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Self-assembly exploits noncovalent interactions to offer a facile and effective method for the construction of soft materials with multifunctionalities and diversity. In this work, fluorescence carbon quantum dots coordinated by Ce3+ ions (CQDCe) have been synthesized and exploited as building blocks to generate a series of hierarchical structures through the ionic self-assembly of CQDCe and biomolecules, namely DNA, myoglobin (Mb), and hyaluronic acid (HA). In particular, vesicles can be constructed by the simple mixing of oppositely charged CQDCe and DNA in water. The formation of unusual vesicles can be explained by the self-assembly of CQDCe with a rearranged structure and the rigid DNA biomolecular scaffolds. This facile noncovalent self-assembly method has inspired the innovative use of virgin DNA as a building block to construct vesicles rather than resorting to a sophisticated synthesis. The self-assembly of CQDCe-biopolymers was accompanied by aggregation-induced photoluminescence (PL) quenching. The biosensing platform was designed to detect polypeptides and deoxyribonuclease I through competitive binding of CQDCe and enzymatic hydrolysis of the DNA backbone, respectively. We believe that the integrative self-assembly of CQDCe and DNA will enrich the theoretical study of vesicle formation by DNA molecules and extend the application of fluorescence carbon quantum dots in the biological field. [ABSTRACT FROM AUTHOR]

Copper nanoclusters (CuNCs) as a new class of fluorescent materials have attracted a great deal of interest due to their outstanding fluorescence properties. In this work, a variety of organic solvents were used to induce self‐assembly of glutathione‐capped CuNCs (GSH‐CuNCs) to form ordered assemblies with enhanced fluorescence properties. Assemblies with multicolor fluorescence emission were constructed on the basis of the aggregation‐induced emission (AIE) of GSH‐CuNCs and the solvent effect. The fluorescence emission from these GSH‐CuNCs assemblies can also be tuned from yellow to purple by changing the organic solvent. A possible mechanism based on the size of the assemblies and electron transfer was explored to explain the solvent effects on GSH‐CuNCs. Stimuli‐responsive nanoswitches with excellent reversibility can be controlled by changing the type of organic solvent and the ratio of the organic solvent to the aqueous solution of GSH‐CuNCs. As the CuNCs assemblies exhibit strong, stable, and color‐tunable fluorescence, they were employed as color‐conversion materials for recognizing different organic solvents. [ABSTRACT FROM AUTHOR]

A novel pyrrolopyrrole azadipyrrin (Janus‐PPAD) with Janus duality was synthesized by a Schiff base–forming reaction of diketopyrrolopyrrole. The orthogonal interactions of the hydrogen‐bonding ketopyrrole and metal‐coordinating azadipyrrin moieties in Janus‐PPAD enabled the metal ions to be arranged at regular intervals: zinc(II) and cobalt(II) coordination provided metal‐coordinated Janus‐PPAD dimers, which can subsequently form hydrogen‐bonded one‐dimensional arrays both in solution and in the solid state. The supramolecular assembly of the zinc(II) complex in solution was investigated by 1H NMR spectroscopy based on the isodesmic model, in which a binding constant for the elongation of assemblies is constant. Owing to the tetrahedral coordination, in the solid state, the cobalt(II) complex exhibited a slow magnetic relaxation due to the negative D value of −27.1 cm−1 with an effective relaxation energy barrier Ueff of 38.0 cm−1. The effect of magnetic dilution on the relaxation behavior is discussed. The relaxation mechanism at low temperature was analyzed by considering spin lattice interactions and quantum tunneling effects. The easy‐axis magnetic anisotropy was confirmed, and the relevant wave functions were obtained by ab initio CASSCF calculations. [ABSTRACT FROM AUTHOR]

Multicolor fluorescence emission assemblies with excellent reversibility were constructed based on aggregation-induced emission and the solvent effect of GSH-CuNCs. Stimuli-responsive nanoswitches with excellent reversibility can be controlled by changing the types of organic solvents and the ratio of organic solvent to GSH-CuNCs aqueous solution. As the CuNCs assemblies exhibit strong, stable, and color-tunable fluorescence, they are employed as the color conversion materials for recognizing different organic solvents. [Extracted from the article]