Synthesis of structurally enhanced magnetite cored poly(propyleneimine) dendrimer nanohybrid material and evaluation of its functionality in sustainable catalysis of condensation reactions

Nitrogen-Enriched Biguanidine-Functionalized Cobalt Ferrite Nanoparticles as a Heterogeneous Base Catalyst for Knoevenagel Condensation under Solvent-Free Conditions

Designing efficient, economical heterogeneous catalysts for the Knoevenagel condensation reaction is highly significant owing to the importance of reaction products in industries as well as pharmaceutics. Herein, we have designed and synthesized biguanidine-functionalized basic magnetically retrievable cobalt ferrite nanoparticles (CFNPs) for the synthesis of Knoevenagel condensation products using benzaldehydes and active methylene compounds (malononitrile/ethyl cyanoacetate/cyanoacetamide). Several advanced techniques, such as Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibration sample magnetometry (VSM), were utilized to precisely characterize the catalyst. The robust features of the current approach involve outstanding catalytic performance, solvent-free reaction conditions, ease of catalyst retrievability, easy workup procedure, large substrate tolerance, high turnover frequency (TOF) values (up to 486.88 h-1), values of green chemistry metrics such as E-factor (0.15), reaction mass efficiency (RME) value (87.07%), carbon efficiency (93.4%), and atom economy (AE) value (88.10%) close to their ideal values, and recyclability up to eight runs without a considerable reduction in activity, boosting the appeal of this approach from a commercial and ecological point of view.

Using a Modified Polyamidoamine Fluorescent Dendrimer for Capturing Environment Polluting Metal Ions Zn2+, Cd2+, and Hg2+: Synthesis and Characterizations

One of the most pressing global concerns is how to provide a clean environment for future generations given the exacerbation of urban, agricultural, industrial, and economic activities due to the escalating size of the global population. A polyamidoamine (PAMAM) dendrimer peripherally modified with 4-N,N′-dimethylethylenediamine-1,8-naphthalmide as a chromophore was synthesized and utilized to capture hazardous heavy metal ions. This modified fluorescent dendrimer (FCD) was complexed with Group 12 metal ions (Zn2+, Cd2+, and Hg2+) at a 2:1 (metal: FCD) ratio. Electronic absorption, fluorescence emission, Infra-red (IR), and nuclear magnetic resonance (1H NMR) spectroscopies, conductivity, CHN elemental, thermogravimetry, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses were used to characterize the resulting metal complexes. These assays revealed that the synthesized complexes were yellow-colored, thermally stable, nanoscale-sized, and composed of [M2FCD]·4Cl2. Considerable spectral shifts were observed in the emission and absorption spectra of the FCD molecule after binding the Zn2+ ions, which can be used to differentiate the Zn2+ complex from the other two complexes. This work provides basic data to facilitate the detection, quantification, and removal of environmentally hazardous heavy metal ions through complexation with a fluorescent dendrimer.

Synthesis of ultrafine AuPd bimetallic nanoparticles using a magnetite-cored poly(propyleneimine) dendrimer template and its sustainable catalysis of the Suzuki coupling reaction

A rational synthesis of magnetically recyclable PPI dendrimer encapsulated AuPd bimetallic nanoparticle and its catalytic examination in the Suzuki coupling reaction.