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.

Stochastic achiral symmetry breaking in soft matter systems, leading to conglomerates of macroscopically chiral domains (so-called dark conglomerate ¼ DC phases) is of contemporary interest from a fundamental scientific point of view as well as for numerous potential applications in chirality sensing and noncentrosymmetric materials. Herein we report the synthesis and investigation of first azobenzene containing bent-core mesogens derived from 4-methylresorcinol forming DC phases with a new structure, distinct from the known fluid sponge-like distorted smectic phases as well as from the helical nano-filament phases (HNF phases, B 4 phases). The effects of chain length and other structural modifications on achiral symmetry breaking were investigated. Homologues with relatively short alkyl chains form achiral intercalated lamellar LC phases (B 6 phases), but on increasing the chains, these are replaced by the chiral and optically isotropic DC phases. Compounds with the longest alkyl chains form low birefringent crystalline conglomerates which represent less distorted versions of the optically isotropic DC-phases. Introducing additional peripheral substituents at both outer rings removes the DC phases. The DC phases were also removed and replaced by modulated smectic phases if the azo groups were replaced by ester units, showing that azo groups favour DC phase formation with new nanostructures, distinct from the previously known types.

New 4-bromoresorcinol based bent-core molecules with peripheral fluoro substituted azobenzene wings have been synthesized and the liquid crystalline self-assembly was investigated by differential scanning calorimetry (DSC), optical polarizing microscopy (POM), electro-optic studies and X-ray diffraction (XRD). A new type of optically isotropic mesophase composed of chiral domains with opposite handedness (dark conglomerate phases, DC phases) is observed, which for some homologues with medium alkyl chain length is stable down to ambient temperature. It is proposed that these DC phases are formed by helical twisted nano-domains of limited size and composed of the crystallized aromatic cores which are separated by the disordered alkyl chains. This structure is distinct from the previously known soft helical nano-filament phases (HNF phases, B4 phases) formed by extended crystalline nano-filaments and also distinct from the fluid sponge phases composed of deformed fluid layers. Comparison with related bent-core molecules having H, F, Cl, I, CH3 and CN groups in the 4-position at the resorcinol core, either with or without additional peripheral fluorines, provided information about the effects of these substituents on the tendency to form DC phases. Based on these relationships and by comparison with the minimum energy conformations obtained by DFT calculations a hypothesis is provided for the formation of DC phases depending on the molecular structure.

We have investigated and exploited a new photochemical route to hydrated electrons, which are among the strongest reductants known and can even be used for direct carbon dioxide and nitrogen fixation.Our electron precursor is the ascorbate dianion, which we photoionize with a 355 nm laser. The method is instrumentally much simpler and far less accompanied by health and safety issues than is pulse radiolysis. Advantages over other photoionizable substrates or systems comprise the favourably long operating wavelength, at which many additives do not absorb anymore; the low price and nonexisting biohazards of this naturally occurring electron precursor; and the lack of visible absorption as well as the nonreactivity of the ionization by-product, the ascorbate radical, which greatly simplifies the mechanistic and kinetic studies of subsequent reactions. To illustrate the usefulness of this electron source, we have prepared a number of radical anions (through scavenging the electrons) including several that are inaccessible by the usual photochemical route for mechanistic or thermodynamic reasons, obtained their calibrated absorption spectra, and in one case investigated their green-light photochemistry. As proof of its applicability to environmental remediation, we have successfully utilized this electron generator to detoxify a model compound for halogenated organic waste. † Electronic supplementary information (ESI) available: Ground-state spectra of pertinent compounds. See

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