Smart windows have been paid much attention in recent years since they can save more energy in comparison with ordinary counterparts. However, exterior heating or electric system is still required to stimulate the color/transparency responses for current smart windows, which increases the complexity of device's structure and still consumes energy. Thus, sunlight‐responsive smart windows in building are particularly appealing for saving energy but seldom reported. Herein, we propose a facile and low‐cost method to construct reversible color/transparency switching materials by integrating the unique photothermal conversion feature of noble metal nanoparticles with thermochromic compounds. The switching behavior of thermochromic materials is not triggered by traditional exterior heating but laser/sunlight irradiation. In particular, we achieve ambient sunlight‐driven photo‐thermochromic smart windows (PTCSWs) prototype which can automatically become opaque to block sunlight on scorching days and return to a transparent state under low lighting condition. We believe that this work will pave a way for a novel class of smart windows which is highly expected to be integrated into building components to tailor specific camouflage coating and substantially save energy.
Structurally simple benzyl-type photolabile protecting groups (PPGs) have been developed to release alcohols and carboxylic acids. Release of two substrates from one PPG chromophore has also been accomplished.
The application of selenol‐X chemistry in nucleophilic substitution and Se‐Michael addition reactions for polymer chain end modification is presented. Selenol‐labeled polystyrene can easily react with alkyl halides, methyl methacrylate, methyl acrylate, pentafluorostyrene, etc. The mild conditions make it attractive for the synthesis of macromonomers. The resulting polymers are analyzed and characterized by UV, size‐exclusion chromatography (SEC), NMR, and matrix assisted laser desorption/ionization time of flight mass spectroscopy.
This paper describes the self-assembly of a new class of three-component dynamic [2]catenanes, which are driven or stabilized by intramolecular hydrogen bonding, coordination, and electrostatic interaction. One of the component molecules 2, consisting of an aromatic oligoamide spacer and two peripheral zinc porphyrin units, was designed to adopt a folded preorganized conformation, which is stabilized by consecutive intramolecular three-centered hydrogen bonds. Component molecule 3 is a linear secondary ammonium bearing two peripheral pyridine units, which was designed to form a 1:1 complex with 24-crown-8 (5). The 1H NMR and UV-vis experiments in CDCl3-CD3CN (4:1 v/v) revealed that, due to the preorganized U-shaped feature, 2 could efficiently bind 3 through the cooperative zinc-pyridine coordination to generate highly stable 1:1 complex 2.3. Adding 5 to the 1:1 solution of 2 and 3 led to the formation of dynamic three-component [2]catenane 2.3.5 as a result of the threading of 3 through 5. 1H NMR studies indicated that in the 1:1:1 solution (3 mM) [2]catenane 2.3.5 was generated in 55% yield at 25 degrees C. The yield was increased with the reduction of the temperature and [2]catenane could be produced quantitatively in a 1:1:2 solution ([2]=3 mM) at -13 degrees C. Replacing 3 with 1,2-bis(4,4'-bipyridinium)ethane (4) in the three-component solution could also give rise to similar dynamic [2]catenane 2.4.5 albeit in slightly lower yield.
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