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Biological systems, including proteins, employ water-mediated supramolecular interactions to adopt specific conformations for their functions. However, current solid-state supramolecular materials are typically stiff and fail to capture the dynamic behaviors observed in proteins. Here, we present dynamic crystal-hydrates of aliphatic dipeptides with sequence-isomers of leucine (L) and isoleucine (I). These crystals exhibit shallow conformational energy landscapes, with various reconfigurable crystal nano-architectures accessible through small changes in relative humidity and temperature. Specifically, for LI crystals, as water content changes, the solid-state supramolecular architecture rapidly and reversibly transitions between perpendicular and parallel honeycomb nano-architectures, as well as layered van der Waals structures, leading to significant and distinct variations in mechanical and photophysical properties. Our findings demonstrate the potential of leveraging aliphatic hydrophobic domains inspired by protein architectures to create dynamic solid-state materials with context-adaptive properties. 

MMP-responsive nanomaterials can be used to control and amplify the spatial and temporal effects of anti-cancer treatments. This review focuses on the design strategies that can regulate and optimize enzyme specificity, access, and response. 

Tuning solubility and mechanical activation alters the stereoselectivity of the [2 + 2] photochemical cycloaddition of acenaphthylene. Photomechanochemical conditions produce the syn cyclobutane, whereas the solid-state reaction in the absence of mechanical activation provides the anti . When the photochemical dimerization occurs in a solubilizing organic solvent, there is no selectivity. Dimerization in H 2 O, in which acenaphthylene is insoluble, provides the anti product. DFT calculations reveal that insoluble and solid-state reactions proceed via a covalently bonded excimer, which drives anti selectivity. Alternatively, the noncovalently bound syn conformer is more mechanosusceptible than the anti , meaning it experiences greater destabilization, thereby producing the syn product under photomechanochemical conditions. Cyclobutanes are important components of biologically active natural products and organic materials, and we demonstrate stereoselective methods for obtaining syn or anti cyclobutanes under mild conditions and without organic solvents. With this work, we validate photomechanochemistry as a viable new direction for the preparation of complex organic scaffolds.