Supramolecular Polymeric Fluorescent Nanoparticles Based on Quadruple Hydrogen Bonds

Abstract

5483wileyonlinelibrary.com biocompatibility. Accordingly, there has been a surge in the exploitation of CPNs in numerous exciting studies. [ 9 ] Covalent polymers, however, suffer from the need for tedious chemical modifi cation to tune the emission color of their corresponding nanoparticles.Supramolecular polymers, which are formed from low-molecular-weight monomers by noncovalent interactions, provide a promising scaffold for the fabrication of fl uorescent nanoparticles with well fi ne-tuned emission properties. [ 10 ] On the one hand, the small building blocks of supramolecular polymers provide synthetic accessibility superior to that of covalent polymers. On the other hand, the excitation energy transfer from energy donor to acceptor fl uorophores of the monomers occurs effi ciently in supramolecular copolymers. Such a process can be used to adjust the emission properties of functional materials. [ 11 ] Recently, we have reported the synthesis of water-dispersible nanospheres of hydrogen-bonded supramolecular polymers by the miniemulsion method. [ 12 ] Bis-ureidopyrimidinone (Bis-UPy) monomers polymerized through the quadruple H-bonding of the ureidopyrimidinone (UPy) motif to form supramolecular polymers, [ 13 ] which further aggregated into nanospheres in the emulsifi ed organic droplets. Herein, we prepared FNPs based on fl uorophore-functionalized Bis-UPys by the miniemulsion method ( Scheme 1 ). The emission properties of the nanoparticles could be fi ne-tuned by effi cient excitation energy transfer in co-assemblies of the energy donor and acceptor fl uorophore-based monomers. The photoswitchable FNPs with high on-off fl uorescence contrast (85%) were prepared by copolymerization of Bis-UPys containing fl uorophore and photochromic dithienylethene. The FNPs have been successfully applied in cellular imaging and as fl uorescent inks. Results and Discussion Synthesis, Preparation, and Characterization of FNPsFour fl uorophore-functionalized Bis-UPys were synthesized for the preparation of supramolecular polymer-based fl uorescent nanoparticles: Based on their different emission colors, fl uorophore 9,10-diphenylanthracene, 1,3,5,7-tetramethyl boron dipyrromethene (BODIPY), 3,5-dithiolated BODIPY, and naphthalene bisimide were chosen as the functional groups A facile approach for the preparation of supramolecular polymer-based fl uorescent nanoparticles (FNPs) is reported. FNPs with homogeneous shape and size distribution are fabricated from low-molecular-weight molecules, and thus, different compositional constituents can be effi ciently incorporated via copolymerization. The emission color of the FNPs covers a wide region from blue to near infrared and can be easily tuned using effi cient excitation energy transfer. The photoswitchable fl uorescent nanoparticles with high on-off fl uorescence contrast are also simply prepared by copolymerization of monomers containing a fl uorophore and a photochromic unit. Our FNPs are successfully applied in living cell imaging and as fl uorescent inks.

Organic Composite Crystal with Persistent Room-Temperature Luminescence Above 650 nm by Combining Triplet–Triplet Energy Transfer with Thermally Activated Delayed Fluorescence

“…Likewise, composite crystals of D and a non-TADF analog of A, A′ with a similar absorption spectrum as A manifested no detectable luminescence (Supporting Information Figure S11). This result is consistent with nonradiative relaxation of T 1 of A′ populated by an efficient triplet-to-triplet energy transfer from D. Although tuning emission properties by excitation energy transfer has been investigated extensively, 34,35,[39][40][41][42][43][44][45] to the best of our knowledge, our material is the first example to manifest persistent TADF by using triplet-triplet energy transfer.…”

Photoswitchable Fluorescent Liquid Crystal Nanoparticles and Their Inkjet‐Printed Patterns for Information Encrypting and Anti‐Counterfeiting

“…Here, the water‐dispersible nature makes the aqueous dispersion of the photoswitchable fluorescent LCNPs as green and eco‐friendly inks that are first applied to information encryption technology. Considering accuracy, readability of information, and operation simplicity of the information writing, inkjet printing is particularly appropriate when LCNPs are employed to construct system . The aqueous suspension in which the polymerized LCNPs are dispersed was concentrated by evaporating water at room temperature.…”

Programmable two-dimensional nanocrystals assembled from POSS-containing peptoids as efficient artificial light-harvesting systems

“…S34). It further demonstrated that these POSS-containing 2D nanocrystals functioned as excellent light-harvesting systems ( 28 , 58 ).…”