Light-Driven Molecular Motors: Imines as Four-Step or Two-Step Unidirectional Rotors

Chiral <i>N</i>-alkyl imines undergo unidirectional rotation induced by light and heat, thus providing a new class of molecular motors. Depending on the conformational flexibility of the stator part (the carbonyl residue) and the nitrogen inversion barrier of the rotor part (the amine residue) in the molecule, the operation mode of the motor can be controlled as either a four- or a two-step cycling motion of the rotor part

Silicon Carbamates by CO₂ Fixation: Brønsted Acid Labile Precursor of a Lewis Superacid

Treatment of Lewis superacidic Si(catCl)2(MeCN)2 and tetramethylpiperidine (TMP) or hexahydropyrimidopyrimidine (hppH) with CO2 leads to an FLP-type formation of silicon carbamates. The employed Lewis base determines the hapticity at silicon and the reactivity of the carbamates in subsequent transformations. Upon treatment with a Brønsted acid, the carbamates liberate CO2 and reactivate the Lewis superacidic behavior of 1. Hence, the CO2 fixation products serve as valuable surrogates for Si(catCl)2 that circumvent its insolubility in organic solvents. Quantum chemical computations support all of the experimental observations

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<i>N</i>-alkyl α-bisimines were employed as main-chain functional groups in acyclic diene metathesis (ADMET)-polymers, conferring dual responsiveness for the controlled switching of the polymeric particle shape with light and metal ions. Photochemical <i>Z/E</i>-isomerization leads to a significant and reversible change in hydrodynamic volume, thus introducing simple imines as novel photoswitches for light-responsive materials. Mild imine-directed CH activation by Pd­(OAc)₂ is demonstrated as a new single-chain nanoparticle (SCNP) folding process, enabling a controlled atom- and step-economic SCNP synthesis. The combination of light- and metallo-responsiveness in the same polymer provides the ability for orthogonal switching, a valuable tool for advanced functional material design