Plastic Recovery and Utilization: From Ocean Pollution to Green Economy

Due to their numerous merits (such as high durability, diverse applicability, ready-availability, low-cost, reusability, and so on), the presumably inevitable use of plastics makes their waste ubiquitously dispersed in our environment, especially in the oceans. The environmental damage posed, especially to the ecosystem, initiated the need for recourse control of these environmentally refractory pollutants. In this review, the various sources, classifications, fate, and control measures of plastic wastes were appraised. Further, of the three primary techniques for resource control, pyrolysis was reviewed in-depth, showing its relevance and superiority over others. Specific case studies showed that liquid and gaseous fuels derived from pyrolyzed plastics are a waste-to-wealth system that requires optimization and intensification. Such an approach would further help rid our planet of the numerous plastic wastes while improving our economy and achieving our energy demand. One approach identified to improve the current pyrolysis technology is catalysis. Further research should devise green methods for organic catalysis, which are environmentally benign.

A Compendium of the Most Promising Synthesized Organic Compounds against Several Fusarium oxysporum Species: Synthesis, Antifungal Activity, and Perspectives

Vascular wilt caused by F. oxysporum (FOX) is one of the main limitations of producing several agricultural products worldwide, causing economic losses between 40% and 100%. Various methods have been developed to control this phytopathogen, such as the cultural, biological, and chemical controls, the latter being the most widely used in the agricultural sector. The treatment of this fungus through systemic fungicides, although practical, brings problems because the agrochemical agents used have shown mutagenic effects on the fungus, increasing the pathogen’s resistance. The design and the synthesis of novel synthetic antifungal agents used against FOX have been broadly studied in recent years. This review article presents a compendium of the synthetic methodologies during the last ten years as promissory, which can be used to afford novel and potential agrochemical agents. The revision is addressed from the structural core of the most active synthetic compounds against FOX. The synthetic methodologies implemented strategies based on cyclo condensation reactions, radical cyclization, electrocyclic closures, and carbon–carbon couplings by metal–organic catalysis. This revision contributes significantly to the organic chemistry, supplying novel alternatives for the use of more effective agrochemical agents against F. oxysporum.

The Ionic Organic Cage: An Effective and Recyclable Testbed for Catalytic CO2 Transformation

Porous organic cages (POC) are a class of relatively new molecular porous materials, whose concept was raised in 2009 by Cooper’s group and has rarely been directly used in the area of organic catalysis. In this contribution, a novel ionic quasi-porous organic cage (denoted as Iq-POC), a quaternary phosphonium salt, was easily synthesized through dynamic covalent chemistry and a subsequent nucleophilic addition reaction. Iq-POC was applied as an effective nucleophilic catalyst for the cycloaddition reaction of CO2 and epoxides. Owing to the combined effect of the relatively large molecular weight (compared with PPh3+I−) and the strong polarity of Iq-POC, the molecular catalyst Iq-POC displayed favorable heterogeneous nature (i.e., insolubility) in this catalytic system. Therefore, the Iq-POC catalyst could be easily separated and recycled by simple centrifugation method, and the catalyst could be reused five times without obvious loss of activity. The molecular weight augmentation route in this study (from PPh3+I− to Iq-POC) provided us a “cage strategy” of designing separable and recyclable molecular catalysts.

Umpolung of Donor-Acceptor Cyclopropanes via N-Heterocyclic Carbene Organic Catalysis

A carbene-catalyzed formal umpolung of Donor-Acceptor (D-A) cyclopropanes is disclosed. The cyclopropane moiety is connected to an acetyl aldehyde that can be activated by a carbene catalyst. The initially electrophilic...

Insights into the Extraction of Photogenerated Holes from CdSe/CdS Nanorods for Oxidative Organic Catalysis

Using aerobic oxidative coupling of thiolphenol in organic media as a model reaction, we show that photogenerated holes in CdSe/CdS core-shell nanorods can be efficiently exctracted. As a result, CdSe/CdS...

Enantioselective Modification of Sulfonamides and Sulfonamide-Containing Drugs via Carbene Organic Catalysis

A carbene-catalyzed method for highly enantioselective modification of sulfonamides is disclosed. The reaction proceeds under mild conditions with broad substrate scope, wide functional group tolerance, and good to excellent yields....

Recent Developments on Noble Metal Based Microparticles for Their Applications in Organic Catalysis

Noble metal microparticles have been employed as desired catalysts for a number of classical organic chemical reactions due to their unique physicochemical properties. Currently, in order to obtain more benefits for practical applications such as low cost, easy separation and high selectivity, many efforts of scientists are devoted to constructing composite microparticles in which noble metals are coupled with other materials. In this paper, we summarize some recent research developments on noble metal based microparticles for their catalytic applications in organic synthesis. Among them, application of the gold and silver based microparticles is the focus of this paper for their relatively low cost and the diversity of preparation methods. Furthermore, the challenges and prospects of noble metal based microparticles for their applications in organic catalysis are also discussed.

The chemistry of biguanides: from synthetic routes to applications in organic chemistry

In this minireview, we discuss the chemistry of biguanides and their applications in catalysis. We present their super basicity as a consequence of their structure, the most efficient ways to synthesize symmetric and unsymmetric functionalized biguanides, and their applications in organic catalysis as triazine precursors and ligands in organometallic catalysis.

Essentials for combined experimental and computational 77Se NMR of organoselenium catalysts and bioinspired antioxidants

: The importance of selenium in biology, in organic catalysis and green chemistry is well established. Selenoproteins, among which the ubiquitous glutathione peroxidases (GPx), play a key-role in mitigating the oxidative stress by reducing H2O2 and hydroperoxides using glutathione as cofactor. Organoselenides, particularly diphenyl diselenide, in presence of H2O2 are efficient and often green oxygen transfer agents in important organic reactions, such as Baeyer–Villiger oxidations of ketones/aldehydes, the conversion of alkenes into epoxides, and the oxidations of alcohols and nitrogen-containing compounds. NMR spectroscopy can facilitate the investigation of the properties of this element in a biological environment and the characterization of the peculiar species of its chemistry. In this short review, a brief overview of the experimental and computational 77Se NMR-based techniques is outlined, with a particular focus on their application to the study of biologically relevant organoselenium compounds and bio-mimetic systems. Experimental protocols together with computational methods used in different contexts are presented and their potential as efficient investigation tools is critically discussed. It emerges that while the 77Se NMR measurement is a consolidated technique, no standard computational protocol is available to compute the shielding constant of the chalcogen nucleus with accuracy and the optimal approach combines molecular dynamics in solution and quantum chemistry calculations to take into account the conformational freedom.