Journal of Alloys & Compounds. Feb2022, Vol. 892, pN.PAG-N.PAG. 1p.
CHEMICAL amplification, NANOWIRES, PHOTOCATALYSIS, ELECTROCHEMISTRY, CATALYSIS, and ORGANIC chemistry
• Nanowires revealed appreciable catalytic performance in various reaction systems. • They successfully catalyze organic transformations such as coupling or reduction. • Their utility also extends to the areas of electrochemistry and photochemistry. [Display omitted] The ever-growing need for sophisticated chemical compounds drives progress in the field of catalysis. It is essential to devise new inexpensive catalytic systems to reduce reaction time, increase the yield, and put a smaller burden on the environment. The discovery of nanomaterials has breathed fresh air into this area. Extraordinary surface-to-volume ratio and various quantum effects made these materials a promising alternative to the traditional catalysts. Particularly notable results come from implementing metal species arranged in 1D, which are referred to as nanowires (NWs). In this review, we illustrate their potential to catalyze various chemical transformations in organic chemistry. We demonstrate how NWs facilitate processes such as coupling and reduction. Furthermore, we show how these species can be used in electrochemistry and photo-catalysis. Finally, having described the advances in these areas, we envision the next steps which should be taken to bring this concept to the phase of commercial implementation. [ABSTRACT FROM AUTHOR]
• Mineral-associated organic carbon (MOC) chemistry was examined with XANES. • MOC chemistry is consistent regardless of erosion rates in a mountain landscape. • MOC chemistry fails to explain MOC turnover times. Interactions between organic carbon (OC) and minerals represent a critical mechanism for stabilizing organic matter in soils. Because both mineral weathering and plant productivity are negatively affected by soil erosion, mineral-associated organic carbon (MOC) chemistry is also expected to vary with erosion intensity. Here we show that MOC chemistry, determined by carbon X-ray absorption near-edge fine structure spectroscopy (XANES), exhibits little difference across a large (10-fold) gradient in erosion-derived soil turnover times. Mineral-associated OC chemistry further fails to explain the variation in radiocarbon-based MOC turnover times. Our results suggest that soil OC longevity is largely independent of organic matter chemistry in steep mountainous landscapes where soil development is constrained by erosion. [ABSTRACT FROM AUTHOR]
Chiral organoboronates have played a critical role in organic chemistry and in the development of materials science and pharmaceuticals. Much effort has been devoted to exploring synthetic methodologies for the preparation of these compounds during the past few decades. Among the known methods, asymmetric catalysis has emerged as a practical and highly efficient strategy for their straightforward preparation, and recent years have witnessed remarkable advances in this respect. Approaches such as asymmetric borylative addition, asymmetric allylic borylation and stereospecific cross-coupling borylation, have been extensively explored and well established employing transition-metal catalysis with a chiral ligand. This review provides a comprehensive overview of transition metal-catalysed asymmetric borylation processes to construct carbon–boron, carbon–carbon, and other carbon–heteroatom bonds. It summarises a range of recent achievements in this area of research, with considerable attention devoted to the reaction modes and the mechanisms involved. [ABSTRACT FROM AUTHOR]
ALGORITHMS, MACHINE learning, ORGANIC chemistry, CHEMICAL reactions, and ORGANIC synthesis
In terms of molecules and specific reaction examples, organic chemistry features an impressive, exponential growth. However, new reaction classes/types that fuel this growth are being discovered at a much slower and only linear (or even sublinear) rate. The proportion of newly discovered reaction types to all reactions being performed keeps decreasing, suggesting that synthetic chemistry becomes more reliant on reusing the well‐known methods. The newly discovered chemistries are more complex than decades ago and allow for the rapid construction of complex scaffolds in fewer numbers of steps. We study these and other trends in the function of time, reaction‐type popularity and complexity based on the algorithm that extracts generalized reaction class templates. These analyses are useful in the context of computer‐assisted synthesis, machine learning (to estimate the numbers of models with sufficient reaction statistics), and identifying erroneous entries in reaction databases. [ABSTRACT FROM AUTHOR]
PERICYCLIC reactions, CHEMICAL reactions, RING formation (Chemistry), DIELS-Alder reaction, ORGANIC chemistry, and ATOMIC force microscopy
The Diels–Alder reaction is one of the most popular reactions in organic chemistry. However, its use in the field of on‐surface synthesis is hampered by the spatial restrictions of this cycloaddition reaction. Herein we selected a cyclic strained triyne to demonstrate an on‐surface hexadehydro‐Diels–Alder reaction in a single molecule. The reaction was studied in detail by means of atomic force microscopy (AFM) with CO‐functionalized tips. Our results pave the way to use this iconic pericyclic reaction for on‐surface synthesis, introducing the concept of atom economy in the field. [ABSTRACT FROM AUTHOR]
Golliher, Alexandra E., Tenorio, Antonio J., Cornali, Brandon M., Monroy, Erika Y., Tello-Aburto, Rodolfo, Holguin, F. Omar, and Maio, William A.
Tetrahedron. Dec2021, Vol. 102, pN.PAG-N.PAG. 1p.
SMALL molecules, FUNCTIONAL groups, ORGANIC chemistry, MOIETIES (Chemistry), and ALKYL chlorides
Enamides are a unique structural moiety in organic chemistry, present in numerous natural products and countless synthetic derivatives. In this report, we wish to disclose our recent work on the development of a novel, metal-free method to access trans -γ-chloro-enamides from the union of acrolein with secondary amides under mildly dehydrative conditions. Subsequent S N 2 displacement of the primary alkyl chloride with a variety of nucleophiles allowed access to a number of trans -γ-functionalized-enamides. In addition to a concise substrate study, two of these derivatives were further reacted to form novel triazole products, as well as di- and trienamide-containing materials. [Display omitted] [ABSTRACT FROM AUTHOR]
ORGANIC synthesis, IRON catalysts, CHEMICAL synthesis, SCIENTIFIC community, ORGANIC chemistry, and CATALYSTS
N‐containing compounds are very important molecules in nature and in the field of synthetic organic chemistry. N‐alkylation reactions play crucial role in the area of pharmaceuticals and various other industrial chemical syntheses. Iron‐catalyzed N‐alkylation reactions have attained greater acceptance among the scientific community. Environmentally benign, abundant, nontoxic, biocompatible, reusable, and inexpensive iron catalysts are gaining more attention in various research fields. Green protocols, milder reaction conditions, wide substrate scope, and so forth, signify the prominent nature of iron‐catalyzed N‐alkylation reactions. Most of the protocols are eco‐friendly and atom economic since water is the only by‐product. This review gives an overview of the advances in the Fe‐catalyzed N‐alkylation reactions covering literature up to 2021. [ABSTRACT FROM AUTHOR]
MOLECULAR clouds, METHANOL, GALACTIC center, MILKY Way, and ORGANIC chemistry
The Galactic Habitable Zone (GHZ) is a region believed hospitable for life. To further constrain the GHZ, observations have been conducted of the J = 2 â†' 1 transitions of methanol (CH3OH) at 97 GHz, toward 20 molecular clouds located in the outer Galaxy (R GC = 12.9â€"23.5 kpc), using the 12 m telescope of the Arizona Radio Observatory. Methanol was detected in 19 out of 20 observed clouds, including sources as far as R GC = 23.5 kpc. Identification was secured by the measurement of multiple asymmetry and torsional components in the J = 2 â†' 1 transition, which were resolved in the narrow line profiles observed (Î" V 1/2 âĽ 1â€"3 km sâ'1). From a radiative transfer analysis, column densities for these clouds of N tot = 0.1â€"1.5 Ă— 1013 cmâ'2 were derived, corresponding to fractional abundances, relative to H2, of f (CH3OH) âĽ 0.2â€"4.9 Ă— 10â'9. The analysis also indicates that these clouds are cold (T K âĽ 10â€"25 K) and dense (n(H2) âĽ 106 cmâ'3), as found from previous H2CO observations. The methanol abundances in the outer Galaxy are comparable to those observed in colder molecular clouds in the solar neighborhood. The abundance of CH3OH therefore does not appear to decrease significantly with distances from the Galactic Center, even at R GC âĽ 20â€"23 kpc. Furthermore, the production of methanol is apparently not affected by the decline in metallicity with galactocentric distance. These observations suggest that organic chemistry is prevalent in the outer Galaxy, and methanol and other organic molecules may serve to assess the GHZ. [ABSTRACT FROM AUTHOR]
Zonulin is a physiological modulator of intercellular tight junctions, which upregulation is involved in several diseases like celiac disease (CeD). The polyQ gliadin fragment binds to the CXCR3 chemokine receptor that activates zonulin upregulation, leading to increased intestinal permeability in humans. Here, we report a general hypothesis based on the structural connection between the polyQ sequence of the immunogenic CeD protein, gliadin, and enteric coccidian parasites proteins. Firstly, a novel interaction pathway between the parasites and the host is described based on the structural similarities between polyQ gliadin fragments and the parasite proteins. Secondly, a potential connection between coccidial infections as a novel environmental trigger of CeD is hypothesized. Therefore, this report represents a promising breakthrough for coccidian research and points out the potential role of coccidian parasites as a novel trigger of CeD that might define a preventive strategy for gluten‐related disorders in general. Also see the video abstract here: https://youtu.be/oMaQasStcFI [ABSTRACT FROM AUTHOR]
Glezer, V., Baumane, L., Turovska, B., and Ogle, J.
Journal of Solid State Electrochemistry. Dec2021, Vol. 25 Issue 12, p2717-2724. 8p.
HISTORY of science, PHYSICAL organic chemistry, SINGLE molecules, ORGANIC chemistry, HYPERFINE structure, ELECTRON paramagnetic resonance spectroscopy, PRESIDENTS, and ELECTROCHEMISTRY
Janis Stradins (10.12.1933 – 29.11.2019) was a well-known expert in molecular electrochemistry, ESR spectroscopy and physical organic chemistry, as well as in history of sciences. His main works in electrochemistry were connected with organic molecules single electron reduction and oxidation primary and secondary products studies, these species ESR spectra hyperfine structure investigations, supplying data on various organic molecules groups' reactivity, demonstrating abilities of electrochemical studies for organic compounds reaction prediction. He was ISE member, past president of Latvian Academy of Sciences, full member of European Academy of Sciences and Arts, from 2011 its Honorary Senator. [ABSTRACT FROM AUTHOR]