Urea-functionalized 4-ethynylbenzenes undergo facile formal [2 + 2] cycloaddition followed by retroelectrocyclization upon reaction with tetracyanoethylene, yielding 1,1,4,4-tetracyanobuta-1,3-dienes-based push–pull chromophores. Unlike the N,N′-dialkylamino group, urea functionalization provides easy access to further functionalization on these chromophores. The resulting chromophores exhibit unexpected white light emissions apart from various inherent properties like intramolecular charge-transfer band and redox behavior.

Herein, we report the efficacy of Brønsted acid‐functionalized CDs in an enriched preparation of 5‐hydroxymethylfurfural (HMF) and ethyl levulinate (EL) energy fuel building‐block compounds. The cheap p‐toluenesulphonic acid was used as a precursor to prepare CD‐SO3H by employing a simple, one‐pot and scalable protocol. The high‐end analytical techniques endorsed the catalyst's higher acid density and minimum particle size characteristics. Its glucose reaction evaluation resulted in an 82 mol% HMF using glucose via dehydration. Similarly, it enabled an 85 mol% EL from levulinic acid via esterification under modest reaction conditions. It also promoted the synthesis of other varieties of alkyl levulinates (such as levulinic acid 1‐butyl and methyl esters) with a similar yield result. The recyclability study showed that it could be reused for up to 5 cycles. Overall, the catalytic setup represented an environmentally‐friendly and feasible method for process development.

Tuneable selectivity in cross-Glaser products is achieved by tweaking the catalyst-backbone. The interaction responsible for this is unravelled.

Carbon dot (CD) and palladium nanoparticle (Pd NP) composites are semiconducting materials having tremendous applications in catalysis with suitable band gaps. However, their combination with a suitable polymer matrix in sonophotocatalysis has not been explored. Herein, we have synthesized and characterized a new nanohybrid catalyst from a polyamide cross-linked CD-polymer and subsequent deposition of Pd NPs. A sonocatalytic activity of 99% rhodamine B dye degradation was achieved in mere 5 min in the dark. A model catalyst replacing CDs with benzene and other control studies revealed that the synergistic effects of CDs and Pd NPs enhance the sonocatalytic activity of the nanohybrid catalyst. Interestingly, visible light did not influence the activity significantly. Mechanistic investigations suggest that generation of reactive oxygen species on the surface of the CD–polymer initiated by ultrasound, which is further facilitated by Pd NPs, is the key for remarkable catalytic activity (a rate constant of 0.99 min –1 ). Recyclable heterogeneous catalysts under ambient conditions are promising for exploring sono-assisted dark catalysis for several avenues.

In the past few decades, click chemistry (CuAAC reaction) has seen tremendous development both in terms of catalyst designing and method development because 1,2,3triazoles products have shown enormous applications in various fields. The sought after azide-alkyne cycloaddition reaction catalyzed by smaller-sized (~7 nm) Cu(I/II) oxide nanoparticles (Cu I/II O NPs) supported by thiol-functionalized cellulose provided triazole products in excellent yields (90-98%) with remarkable 1,4-regioselectivity, including the 10 g scale synthesis of a rufinamide drug intermediate. The possible reasons for this exceptional activity are the higher ratio of Cu (I), along with the smaller-sized and homogeneously dispersed colloidal nature of Cu I/II O NPs. Most importantly, the reaction underwent industrially friendly greener conditions such as aqueous medium, room temperature, and no additives, etc., suggesting promising for practical applications. The as-prepared catalyst was recycled and reused up to 5 cycles by simply filtering the precipitate 1,2,3-triazoles products without losing significant activity.