Carbazole based nanoprobe for selective recognition of Fe3+ ion in aqueous medium: Spectroscopic insight

A Deferasirox Derivative That Acts as a Multifaceted Platform for the Detection and Quantification of Fe3+

Here, we report that ExSO3H, a synthetically accessible, water-soluble, non-toxic derivative of the clinical iron chelator deferasirox, acts as a colorimetric chemosensor that permits the detection and quantification of Fe3+ in aqueous samples at pH 2–5. In addition, we observed that a fluorescent turn-on response was produced when this chelator was allowed to interact with human serum albumin (HSA). This fluorescence was quenched in the presence of Fe3+, thus allowing us to monitor the presence of this biologically important metal cation via two independent methods.

Machine-Learning-Driven Synthesis of Carbon Dots with Enhanced Quantum Yields

Knowing the correlation of reaction parameters in the preparation process of carbon dots (CDs) is essential for optimizing the synthesis strategy, exploring exotic properties, and exploiting potential applications. However, the integrated screening experimental data on the synthesis of CDs are huge and noisy. Machine learning (ML) has recently been successfully used for the screening of high-performance materials. Here, we demonstrate how ML-based techniques can offer insight into the successful prediction, optimization, and acceleration of CDs' synthesis process. A regression ML model on hydrothermal-synthesized CDs is established capable of revealing the relationship between various synthesis parameters and experimental outcomes as well as enhancing the process-related properties such as the fluorescent quantum yield (QY). CDs exhibiting a strong green emission with QY up to 39.3% are obtained through the combined ML guidance and experimental verification. The mass of precursors and the volume of alkaline catalysts are identified as the most important features in the synthesis of high-QY CDs by the trained ML model. The CDs are applied as an ultrasensitive fluorescence probe for monitoring the Fe³⁺ ion because of their superior optical behaviors. The probe exhibits the linear response to the Fe³⁺ ion with a wide concentration range (0-150 μM), and its detection limit is 0.039 μM. Our findings demonstrate the great capability of ML to guide the synthesis of high-quality CDs, accelerating the development of intelligent material.

The impact of phenyl–phenyl linkage on the thermodynamic, optical and morphological behavior of carbazol derivatives

The impact of structural differentiation between phenylcarbazoles (PhC, mCP, CBP, TCB) and phenylamines (TPA, BDB, TPB, TDAB) on the phase equilibria, optical spectrum, band gap, and thin-film morphology is evaluated and discussed. The carbazolyl units lead to a lower electronic conjugation contributing to a wide band gap when compared with the diphenylamine analogs. The fusion and sublimation equilibria indicate that entropic contribution is the key factor for the distinguished melting behavior and solid-phase volatility between phenylcarbazole derivatives and phenylamine analogs. The molecular differentiation between the two classes of compounds is not reflected in the crystal packing and intermolecular interactions. However, compared with the diphenylamino groups, the incorporation of carbazolyl moieties contributes to a less flexible molecule. Moreover, the results evidence that intermolecular bonding disruption along the fusion transition is more extensive for phenylamine derivatives. Due to the asymmetric nonplanar structure, mCP is characterized by a ratio of {T_g/T_m ≈ 3/4} while the more symmetric CBP and TCB molecules display ratios closer to {T_g/T_m ≈ 2/3}. Vapor-deposited thin films of mCP, CBP, and TCB are amorphous and their morphology is highly dependent on the substrate roughness. The lower flexibility of nonplanar phenylcarbazoles induces the formation of a glassy state due to the harder packing mechanism leading to the lower ability of the crystallization process.

The phenyl–phenyl linkage in N-phenylcarbazoles contributes to several optical, structural, thermodynamic and morphological changes.

Ultrasensitive and highly selective detection of Cu2+ ions based on a new carbazole-Schiff

A new chemosensor for Cu²⁺ based on Schiff base with high sensitivity and selectivity was designed and synthesized. The fluorescence intensity of the chemosensor in CH₃CN solution was enhanced 160-fold after the addition of 10 equiv. Cu²⁺ over other metal ions. In addition, it also facilitates colorimetric detection for Cu²⁺ in CH₃CN solution. The chemosensor displayed low detection limit and fast response time to Cu²⁺.