A Chemical Reaction Network Drives Complex Population Dynamics in Oscillating Self-Reproducing Vesicles.

We report chemically fueled oscillations of vesicles. The population cycling of vesicles is driven by their self-reproduction and collapse within a biphasic reaction network involving the interplay of molecular and supramolecular events. We studied the oscillations on the molecular and supramolecular scales and tracked vesicle populations in time by interferometric scattering microscopy and dynamic light scattering. Complex supramolecular events were observed during oscillations─including vesicle reproduction, growth, and decomposition─and differences in the number, size, and mass of aggregates can often be observed within and between pulses. This system's dynamic behavior is reminiscent of a reproductive cycle in living cells.

From autocatalysis to survival of the fittest in self-reproducing lipid systems.

Studying autocatalysis - in which molecules catalyse their own formation - might help to explain the emergence of chemical systems that exhibit traits normally associated with biology. When coupled to other processes, autocatalysis can lead to complex systems-level behaviour in apparently simple mixtures. Lipids are an important class of chemicals that appear simple in isolation, but collectively show complex supramolecular and mesoscale dynamics. Here we discuss autocatalytic lipids as a source of extraordinary behaviour such as primitive chemical evolution, chemotaxis, temporally controllable materials and even as supramolecular catalysts for continuous synthesis. We survey the literature since the first examples of lipid autocatalysis and highlight state-of-the-art synthetic systems that emulate life, displaying behaviour such as metabolism and homeostasis, with special consideration for generating structural complexity and out-of-equilibrium models of life. Autocatalytic lipid systems have enormous potential for building complexity from simple components, and connections between physical effects and molecular reactivity are only just beginning to be discovered.

An autonomously oscillating supramolecular self-replicator.

A key goal of chemistry is to develop synthetic systems that mimic biology, such as self-assembling, self-replicating models of minimal life forms. Oscillations are often observed in complex biological networks, but oscillating, self-replicating species are unknown, and how to control autonomous supramolecular-level oscillating systems is also not yet established. Here we show how a population of self-assembling self-replicators can autonomously oscillate, so that simple micellar species repeatedly appear and disappear in time. The interplay of molecular and supramolecular events is key to observing oscillations: the repeated formation and disappearance of compartments is connected to a reaction network where molecular-level species are formed and broken down. The dynamic behaviour of our system across different length scales offers the opportunities for mass transport, as we demonstrate via reversible dye uptake. We believe these findings will inspire new biomimetic systems and may unlock nanotechnology systems such as (supra)molecular pumps, where compartment formation is controlled in time and space.

Selection between Competing Self-Reproducing Lipids: Succession and Dynamic Activation.

Models of chemical evolution are central to advancing origins of life research. To design more lifelike systems, we must expand our understanding of molecular selection mechanisms. Here, we show two selection modes that produce evolving populations of self-reproducing species, formed through thiol-disulfide exchange. Competition between thiol precursors can give clear succession patterns based on steric factors, an intrinsic property. A separate, emergent selection mechanism-dynamic activating metathesis-was found when exploring competing disulfide precursors. These experiments reveal that additional species generated in the mixture open up alternative reaction pathways to form self-reproducing products. Thus, increased compositional complexity provides certain species with a unique competitive advantage at the expense of others.

Enantioselective reduction of N-alkyl ketimines with frustrated Lewis pair catalysis using chiral borenium ions.

Enantioselective reduction of ketimines was demonstrated using chiral N-heterocyclic carbene (NHC)-stabilised borenium ions in frustrated Lewis pair catalysis. High levels of enantioselectivity were achieved for substrates featuring secondary N-alkyl substituents. Comparative reactivity and mechanistic studies identify key determinants required to achieve useful enantioselectivity and represent a step forward in the further development of enantioselective FLP methodologies.

Kinetic Treatments for Catalyst Activation and Deactivation Processes based on Variable Time Normalization Analysis.

Progress reaction profiles are affected by both catalyst activation and deactivation processes occurring alongside the main reaction. These processes complicate the kinetic analysis of reactions, often directing researchers toward incorrect conclusions. We report the application of two kinetic treatments, based on variable time normalization analysis, to reactions involving catalyst activation and deactivation processes. The first kinetic treatment allows the removal of induction periods or the effect of rate perturbations associated with catalyst deactivation from kinetic profiles when the quantity of active catalyst can be measured. The second treatment allows the estimation of the activation or deactivation profile of the catalyst when the order of the reactants for the main reaction is known. Both treatments facilitate kinetic analysis of reactions suffering catalyst activation or deactivation processes.