Chemical Review and Letters
Volume:6 Issue: 3, Summer 2023

Compared with most studies in the field of CO2 utilization, which focused on the carboxylation of C-I, C−Br, C−Cl, C−B, C-Si, C-O bonds, the direct defluorinative carboxylation of C−F bonds is more challenging due to the much higher bond dissociation energy and less reactivity of C−F bonds, for which it is difficult to initiate the oxidative addition process under mild conditions. Recently, various catalytic systems have been developed that allow the direct carboxylation of inert C-F bonds with atmospheric CO2 and provide versatile methodologies for green synthesis of carboxylic acid derivatives. This review focuses on recent advances in this challenging and hot research topic with special emphasis on the mechanistic details of the reaction pathways.

This paper reports a detailed review of the chemistry and associated mechanisms of cellulose modification by chemical methods. Several chemical modification reactions are carried out on the surface of nanocellulose material to enhance their adsorption capacities for specific contaminants and take advantage of their biodegradability. Chemical modification of nanocellulose is an effective method of producing nanocellulose adsorbents with low hornification, improved dispersion in water, reduced swelling, and improved affinity for heavy metal ions. Standard modification processes reviewed include acetylation, esterification, and oxidation of the surface hydroxyl group. Modified nanocellulose materials are effective adsorbents of heavy metal ions and organic dyes with over 80 mg/g adsorption capacities.

The technique for the separation of itaconic acid from fermented broth has a substantial impact on overall manufacturing costs. To make biorefineries sustainable and profitable, optimization and highly efficient downstream processes are technological hurdles. Itaconic acid has previously been separated using processes like crystallization, extraction, electrodialysis, diafiltration, precipitation, adsorption, and pertraction. Crystallization is a common way to separate itaconic acid from fermented broth, but other methods, viz., reactive extraction and membrane separation, show promise as recovery processes that could be used with fermentation to increase the yield of the process. In this study, the distribution coefficients were obtained from 1.89-4.05 with extraction efficiencies of 65.35-80.20% at 10–50 vol% of tri-n-butyl phosphate with iso-octanol. The maximum separation of itaconic acid was observed with 50% tri-n-butyl phosphate at 0.051 mol.L-1 of itaconic acid. The loading ratio was less than 0.5, showing that the complex was formed 1:1 (acid: extractant) in the organic phase. The results indicate that iso-octanol with tri-n-butyl phosphate could be further used as a solvent to the separation of itaconic acid.

In the present study, the density functional theory (DFT) method has been used to investigate the interplay effects between cation–π and intramolecular hydrogen bond (IMHB) interactions in the complexes formed by the mesalazine and metal cations (Li+, Na+, K+, Be2+, Mg2+ and Ca2+). The topological properties and the charge transfer values are estimated using the atoms in molecules (AIM) and natural bond orbital (NBO) analyses, respectively. The results indicate that the coupling simultaneously decreases the IMHB strength and increases the cation–π interaction. Our data also show that the strength of cation–π interactions enhances with increasing the charge-to-radius ratio of the cations, while the reverse results are observed for the IMHB interactions. Finally, the frontier molecular orbitals are applied to evaluate the conceptual DFT parameters such as energy gap, chemical hardness and electronic chemical potential of the complexes.

The remarkable ability of pyrazolo[1,2-b]phthalazines as a nitrogen-containing heterocycles with fused scaffold of bridgehead hydrazine and pyrazole moieties have generated substantial interest in the pharmaceutical industry and in the diversified field of synthetic chemistry. The present mini-review focuses on current progress in the synthesis of 1H-pyrazolo[1,2‑b]phthalazine-5,10-dione derivatives using multi-component reaction of phthalhydrazide, aldehyde and malononitrile and covers publications from 2015 up to now.

In this DFT approach, we are performed geometrically and electronically properties of Ti—N nanoheterocages developed from C20 fullerene with the molecular formula of C20-2nTinNn (n = 1-8), at B3LYP/6-311++G**, M062X/6-311++G**, B3PW91/6-311++G**, and B3LYP/AUG-cc-pVTZ levels of theory. Based on the vibrational frequency analysis, except for C4Ti8N8 structure, others are real minima and none deform as segregated open cage. Substituted doping C20 to its C20-2nTinNn derivatives are caused different ΔEHOMO-LUMO values and conductivity, so that there is no uniformity between the ΔEHOMO-LUMO and n (number of substituting Ti―N units) and C18Ti1N1 is found as the best insulated nanoheterofullerene, while C12Ti4N4 is considered as the strongest conductive nanocage. The results show good reliability among polarizability, and ionization potential with n. Thermodynamic stability and aromaticity (NICS values at cages centers) decreases as n increases. As such, the strong ring current in C18Ti1N1 becomes weak in other nanostructures studied under work because the pπ electrons are slightly shifted from Ti to N (and C) atoms also portions of valence electrons keep on localized over the N (and C) nuclei. Accordingly, on account of lack of N—N bonds and dispersion of eight Ti—N bonds in the symmetrical positions of cage, the C4Ti8N8 species conserves the cage structure, showing the lowest dipole moment of 0.00 Debye and the lowest positive charge on Ti atoms (+0.526). Considering the least absolute value of hydrogen adsorption energy │−18.9 kcal/mol│ and the highest positive charge on titanium heteroatom of C18Ti1N1 (+1.269), it seems that C18Ti1N1 is the best candidate for hydrogen storage.

In this study, the effect of substitution (CH2OCH3, Cl, F, NHCH3, NO2, OH, Ph, PhOCH3, and SH) on the hydrogen bonding energies of N-H···S intramolecular bridges in the 3-amino-propene thial and its analogous compound, 2-hydrazineylidene-ethane thial, is examined using density functional theory (DFT). The outcomes reveal that the compounds containing the Ph and F substitutions possess the strongest and weakest hydrogen bonds. In other words, the electron-donating substitutions strengthen the hydrogen bond, whereas electron-withdrawing ones weaken it. The hydrogen bonding formation can cause elongation of the N-H bond and shortening of the H∙∙∙S distance. The findings derived from atoms in molecules (AIM) calculations show characteristics of closed-shell interactions and also the electrostatic nature of the H∙∙∙S bonding. Moreover, the natural bond orbital (NBO) approach is employed to compute the interaction between the LPS and the σ∗N−H, which reveals that the largest interaction is related to the strongest hydrogen bond. Finally, to investigate the effect of the environment on the strength of hydrogen bonding, the calculations are conducted in two solvents, namely water and CCl4. The outcomes indicate that hydrogen bonding strength is lower in the solution as compared to the gas phase.

In December 2019, an infectious respiratory disease caused by a new severe acute respiratory syndrome-related coronavirus (SARS-CoV-2), was reported in the city of Wuhan in China. Due to its fast expansion, the so-called “COVID-19” disease rapidly turned into a global pandemic and brought unprecedented challenges for the global community. Since its declaration by the world health organization (WHO) in February 2020, all healthcare professionals throughout the world have been trying to mitigate the spread of this virus and manage this disaster. Amongst various ongoing efforts, early detection of this virus and diagnosis of individuals and groups whom are infected with SARS-CoV-2 are pivotal steps that should be accomplished in the earliest possible moment. Nanostructures which are often used for targeting specific biological markers, can be considered as potential candidates for rapid detection of SARS-CoV-2, especially when fast, portable, easy-to-use, and accurate in-field detection kits are required. In this Review, we have summarized recent advances in the detection of coronaviruses in which nanostructures have been utilized to either generate or amplify the detection signal. Potential benefits of implementing nanostructures in the detection of SARS-CoV-2 has also been demonstrated. The applicability of coupling current detection methods with smartphone-based platforms, array-based sensing systems, wearable gadgets and other future directions of SARS-CoV-2 detection techniques have been further discussed.

The adsorption of an anionic dye (ARS) on raw typha grass (RAW-TG) was studied using an equilibrium batch approach. To test their impact on the ARS removal, the operational parameters of contact time (15 minutes), starting dye concentration (120 mg/L), adsorbent dosage (0.02 g), and pH (8) were tuned. Among the physical properties that were looked at were the RAW-TG's bulk density (0.397 g/cm3), pore volume (1.253 cm3), and moisture content (17.80 %). To better characterize the adsorbent, it was further studied using scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), and point of zero charges (PZC) techniques. To numerically model equilibrium data, the Langmuir, Freundlich, Temkin, and Dubining Radushkevich (D-R) models were utilized. Pseudo-first-order, pseudo-second-order, Elovich, and Intraparticle diffusion models were used to calculate the adsorption kinetics. Using the Van't Hoff plot, the thermodynamic parameters affecting the adsorption process were calculated. The data were presented most effectively by a pseudo-second-order model with a maximum adsorption capacity of 46.511 mg/g, and Freundlich's interpretation of the adsorption isotherm was significantly more favorable than that of the other models examined. According to the thermodynamic characteristics, the process was viable and spontaneous, with adsorption values of ΔG (-6.737 to -8.271 kJ/mol), ΔH (16.616 kJ/mol), and ΔS (16.616 J/molK, respectively. The findings of this investigation demonstrate that RAW-TG is an efficient, reasonably priced, and environmentally friendly adsorbent for the removal of ARS dye from aqueous solutions.

The worthwhile contributions made to the literature by researchers on the ligation behaviour of Schiff bases derived from anthranilic acid and their applications is hitherto not togetherized. This review covers a comprehensive bibliographic perusal of anthranilic acid-derived Schiff bases and their chelates reported circa over the last three decades (1990 - 2022) with a view to furnishing information that will help researchers in the design of new Schiff bases as potential candidates in different applications. A scrupulous survey of the literature suggests that anthranilic acid-derived Schiff bases preferentially ligate metal ions through azomethine nitrogen (-N=CH-) and the hydroxyl oxygen (OH) of the carboxyl group after deprotonation rather than chelating via the carbonyl oxygen (C=O). However, a pocket of the literature reported the coordination sites as the iminic nitrogen (-N=CH-) and carbonyl oxygen (C=O) of the carboxylic group. While most first row transition metals complexes of diverse geometries with the Schiff bases' denticity ranging from N,O-bidentate, O,N,O-tridentate and N2O2-tetradentate amongst others have been documented, only few heavier transition metals are reported. Furthermore, these Schiff bases find promising applications in medicinal, pharmaceutical, catalytic, and analytical chemistry, especially in the seperation, identification, and detection of several metal ions and anions. In addition to these, they are used as corrosion inhibitors, as odorants, etc. Notably, the chelates more often exhibited more potency as antibacterial, antifungal, anticancer, antidiabetic, antioxidant, antioxidant, antiulcer and molluscicidal agents than the free Schiff base ligands. This review exhaustively did synthesized most significant works on the subject.

1,5-benzothiazepine has proven to be one of the most attractive and useful synthetic building blocks for clinical drugs such as diltiazem, quetiapine, thiazesim, and clentiazem. Benothiazepin generally is produced from the reaction of 2-aminothiophenols on α, and β-unsaturated carbonyl compounds. Nowadays, the replacement of toxic catalysts with green reactions especially solvent-free approaches, and microwave irradiation in place of conventional heating have been developed. The new green reaction in the synthesis of 1,5- benzothiazepine The heterocycles containing this moiety widely exist in various drugs with broad spectra of biological activities, mainly central nervous system, antimicrobial, antitumor, and enzyme inhibitors. The current minireview envisioned highlighting some recent and remarkable examples of This minireview mainly focuses on the green synthesis of 1,5-benzothiazepine diverse pharmacological properties associated with 1,5-benzothiazepine structure and covers the most relevant and recent references from 2012 to 2022.