A novel method with great universality for preparing the electron-rich and electron-deficient triazine-heterocycle azacyanines was presented by using only dibromomethane as a catalysis and solution. The high boiling temperature of dibromomethane has a more flexible reaction condition, allowing all three azacyanine products a chance to yield over 80%. The FT-IR element analysis and all necessary tests, even signal-crystal tests, were executed to firmly confirm that the molecular structure of the azacyanines was accurate. This principal reaction route design that provides a new opportunity for the preparation of azacyanines and their derivatives in a cost-effective and simple process shows great potential for industrial-scale preparation of this important azacyanine intermediate product.Keywords:triazine-heterocyclic azacyanine preparation;reaction process optimization;dibromomethane based solution-free method
Jinshi Han,Yawei Zhou,Guanghang Bai,Wei Wei,Xiaoya Liu,Xiaojie Li
Thermoset polyurethanes have been applied in various fields by virtue of their outstanding properties. However, the thermosets cannot be recycled due to their permanent crosslinking structure, which exerts a detrimental influence on the environment. Recently, the upsurge in the field of covalent adaptable networks (CANs) has attracted tremendous attention. Despite many efforts being dedicated to the design of CANs, the creep resistance of CANs holds much room for further improvement at high temperature. Here, we designed a kind of azine chain extender and prepared a series of dynamic polyurethane networks in varying azine proportions. The azine-containing CANs possess high creep temperature of ∼100 °C attributed to the stability of the azine moieties. Besides, the azine-containing polyurethanes also exhibit outstanding mechanical properties and reprocessability due to the conjugated structure and exchangeability of the azine moieties. The azine-containing polyurethanes also present good antibacterial properties as the azines are a special category of Schiff base. This work demonstrated that azine moieties could enhance the creep resistance, which is a long-term and crucial issue for dynamic covalent polyurethanes and endows the dynamic covalent polyurethane networks with excellent mechanical properties and intrinsic antibacterial properties.
Hexanal, a volatile organic compound (VOC), is a potential biomarker for the early detection of lung cancer. In this study, we developed a dual-mode flexible biosensor that integrates surface-enhanced Raman scattering (SERS) and colorimetric detection for the quantitative analysis of hexanal in human exhaled breath. The biosensor employs Ag nanocubes wrapped with Co-Ni layered double hydroxide (AgNCs@Co-Ni LDH) as a functional matrix, offering both superior SERS enhancement and efficient VOC adsorption properties. To achieve selective detection, AgNCs@Co-Ni LDH was incorporated into agarose hydrogels along with 3-methyl-2-benzothiazolinone hydrazone (MBTH). The resulting MBTH-AgNCs@Co-Ni LDH/hydrogel patches facilitate the oxidation of hexanal, enabling simultaneous colorimetric and SERS signal generation, while producing acrizine, a blue-colored reaction product. This hydrogel-based dual-mode sensing platform exhibits high selectivity, excellent stability, and precision in SERS-based hexanal detection. The detection limit for the SERS method was determined to be as low as 3.34 × 10 −13 M. Furthermore, developed and optimized compact CNN-based multi-terminal intelligent recognition system for enhanced hydrogel-patch detection through AI-driven, portable, and real-time colorimetric analysis. Therefore, this work not only enables the effective detection of hexanal in the exhaled breath of suspected lung cancer patients, underscoring its potential for early lung cancer screening, but also establishes a foundation for the development of multimodal hydrogel biosensors for broader applications in disease diagnosis.
危险品化学品经营许可证（带存储）