Solvent-dependent reactivity of azo-BF switches.

Azo-BF complexes are visible and near-infrared (NIR) light-activated photoswitches showcasing versatility in applications ranging from energy storage to three-dimensional displays. While highly appealing as molecular switches, factors that affect their photophysical properties and solution-state reactivity still need to be teased out. In this paper, we present the synthesis and characterization of two azo-BF analogues (1 and 2), each modified with structurally distinct dimethylamine-substituted naphthalene moieties.

A molecular anion pump.

Pumping ions against a concentration gradient through protein-based transporters is a cornerstone of numerous biological processes. Mimicking this function by using artificial receptors remains a daunting challenge, mainly because of the difficulties in balancing between the requirement for high binding affinities and precise and on-demand ion capture and release properties. We report a trimeric hydrazone photoswitch-based receptor that converts light energy into work by actively transporting chloride anion against a gradient through a dichloromethane liquid membrane, functioning as a molecular pump.

Metal and Proton Relay-Controlled Hierarchical Multistep Switching Cascade.

Transition metals play an important role in many biological processes including cellular regulation and signal transduction. Emulating such processes on the molecular level, while challenging, can help us learn how to manipulate intermolecular communication, an important requirement for the development of solution-based molecular machines. In this work, we demonstrate a transition metal-based artificial multistep switching cascade that exhibits intrinsic hierarchical level control.

Photon Energy Storage in Strained Cyclic Hydrazones: Emerging Molecular Solar Thermal Energy Storage Compounds.

The generally small Gibbs free energy difference between the and isomers of hydrazone photoswitches has so far precluded their use in photon energy storing applications. Here, we report on a series of cyclic and acyclic hydrazones, which possess varied degrees of ring strain and, hence, stability of isomers. The photoinduced isomerization and concurrent phase transition of the cyclic hydrazones from a crystalline to a liquid phase result in the storage of a large quantity of energy, comparable to that of azobenzene derivatives.

Asymmetric total synthesis of yuzurimine-type Daphniphyllum alkaloid (+)-caldaphnidine J.

Ever since Hirata's report of yuzurimine in 1966, nearly fifty yuzurimine-type alkaloids have been isolated, which formed the largest subfamily of the Daphniphyllum alkaloids. Despite extensive synthetic studies towards this synthetically challenging and biologically intriguing family, no total synthesis of any yuzurimine-type alkaloids has been achieved to date. Here, the first enantioselective total synthesis of (+)-caldaphnidine J, a highly complex yuzurimine-type Daphniphyllum alkaloid, is described.