Laboratory Synthesis Research Articles

Solvent-free and large-scale synthesis of SiOx/C nanocomposite with carbon encapsulation for high-performance lithium-ion battery anodes

High-capacity SiOx anodes are fatally limited by poor electrical conductivity and huge volume fluctuations. Nano-engineering can effectively extend battery life, but achieving the transformation of nanostructures from laboratory synthesis to industrial mass production still remains a great challenge. Conventional synthetic routes are plagued by harsh conditions, complex processes, and especially low yields; even if they are adopted by industrial production, the large amounts of solvents in traditional wet chemical methods will pose a potential risk of pollution and energy waste. Herein, a solvent-free and mass-producible strategy is presented to prepare SiOx/C@C nanocomposite via solvent-free sol-gel, ball milling, and carbon coating process. The production exhibits favorable powder properties for conventional LIB fabrication technology, such as narrow particle size distribution, suitable specific surface area, as well as a high yield (40.5%). The prepared SiOx/C@C anode displays a high initial coulombic efficiency (71.4%) and reversible capacity (1279 mAh g−1 at 0.1 A g−1), and a great durability (80.08% capacity retention after 1000 cycles at 1.0 A g−1). Furthermore, the superior matching performance of SiOx/C@C//LiCoO2 full-cell is also clearly demonstrated, especially the high energy density (347 Wh kg−1). This ingenious and scalable strategy will remarkably promote the commercialization of nanostructures.

RECENT DEVELOPMENT OF POLYSACCHARIDE BASED GEL: POROSITY BASED CLASSIFICATION AND A FUTURE PERSPECTIVE

Polysaccharide is one of the most ancient and vast research field among natural sustainable biopolymers and they are readily available in nature as an essential component of our daily food. Hence, distribution of the entire field into some important factor-based classification like physical structure, stability, solubility become mandatory for clear understanding of whole polysaccharide chemistry. In some past decades, scientists mainly focused on general laboratory synthesis of this biopolymers with potential applications. Then, they broadened their vision to classify polysaccharide based composite materials and hydrogels based on majorly available polysaccharides in nature. Those gels are separated from entire polysaccharide based soluble biopolymers due to their three-dimensional physical or chemical crosslinked structure and hydrophilic, polymeric frameworks. But, a more compile classification was needed for better understanding of synthetic approach for those biodegradable hydrogels and their applications. Introducing gel porosity-based classification is a novel approach facilitating to understand the gel structure. The review mainly focused the recent advancement of polysaccharide-based gels with targeted porosity. KEYWORDS: Hydrogels, biopolymers, polysaccharides, porosity

Synthesizing Laboratory and Field Experiments to Quantify Dominant Transformation Mechanisms of 2,4-Dichlorophenoxyacetic Acid (2,4-D) in Aquatic Environments.

Laboratory studies used to assess the environmental fate of organic chemicals such as pesticides fail to replicate environmental conditions, resulting in large errors in predicted transformation rates. We combine laboratory and field data to identify the dominant loss processes of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) in lakes for the first time. Microbial and photochemical degradation are individually assessed using laboratory-based microcosms and irradiation studies, respectively. Field campaigns are conducted in six lakes to quantify 2,4-D loss following large-scale herbicide treatments. Irradiation studies show that 2,4-D undergoes direct photodegradation, but modeling efforts demonstrated that this process is negligible under environmental conditions. Microcosms constructed using field inocula show that sediment microbial communities are responsible for degradation of 2,4-D in lakes. Attempts to quantify transformation products are unsuccessful in both laboratory and field studies, suggesting that their persistence is not a major concern. The synthesis of laboratory and field experiments is used to demonstrate best practices in designing laboratory persistence studies and in using those results to mechanistically predict contaminant fate in complex aquatic environments.

Efficient and synergistic degradation of fluoroquinolones by bacteria and microalgae: Design of environmentally friendly substitutes, risk regulation and mechanism analysis

Fluoroquinolones (FQs) are widely used as antimicrobial agents, and their nonbiodegradable in sewage has become an increasingly concerning. High-biochemical substitutes of FQs were designed with bacteria and microalgae as driving forces of biodegradation, and this is the first study on efficient synergistic degradation of FQs by multiple microorganisms. Among 143 designed FQ substitutes, only one was screened with high biodegradability (increased by 120.51 %), improved functional properties (genotoxicity: 13.66 %), less environmental impacts (bio-accumulation: −44.81 %), less human health and ecological risk (hepatotoxicity: −106.21 %). The complex functional protein with the synergistic degradation effect of bacteria and microalgae was constructed, which proved their synergistic degradation and realized the effect of “1 + 1 > 2″. The best risk regulation scheme determined using molecular dynamics simulation proved the degradation ability of complex functional protein and found the CIP-129 was easy to be degraded in real environment compared with CIP, and the degradation rate increased by 70.42 %. The synthesis path of CIP-129 and CIP were inferred and calculated, and the results showed the Gibbs free energies of three CIP-129 synthetic paths (40.64 a.u.; 40.61 a.u.; 40.65 a.u.) were close to the energy required for the CIP (39.43 a.u.), indicating there was no significant difference in the energy consumption of CIP-129 in laboratory synthesis.

The Gel Growth Technique—A Neglected Yet Effective Tool to Prepare Crystals of Oxysalts and Supergene Minerals

The technique of crystal growth in gels has nowadays become somewhat neglected in the scope of earth sciences, to the disadvantage of the experimental mineralogist. Even preparing an inorganic silica gel can prove a challenge to many, let alone successfully configure the entire experiment. Based not only on previous literature but also on our extensive experience, crystals of many substances, including supergene minerals as reference standards, can be successfully grown in gel, aiding in accomplishing various research goals in earth sciences. Instead of providing the reader with an overwhelming compendium of historical information and theoretical knowledge of the subject which can be found elsewhere, we presented herein a comprehensive, practically oriented guide to the understanding and successful use of the technique of crystal growth in gels, mentioning, in addition to the general principle, the numerous pitfalls which we encountered during our own use of the method, and the ways to overcome them. Despite that the procedure is nowadays used mainly for the laboratory synthesis of organic or metal-organic compounds, we believe it to be a valuable asset to any mineralogist, and often, the only way to obtain inorganic reference material of a particular mineral of interest.

Computational molecular-level prediction of heterocyclic compound–metal surface interfacial behavior

It is difficult to comprehensively understand the interfacial mechanism (IM) of the adsorption of corrosion inhibitors (CIs) on metal surfaces solely through experiments and electronic structure parameters of isolated molecules. To better understand the molecular-level IM of CIs, a combination of atomistic simulations and first-principles calculations was used to obtain reliable information on the adsorption nature and intermolecular interactions during the actual interfacial behavior. The IM and property changes of two synthesized heterocyclic sustainable-green CIs, namely 4-{[(5-nitrofuran-2-yl)methylene]amino}-5-propyl-4H-1,2,4-triazole-3-thiol (NFPT and 4-{[(5-nitrofuran-2-yl)methylene]amino}-4H-1,2,4-triazole-3-thiol (NFT), were investigated on the Fe(110) surface using first-principles density functional theory (DFT) calculations and molecular dynamics (MD) simulations. The NFPT was preferentially adsorbed through a parallel configuration with a high interaction energy (–706.12 kJ·mol−1) compared to NFT, owing to stronger chemical bonds via S, N, and O atoms with the Fe surface. Additionally, the adsorbed NFPT film effectively inhibited Fe surface corrosion owing to the small diffusion coefficient of corrosive particles in the presence of NFPT. Subsequently, the anti-corrosion performance of both CIs was validated through electrochemical methods, surface analysis, and adsorption isotherm models. The observations suggest that the combination of modern computational perspectives could efficiently design and select the best CIs before their laboratory synthesis.

Asymmetric Synthesis: A Glance at Various Methodologies for Different Frameworks

Abstract: Asymmetric reactions have made a significant advancement over the past few decades and involved the production of enantiomerically pure molecules using enantioselective organocatalysis, chiral auxiliaries/substrates, and reagents via controlling the absolute stereochemistry. The laboratory synthesis using an enantiomerically impure starting material gives a combination of enantiomers that are difficult to separate for chemists in medicine, chromatography, pharmacology, asymmetric synthesis, and studies on structure-function relationships of proteins, life sciences and mechanistic studies. This challenging step of separation can be avoided by using asymmetric synthesis. Using pharmacologically relevant scaffolds/ pharmacophores, the drug design can also be achieved using asymmetric synthesis to synthesize receptor-specific pharmacologically active chiral molecules. This approach can be used to synthesize asymmetric molecules from a wide variety of reactants using specific asymmetric conditions, which is also beneficial for the environment due to less usage and discharge of chemicals into the environment. Therefore, in this review, we have focused on the inclusive collation of diverse mechanisms in this area to encourage auxiliary studies of asymmetric reactions to develop selective, efficient, environment-friendly, and highyielding advanced processes in asymmetric reactions.

The Transformative Power of Biocatalysis in Convergent Synthesis.

Achieving convergent synthetic strategies has long been a gold standard in constructing complex molecular skeletons, allowing for the rapid generation of complexity in comparatively streamlined synthetic routes. Traditionally, biocatalysis has not played a prominent role in convergent laboratory synthesis, with the application of biocatalysts in convergent strategies primarily limited to the synthesis of chiral fragments. Although the use of enzymes to enable convergent synthetic approaches is relatively new and emerging, combining the efficiency of convergent transformations with the selectivity achievable through biocatalysis creates new opportunities for efficient synthetic strategies. This Perspective provides an overview of recent developments in biocatalytic strategies for convergent transformations and offers insights into the advantages of these methods compared to their small molecule-based counterparts.

A Laconic Review on Chalcones: Synthesis, Antimicrobial and Antioxidant activities

Chalcones and their derivatives have been an area of great interest for several researchers in recent years. Several number of research publications have been published and chalcones continue to show promising effect for novel drug investigations. Chalcone is an advantaged moiety with therapeutic importance as it comprises of receptive ketoethylenic moiety – CO–CH=CH– having a place with flavonoids. Chalcones (1, 3-Diphenyl-prop-2-en-1-one) consists of a three carbon α, β-unsaturated carbonyl system and two or more aromatic rings and acts as precursors for the biosynthesis of flavonoids in plants. The presence of a highly reactive α, β-unsaturated carbonyl system in chalcone and its derivatives is the justification for its pharmacological potencies. However, synthesis in laboratory of broad range of chalcones has also been reported. Chalcones show a wide range of pharmacological impacts like anthelmintic, antileishmanial, antifungal, antimalarial, antioxidant, antiviral, antibacterial, antiulcer, antimycobacterial, insecticidal, antigout, antihistaminic, antiprotozoal, insecticidal, anticancer, antidiabetic, anti-inflammatory, analgesic etc. Chalcones can be synthesized through Claisen–Schmidt's condensation, Heck's reaction, Aldol condensation reaction, Suzuki's reaction, from cinnamic acid, Sonogashira Isomerization Coupling reaction, Microwave assisted synthesis etc. The purpose of the present review is to centralize the various and widely employed methods of synthesis of chalcone and their various derivatives and their antimicrobial and antioxidant activities.

A Concise Review on Synthesis, Anti-inflammatory and Antioxidant Activities of Chalcone

Chalcones and their derivatives have been an area of great interest in recent years. Numbers of research publications have been published and chalcones continue to show promising effect for new drug investigations. Chalcone is an advantageous species with medicinal importance as it is consisting of highly reactive ketoethylenic system –CO–CH=CH– which belongs to flavonoids. Chalcones (1, 3-Diphenyl-2-propen-1-one) consists of a three carbon α, β-unsaturated carbonyl system and two or more aromatic rings and acts as precursors for the biosynthesis of flavonoids in plants. However, synthesis in laboratory of broad range of chalcones has also been reported. In chalcone and its derivatives, a highly reactive α, β-unsaturated carbonyl system is the major reason for their pharmacological potencies. Chalcones and their derivatives are known to show a wide range of pharmacological potencies such as anti-inflammatory, antioxidant, antileishmanial, antifungal, anticancer, antibacterial, antiulcer, antiprotozoal, antitumor, antimalarial, antidiabetic, anthelmintic, insecticidal, antigout, antihistaminic, antiviral, antimycobacterial etc. Chalcones can be prepared by Claisen–Schmidt’s condensation, Aldol condensation, Heck’s reaction, Suzuki’s reaction, Ultrasound method of synthesis, Solvent free synthesis of chalcones, One pot synthesis, Sonogashira Isomerization coupling reaction etc. The purpose of the present review is to focus on the various methods of preparation of chalcones and derivatives and their anti-inflammatory and antioxidant potencies.

Recent Progress in Two-Dimensional Materials for Electrocatalytic CO2 Reduction

Electrocatalytic CO2 reduction (ECR) is an attractive approach to convert atmospheric CO2 to value-added chemicals and fuels. However, this process is still hindered by sluggish CO2 reaction kinetics and the lack of efficient electrocatalysts. Therefore, new strategies for electrocatalyst design should be developed to solve these problems. Two-dimensional (2D) materials possess great potential in ECR because of their unique electronic and structural properties, excellent electrical conductivity, high atomic utilization and high specific surface area. In this review, we summarize the recent progress on 2D electrocatalysts applied in ECR. We first give a brief description of ECR fundamentals and then discuss in detail the development of different types of 2D electrocatalysts for ECR, including metal, graphene-based materials, transition metal dichalcogenides (TMDs), metal–organic frameworks (MOFs), metal oxide nanosheets and 2D materials incorporated with single atoms as single-atom catalysts (SACs). Metals, such as Ag, Cu, Au, Pt and Pd, graphene-based materials, metal-doped nitric carbide, TMDs and MOFs can mostly only produce CO with a Faradic efficiencies (FE) of 80~90%. Particularly, SACs can exhibit FEs of CO higher than 90%. Metal oxides and graphene-based materials can produce HCOOH, but the FEs are generally lower than that of CO. Only Cu-based materials can produce high carbon products such as C2H4 but they have low product selectivity. It was proposed that the design and synthesis of novel 2D materials for ECR should be based on thorough understanding of the reaction mechanism through combined theoretical prediction with experimental study, especially in situ characterization techniques. The gap between laboratory synthesis and large-scale production of 2D materials also needs to be closed for commercial applications.

Minimizing the Silver Free Ion Content in Starch Coated Silver Nanoparticle Suspensions with Exchange Cationic Resins.

This work describes the optimization of a methodology for the reduction of silver ions from silver nanoparticle suspensions obtained from low-yield laboratory procedures. The laboratory synthesis of silver nanoparticles following a bottom-up approach starting from silver nitrate, originates silver ions that were not reduced to their fundamental state for nanoparticles creation at the end of the process. However, it is well known that silver ions can easily influence chemical assays due to their chemical reactivity properties and can limit biological assays since they interfere with several biological processes, namely intracellular ones, leading to the death of living cells or organisms. As such, the presence of silver ions is highly undesirable when conducting biological assays to evaluate the influence of silver nanoparticles. We report the development of an easy, low-cost, and rapid methodology that is based on cation exchange resins to minimize the silver ion content in a raw suspension of silver nanoparticles while preserving the integrity of the nanomaterials. This procedure preserves the physical-chemical properties of the nanoparticles, thus allowing the purified nanoparticulate systems to be biologically tested. Different types of cationic resins were tested, and the developed methodology was optimized by changing several parameters. A reduction from 92% to 10% of free silver/total silver ratio was achieved when using the Bio-Rad 50W-X8 100–200 mesh resin and a contact time of 15 min. Filtration by vacuum was used to separate the used resin from the nanoparticles suspension, allowing it to be further reused, as well as the purified AgNPs suspension.

Enhancing the efficiency of the ruthenium catalysts in the reductive amination without an external hydrogen source

Catalytic reductive reactions are essential for laboratory and industrial-scale organic synthesis. However, the nowadays trend is the development of new, progressively more complicated reducing systems, which hinders the application of such highly efficient approaches in practice. Another way to achieve highly active systems is enhancing the activity of the earlier developed catalysts with simple structures. Herein we demonstrated a significant increase (up to 15-fold) in the catalytic activity of ruthenium catalysts in the reductive amination after the addition of iodide to the reaction mixture. Catalyst turnover numbers up to 9000 were achieved with preparative yields of the products. The plausible reasons for this effect were formulated.

A novel route for identifying starch diagenetic products in the archaeological record.

This work introduces a novel analytical chemistry method potentially applicable to the study of archaeological starch residues. The investigation involved the laboratory synthesis of model Maillard reaction mixtures and their analysis through Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS). Thus, starch from sixteen plant species were matured while reacting it with the amino acid glycine. The FTICR-MS analysis revealed > 5,300 molecular compounds, with numerous unique heteroatom rich compound classes, ranging from 20 (Zea mays) to 50 (Sorghum bicolor). These classes were investigated as repositories of chemical structure retaining source and process-specific character, linked back to botanical provenance. We discussed the Maillard reaction products thus generated, a possible pathway for the preservation of degraded starch, while also assessing diagenetic recalcitrance and adsorption potential to mineral surfaces. In some cases, hydrothermal experimentation on starches without glycine reveals that the chemical complexity of the starch itself is sufficient to produce some Maillard reaction products. The article concludes that FTICR-MS offers a new analytical window to characterize starchy residue and its diagenetic products, and is able to recognize taxonomic signals with the potential to persist in fossil contexts.

Oxygen Kinetic Isotope Effects in the Thermal Decomposition and Reduction of Ammonium Diuranate.

Oxygen stable isotopes in uranium oxides processed through the nuclear fuel cycle may have the potential to provide information about a material’s origin and processing history. However, a more thorough understanding of the fractionating processes governing the formation of signatures in real-world samples is still needed. In this study, laboratory synthesis of uranium oxides modeled after industrial nuclear fuel fabrication was performed to follow the isotope fractionation during thermal decomposition and reduction of ammonium diuranate (ADU). Synthesis of ADU occurred using a gaseous NH3 route, followed by thermal decomposition in a dry nitrogen atmosphere at 400, 600, and 800 °C. The kinetic impact of heating ramp rates on isotope effects was explored by ramping to each decomposition temperature at 2, 20, and 200 °C min–1. In addition, ADU was reduced using direct (ramped to 600 °C in a hydrogen atmosphere) and indirect (thermally decomposed to U3O8 at 600 °C, then exposed to a hydrogen atmosphere) routes. The bulk oxygen isotope composition of ADU (δ18O = −16 ± 1‰) was very closely related to precipitation water (δ18O = −15.6‰). The solid products of thermal decomposition using ramp rates of 2 and 20 °C min–1 had statistically indistinguishable oxygen isotope compositions at each decomposition temperature, with increasing δ18O values in the transition from ADU to UO3 at 400 °C (δ18OUO3 – δ18OADU = 12.3‰) and the transition from UO3 to U3O8 at 600 °C (δ18OU3O8 – δ18OUO3 = 2.8‰). An enrichment of 18O attributable to water volatilization was observed in the low temperature (400 °C) product of thermal decomposition using a 200 °C min–1 ramp rate (δ18OUO3 – δ18OADU = 9.2‰). Above 400 °C, no additional fractionation was observed as UO3 decomposed to U3O8 with the rapid heating rate. Indirect reduction of ADU produced UO2 with a δ18O value 19.1‰ greater than the precipitate and 4.0‰ greater than the intermediate U3O8. Direct reduction of ADU at 600 °C in a hydrogen atmosphere resulted in the production of U4O9 with a δ18O value 17.1‰ greater than the precipitate. Except when a 200 °C min–1 ramp rate is employed, the results of both thermal decomposition and reduction show a consistent preferential enrichment of 18O as oxygen is removed from the original precipitate. Hence, the calcination and reduction reactions leading to the production of UO2 will yield unique oxygen isotope fractionations based on process parameters including heating rate and decomposition temperature.

A Comparative Analysis of Energy and Water Consumption of Mined versus Synthetic Diamonds

In our research, we analyzed the energy and water consumption in diamond mining and laboratory synthesis operations. We used publicly available reports issued by two market leaders, DeBeers and ALROSA, to estimate water and energy use per carat of a rough diamond. The efficiency of the two most popular synthesis technologies for artificial diamonds—High-Pressure-High-Temperature (HPHT) and Microwave-assisted Chemical Vapor Deposition (M-CVD)—was examined. We found that the modern HPHT presses, with open cooling circuits, consume about 36 kWh/ct when producing gem-quality and average-sized (near-) colorless diamonds. ALROSA and DeBeers use about 96 kWh/ct and 150 kWh/ct, respectively, including all energy required to mine. Energy consumption of M-CVD processes can be different and depends on technological conditions. Our M-CVD machine is the least energy-efficient, requiring about 215 kWh/ct in the single-crystal regime, using 2.45-GHz magnetron for the support synthesis. The M-CVD methods of individual synthetic companies IIa Technology and Ekati Mine are different from our results and equal 77 and 143 kWh/ct, respectively. Water consumption for the HPHT and M-CVD methods was insignificant: approximately zero and 0.002 m3/ct, respectively, and below 0.077 m3/ct for ALROSA-mined diamonds. This study touches upon the impact of the diamond production methods used on the carbon footprint.

Implementing Machine Learning in Laboratory Synthesis by Hybrid of SVR Model and Optimization Algorithms

AbstractNumerous studies have been performed to modify ferrites to achieve the desired magnetic properties for the intended applications. Many variables with interactions between themselves are involved in modifying these properties. This study aims to provide an accurate and effective method for predicting the magnetic properties of M‐type ferrites under the influence of involved variables. For this purpose, ferrites are synthesized by doping 17 different ions and the results of the analysis of samples form the experimental data. The support vector regression (SVR) model is selected for prediction and in order to optimize hyper parameters, genetic, particle swarm optimization, and sequential minimal optimization techniques are used. Based on the comparison between the outcomes of these algorithms, the model with the best performance is used to predict coercivity and residual magnetism in M‐type magnetic ferrites. Furthermore, with the cross validation technique, the accuracy and robustness of the model designed for new samples are evaluated. The results show that the selected SVR model, with an average absolute relative error of 2% and 0.7%, is able to predict coercivity and residual magnetism, respectively. Consequently, the prediction method presented has the capability to accelerate and develop the modification of magnetic properties for different applications.

Viability and Colony Morphology Variation of Rhodococcus rhodochrous CNMN-Ac-05 in the Presence of Magnetite Nanoparticles

In recent decades the use of nanotechnologies in the remediation of xenobiotic substances has proven its effectiveness, but not its safety. Nanoparticles often accumulate in the remedied environment, having, over time, toxic effects on living organisms. In this context, research on the vital activity of microorganisms and their interaction with nanoparticles is of major importance. Aim of the research was to determine the influence of Fe3O4 nanoparticles, obtained by different ways (laboratory method and synthesis in the reactor) on the viability and colony morphology of Rhodococcus rhodochrous CNMN-Ac-05 strain. Methods. Encapsulated magnetite (Fe3O4) nanoparticles were synthesized by chemical co-precipitation method, using iron(II) sulfate and iron(III) chloride in the presence of poly-N-vinylpyrrolidone, used as a stabilizer. Fe3O4 SR (Synthesis in the Reactor) was produced in the multifunctional reactor VGR-50, at the same conditions. Cell biomass was determined on the spectrophotometer by the optical density at 540 nm,with subsequent recalculation to cell dry weight according to the calibration curve. The cell dry weight was determined by gravimetric method. The morphological features of the rhodococci colonies were described according to the standard microbiological method. Results. It was established that magnetite nanoparticles in concentrations of 1–100 mg/L were not toxic to the R. rhodochrous strain, had a positive effect on the viability of rhodococci by stimulating the growth of biomass, regardless of their concentration and the method of their synthesis. In the presence of Fe3O4 nanoparticles the population dissociated to S1, S2, R1, R2 forms, and S-R type of colonies, while the basic morphological features of R. rhodochrous colonies corresponded to type S1. Conclusions. The optimal concentration of magnetite nanoparticles, which stimulated the growth and development of R. rhodochrous was 25 mg/L for Fe3O4 and 50 mg/L Fe3O4 SR. At all concentration of Fe3O4 nanoparticles the main colony morphotype of the rhodococci was smooth S1-type; the new types of colonies represented only 0.1–0.6% of the population, and the lowest degree of variability corresponded with the highest colony-forming units index.

State-of-the-Art Biocatalysis.

The use of enzyme-mediated reactions has transcended ancient food production to the laboratory synthesis of complex molecules. This evolution has been accelerated by developments in sequencing and DNA synthesis technology, bioinformatic and protein engineering tools, and the increasingly interdisciplinary nature of scientific research. Biocatalysis has become an indispensable tool applied in academic and industrial spheres, enabling synthetic strategies that leverage the exquisite selectivity of enzymes to access target molecules. In this Outlook, we outline the technological advances that have led to the field’s current state. Integration of biocatalysis into mainstream synthetic chemistry hinges on increased access to well-characterized enzymes and the permeation of biocatalysis into retrosynthetic logic. Ultimately, we anticipate that biocatalysis is poised to enable the synthesis of increasingly complex molecules at new levels of efficiency and throughput.

Complex structures synthesized in shock processing of nucleobases – implications to the origins of life

Abstract Nucleobases are nitrogenous bases composed of monomers that are a major constituent of RNA and DNA, which are an essential part of any cellular life on the Earth. The search for nucleobases in the interstellar medium remains a major challenge, however, the recent detection of nucleobases in meteorite samples and laboratory synthesis in simulated analogue experiments have confirmed their abiotic origin and a possible route for their delivery to the Earth. Nevertheless, cellular life is based on the interacting network of complex structures, and there is substantial lack of information on the possible routes by which such ordered structures may be formed in the prebiotic environment. In the current study, we present the evidence for the synthesis of complex structures due to shock processing of nucleobases. The nucleobases were subjected to the reflected shock temperature of 3500–7000 K (estimated) and pressure of about 15–34 bar for over ~2 ms timescale. Under such extreme thermodynamic conditions, the nucleobases sample experiences superheating and subsequent cooling. Electron microscopic studies of shock processed residue show that nucleobases result in spontaneous formation of complex structures when subjected to extreme conditions of shock. These results suggest that impact shock processes might have contributed to the self-assembly of biologically relevant structures and the origin of life.