Thermally Induced Intra‐Carboxyl Proton Shuttle in a Molecular Rack‐and‐Pinion Cascade Achieving Macroscopic Crystal Deformation

Stereoselective Solid-State Synthesis of Biologically Active Cyclobutane and Dicyclobutane Isomers via Conformation Blocking and Transference

Conformations in the solid state are typically fixed during crystallization. Transference of "frozen" C=C conformations in 3,5-bis((E)-2-(pyridin-4-yl)vinyl)methylbenzene (CH3-3,5-bpeb) by photodimerization selectively yielded cyclobutane and dicyclobutane isomers, one of which (Isomer 2) exhibited excellent in vitro anti-cancer activity towards T-24, 7402, MGC803, HepG-2, and HeLa cells.

Temperature-Dependent Separation of CO2 from Light Hydrocarbons in a Porous Self-Assembly of Vertexes Sharing Octahedra

Design of flexible porous materials where the diffusion of guest molecules is regulated by the dynamics of contracted pore aperture is challenging. Here, a flexible porous self-assembly consisting of 1D channels with dynamic bottleneck gates is reported. The dynamic pendant naphthimidazolylmethyl moieties at the channel necks provide kinetic gate function, that enables unusual adsorption for light hydrocarbons. The adsorption for CO2 is mainly dominated by thermodynamics with the uptakes decreasing with increasing temperature, whereas the adsorptions for larger hydrocarbons are controlled by both thermodynamics and kinetics resulting in an uptake maximum at a temperature threshold. Such an unusual adsorption enables temperature-dependent separation of CO2 from the corresponding hydrocarbons.

Crystal structure of 4,4'-(diazenediyl)dipyridinium nitrate perchlorate

The title compound, C10H10N4 2+·NO3 -·ClO4 -, was obtained unexpectedly by the reaction of Co(ClO4)2·6H2O and cytidine-5'-monophosphate with 4,4'-azo-pyridine in an aqueous solution of nitric acid. The mol-ecular structure comprises two planar 4,4'-diazenediyldipyridinium dications lying on inversion centres and perchlorate and nitrate anions in general positions. In the crystal, N-H⋯O hydrogen bonds between dications and anions lead to the formation of [232] chains.

Multi-step Phase Transformation from Metal-Organic Frameworks to Inorganic Compounds for High-Purity Th(IV) Generation

The generation of high-purity thorium is the precondition for next-generation nuclear energy; however, this remains a challenging task. To this end, we present herein an ultrasimple technique with the combination of crystallization plus phase transformation. Crystallization into ECUT-68 is found to show almost 100% selective uptake of Th(IV) over rare earth and UO₂²⁺ ions, while multistep phase transformation from metal-organic frameworks (MOFs) to inorganic compounds is found to directly generate inorganic Th(IV) compound and then Th(IV) solution, suggesting its superior application in the generation of high-purity thorium.

Ultrafast Single-Crystal-to-Single-Crystal Transformation from Metal-Organic Framework to 2D Hydroxide

Single-crystal-to-single-crystal (SCSC) transformations have received considerable interest in crystal engineering, owing to providing a key platform for creating new materials. However, because of the limited tolerance of chemical bonds against the lattice strains, it is challenging to maintain the crystallinity when the structure changes dramatically. Here, a peculiar SCSC transformation from organic crystals to inorganic crystals, simultaneously achieving a drastic change in structure, connectivity, and dimension, is reported. As a demonstration, after reacting with liquid gallium, zeolitic imidazolate framework-8 (ZIF-8) can easily transform to 2D hydroxide single crystals. Interestingly, long-range ordered metallic atoms of hydroxide inherited from the ordered atomic arrangement of ZIF-8, but the connectivity is distinct. With good universality and extensibility, this transformation vastly expands the research scope of the SCSC transformations and provides a novel pathway for the synthesis of crystalline materials.

Solid-state behaviors of imines: colossal biaxial positive thermal expansion, motion capability, and phase transitions

The torsional flexibility of imines affects solid-state packing and properties. Behaviors including colossal thermal expansion, pedal motion, and phase transitions in imine-containing solids are described.

Dual-3D Femtosecond Laser Nanofabrication Enables Dynamic Actuation

Strategies that can make general materials smart are highly desired for developing artificial shape-morphing systems and devices. However, at present, it still lacks universal technologies that enable designable prototyping of deformable 3D micro-nanostructures. Inspired by natural automation systems, for instance, tendrils, leaves, and flowers deform dynamically under external stimuli by varying internal turgor, we report a dual-3D femtosecond laser processing strategy for fabricating smart and deformable 3D microactuators based on general photopolymers. By programming the size and distributions of voxels at the nanoscale, both the 3D profile and the 3D internetwork of a general photopolymer could be tailored in a controlled manner; thus, 3D microstructures encoded with precisely tailored networks could perform predictable deformations under certain stimuli. Using this dual-3D fabrication approach, energetic 3D microactuators, including a smart microflower, a responsive microvale, and an eight-finger microclaw, that permit controllable manipulation have been successfully developed.

Effects of dynamic pedal motion and static disorder on thermal expansion within halogen-bonded co-crystals

Thermal expansion is investigated for halogen-bonded co-crystals containing molecules that exhibit dynamic motion, lack motion ability, or experience static disorder.

Cooling-rate dependent single-crystal-to-single-crystal phase transition in an organic co-crystal

A reversible single-crystal-to-single-crystal phase transition is achieved via slow cooling; flash cooling locks the crystal in a kinetically trapped phase.

Irreversible solvent-assisted structural transformation in 3D metal-organic frameworks: Structural modification and enhanced iodine-adsorption properties

In this work, we demonstrate a solvent-assisted structural transformation between two 3D metal-organic frameworks (MOFs) ([Zn₄(α-bptc)₂(H₂O)₃]_n (1) → {[Zn₂(α-bptc)(H₂O)₄]·(pra)}_n (2)) (α-H₄bptc = 2,3,3',4'-biphenyl tetra-carboxylic acid and pra = pyridin-2-amine) at room temperature by immersing complex 1 in a mother solution. The structural transformation involves not only solvent exchange but also the cleavage and formation of coordination bonds, which is confirmed by infrared spectroscopy, single-crystal X-ray diffraction analysis, powder X-ray diffraction patterns, and thermogravimetric analysis. Structural analyses revealed that significant modifications occurred during the transformation including the changes in lattice parameters, unit cell volume, space group, coordination number, secondary building units, and topological type. In the case of drastic structural transitions, significant changes in properties were also observed. Complex 2 displayed the interesting uptake and release of iodine with the changes in visible color, UV and fluorescence spectra, and fully reversible I2 uptake of 8.5 mg g-1, which further suggested about its future application as iodine absorbing material.

Nanoarchitectonic-Based Material Platforms for Environmental and Bioprocessing Applications

The challenges of pollution, environmental science, and energy consumption have become global issues of broad societal importance. In order to address these challenges, novel functional systems and advanced materials are needed to achieve high efficiency, low emission, and environmentally friendly performance. A promising approach involves nanostructure-level controls of functional material design through a novel concept, nanoarchitectonics. In this account article, we summarize nanoarchitectonic approaches to create nanoscale platform structures that are potentially useful for environmentally green and bioprocessing applications. The introduced platforms are roughly classified into (i) membrane platforms and (ii) nanostructured platforms. The examples are discussed together with the relevant chemical processes, environmental sensing, bio-related interaction analyses, materials for environmental remediation, non-precious metal catalysts, and facile separation for biomedical uses.

Macroscopic crystalline deformation in an organic dye during reversible phase transition caused by alkyl disorder

Single crystals of a bisazomethine dye exhibit thermally induced reversible crystalline deformation due to alkyl disorder.