing helical twist. Thus, two ranges of the achiral double network Ia3d phase range can be distinguished, a long pitch and a short pitch, with the chiral triple network I23 cubic phase in the intermediate pitch range. The findings provide a new prospect for the directed design of cubic phase-forming functional materials based on spontaneously formed helical network liquid crystals with tunable application specific properties.

In article number 2004353, Goran Ungar, Carsten Tschierske, and co‐workers present a general design concept of bicontinuous cubic liquid crystals consisting of helical networks that are stable over a broad temperature range. Increasingly bulky substituents cause increasing helical twist between the three‐chain 2,2′‐bithiophene based molecular rods, resulting in a sequence of three distinct phases: two ranges of achiral double network (Iatrue3¯d) separated by a range of spontaneously chiral triple network (I23).

Spontaneousd evelopment of chirality in systems composed of achiral molecules is important for new routes to asymmetricsynthesis, chiral superstructures and materials, as well as for the understanding of the mechanisms of emergence of prebiotic chirality.H erein, it is shown that the 4,4'diphenylbenzil unit is au niversal transiently chiral bent building block for the design of multi-chained (polycatenar) rod-like molecules capable of forming aw idev ariety of helically twisted network structures in the liquid,t he liquid crystalline (LC) and the crystalline state. Single polar substituents at the apex of tricatenar molecules support the formation of the achiral (racemic) cubic double network phase with Ia3 d symmetry and relatively small twist along the networks. The combination of an alkyl chain with fluorine substitution leads to the homogeneously chiral triple network phase with I23 space group, and in addition, provides am irror symmetry broken liquid.R eplacing Fb yC lo rB rf urtheri ncreasest he twist,l eading to as hort pitch doubleg yroid Ia3 d phase, which is achiral again. The effects of the structural variations on the network structures, either leading to achiral phases or chiral conglomerates are analyzed.

molecules in soft self-organized supramolecular systems. [1,2] Extended π-conjugated systems are also of significant interest for application as charge carrier in organic semiconductors, [3] luminescent materials (e.g., AIEgens), [4] and for circular polarized emission in helical assemblies. [5] Therefore, tuning the organization of these π-conjugated rods in soft matter systems is fundamental and requires the understanding of their general design rules. Liquid crystals (LCs) are of great interest as stimuli-responsive and switchable optical materials in displays, photo nics [6] and in sensor applications. [7,8] Rod-like π-conjugated molecules with multiple end-chains, the so-called polycatenar molecules, have received significant interests as they provide a huge variety of different LC phases ranging from lamellar (smectic, Sm) via bicontinuous cubic (Cub bi) to columnar (Col) [9-11] and even micellar cubic phases. [3] This observation has contributed to the recognition of the importance of nano-segregation for LC phase formation and demonstrated the similarity of the fundamental self-assembly principles in lyotropic systems formed by amphiphiles, in LC phases and in the solid state morphologies of block copolymers. [12,13] Among the self-assembled structures of polycatenar molecules, the Cub bi phases [14,15] received special attention because of their potential for applications, as for example in 3D conducting [16] and photonic materials, [17] being the result of their interwoven net-* ]) as well. This work establishes rules for controlling the self-assembly of functional π-conjugated rods in soft matter and fluids.