Exploiting Supramolecular Synthons in Cocrystals of Two Racetams with 4-Hydroxybenzoic Acid and 4-Hydroxybenzamide Coformers
Improved Synthesis and Coordination Behavior of 1H-1,2,3-Triazole-4,5-dithiolates (tazdt²⁻) with Ni^II, Pd^II, Pt^II and Co^III
l-Hydroxyproline-Peptide Catalysis of Aldol Additions

Journal Description

Chemistry

Chemistry is an international, peer-reviewed, open access journal on chemistry published quarterly online by MDPI.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, ESCI (Web of Science), CAPlus / SciFinder, and other databases.
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Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.6 days after submission; acceptance to publication is undertaken in 2.9 days (median values for papers published in this journal in the first half of 2023).
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Impact Factor: 2.1 (2022); 5-Year Impact Factor: 2.1 (2022)

Imprint Information Journal Flyer Open Access ISSN: 2624-8549

Latest Articles

Open AccessArticle

Synthesis of Metal Nanoparticles via Pulicaria undulata and an Evaluation of Their Antimicrobial, Antioxidant, and Cytotoxic Activities

Yasser A. El-Amier

Balsam T. Abduljabbar

Mustafa M. El-Zayat

Tushar C. Sarker

and

Ahmed M. Abd-ElGawad

Chemistry 2023, 5(4), 2075-2093; https://doi.org/10.3390/chemistry5040141 - 26 Sep 2023

Abstract

Nanoparticle engineering via plants (green synthesis) is a promising eco-friendly technique. In this work, a green protocol was applied to the preparation of silver, zinc, and selenium nanoparticle solutions supported by the extracted aerial parts of Pulicaria undulata. The formation of nanoparticles in the solution was characterized using phytochemical analysis, and UV-visible, TEM, and zeta-potential spectroscopy. In addition, various biological activities were investigated for the extract of P. undulata and the produced nanoparticles (selenium, silver, and zinc), including antioxidant, antimicrobial, and cytotoxic activities. The volatile components of the extracted constitute verified the fact that twenty-five volatile components were characterized for the majority of abundant categories for the fatty acids, esters of fatty acids (59.47%), and hydrocarbons (38.19%) of the total area. The antioxidant activity of P. undulata extract and metal nanoparticles was assessed using DPPH assay. The results indicated reduced potency for the metal nanoparticles’ solutions relative to the results for the plant extract. The cytotoxicity of the investigated samples was assessed using an MTT assay against various tumor and normal cell lines with improved cytotoxic potency of the solutions of metal nanoparticles, compared to the plant extract. The antimicrobial activity was also estimated against various bacterial and fungal species. The results confirmed amended potency for inhibiting the growth of microbial species for the solutions of metal nanoparticles when compared to the extracted aerial parts of the plant. The present study showed that green synthetized nanoparticles using P. undulata have various potential bioactivities. Full article

(This article belongs to the Special Issue Green Synthesis and Application of Metal Nanoparticles)

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Open AccessCommunication

Isoselenazole Synthesis by Rh-Catalyzed Direct Annulation of Benzimidates with Sodium Selenite

Qing-Feng Xu-Xu

Yuji Nishii

and

Masahiro Miura

Chemistry 2023, 5(4), 2068-2074; https://doi.org/10.3390/chemistry5040140 - 23 Sep 2023

Abstract

Organoselenium compounds have attracted significant research interest because of their potent therapeutic activities and indispensable applications in the organic chemistry field. The selenation reactions conventionally rely on the use of sensitive Se reagents; thus, new synthetic methods with improved efficiency and operational simplicity have recently been of particular interest. In this manuscript, we report a Rh-catalyzed direct selenium annulation using tractable sodium selenite (Na₂SeO₃) as the limiting reagent. The selenite species was converted to highly electrophilic SeO(OBz)₂ in situ upon treatment with Bz₂O, thereby undergoing C–H/N–H double nucleophilic selenation. A series of benzimidates successfully underwent selenation under mild reaction conditions to afford isoselenazole derivatives. Full article

(This article belongs to the Special Issue Catalytic Organic Synthesis—a Special Issue in Honor of Professor Masahiro Miura)

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Open AccessArticle

Direct Aniline Formation with Benzene and Hydroxylamine

Ningyu Liu

Matthew D. Sleck

and

William D. Jones

Chemistry 2023, 5(4), 2056-2067; https://doi.org/10.3390/chemistry5040139 - 23 Sep 2023

Abstract

A single-step method for aniline formation was examined. Using a vanadate catalyst with an iron oxide co-catalyst and hydroxylamine hydrochloride as the amine source, an up to 90% yield of aniline was obtained with high selectivity. Further study showed that the overall reaction was pseudo-second order in terms of hydroxylamine concentration. Regioselective H-D exchange experiments suggest that the C-N bond formation step occurs via an irreversible electrophilic pathway. Based on all of the key observations, a mechanism is proposed. Full article

(This article belongs to the Special Issue Catalytic Organic Synthesis—a Special Issue in Honor of Professor Masahiro Miura)

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Open AccessArticle

In Pursuit of Next Generation N-Heterocyclic Carbene-Stabilized Copper and Silver Precursors for Metalorganic Chemical Vapor Deposition and Atomic Layer Deposition Processes

Ilamparithy Selvakumar

Nils Boysen

Marco Bürger

and

Anjana Devi

Chemistry 2023, 5(3), 2038-2055; https://doi.org/10.3390/chemistry5030138 - 20 Sep 2023

Abstract

Volatile, reactive, and thermally stable organometallic copper and silver complexes are of significant interest as precursors for the metalorganic chemical vapor deposition (MOCVD) and atomic layer deposition (ALD) of ultra-thin metallic films. Well-established Cu^I and Ag^I precursors are commonly stabilized by halogens, phosphorous, silicon, and oxygen, potentially leading to the incorporation of these elements as impurities in the thin films. These precursors are typically stabilized by a neutral and anionic ligand. Recent advancements were established by the stabilization of these complexes using N-heterocyclic carbenes (NHCs) as neutral ligands. To further enhance the reactivity, in this study the anionic ligand is sequentially changed from β-diketonates to β-ketoiminates and β-diketiminates, yielding two new Cu^I and two new Ag^I NHC-stabilized complexes in the general form of [M(NHC) (R)] (M = Cu, Ag; R = β-ketoiminate, β-diketiminate). The synthesized complexes were comparatively analyzed in solid, dissolved, and gaseous states. Furthermore, the thermal properties were investigated to assess their potential application in MOCVD or ALD. Among the newly synthesized complexes, the β-diketiminate-based [Cu(tBuNHC) (NacNacMe)] was identified to be the most suitable candidate as a precursor for Cu thin film deposition. The resulting halogen-, oxygen-, and silicon-free Cu^I and Ag^I precursors for MOCVD and ALD applications are established for the first time and set a new baseline for coinage metal precursors. Full article

(This article belongs to the Special Issue Commemorating 150 Years of Justus von Liebig’s Legacy)

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Open AccessArticle

High Thermal Stability of Enzyme-MOF Composites at 180 °C

Shitong Cui

and

Jun Ge

Chemistry 2023, 5(3), 2025-2037; https://doi.org/10.3390/chemistry5030137 - 19 Sep 2023

Abstract

Encapsulating enzymes in a tailored scaffold is of great potential in industrial enzymatic catalysis, which can enhance the stability of enzymes thus expanding their applications. Metal–organic frameworks (MOFs) are emerging as promising candidates for enzyme encapsulation due to their precise pore structure, ease of synthesis and good biocompatibility. Despite the fact that enzymes encapsulated in MOFs can obtain enhanced stability, there has been little discussion about the thermal stability of enzyme-MOF composites in solid state under extremely high temperatures. Herein, we fabricated the enzyme-MOF composites, CALB-ZIF-8, via a convenient coprecipitation method in aqueous solution, which exhibited good thermal stability at 180 °C. It was found that the activity of CALB encapsulated in ZIF-8 retained nearly ~80% after heating for 10 min at 180 °C. A finite element method was applied to investigate the heat transfer process within a ZIF-8 model, indicating that the air filled in cavities of ZIF-8 played a significant role in hindering the heat transfer and this may be an important reason for the outstanding thermal stability of CALB-ZIF-8 at 180 °C, which paves a new path for expanding the industrial application of enzyme-MOF composites. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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Open AccessArticle

The Antimicrobial and Mosquitocidal Activity of Green Magnesium Oxide Nanoparticles Synthesized by an Aqueous Peel Extract of Punica granatum

Amr Fouda

Khalid S. Alshallash

Mohammed I. Alghonaim

and

Chemistry 2023, 5(3), 2009-2024; https://doi.org/10.3390/chemistry5030136 - 12 Sep 2023

Abstract

An aqueous extract of Punica granatum peel was used as a biocatalyst for magnesium oxide nanoparticle (MgO-NP) synthesis, which was characterized via UV-Vis spectroscopy, TEM, EDX, FT-IR, XRD, DLS, and zeta potential. Data showed the efficacy of the plant aqueous extract in forming spherical, crystalline-nature, well-arranged MgO-NPs with sizes in the range of 10–45 nm with average sizes of 24.82 ± 8.85 nm. Moreover, EDX analysis revealed that the highest weight and atomic percentages were recorded for Mg and O ions. The green synthesized MgO-NPs showed antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, E. coli, Pseudomonas aeruginosa, and Candida albicans in a concentration-dependent manner with clear zones in the range of 8.7 ± 0.6 to 19.7 ± 0.5 mm with various concentrations. Also, the MIC value was varied to be 25 µg mL⁻¹ for Gram-negative bacteria, B. subtilis, and C. albicans and 50 µg mL⁻¹ for S. aureus. Moreover, MgO-NPs showed high activity against the 3rd-instar larvae of Culex quinquefasciatus. The mortality percentages were concentration- and time-dependent. Data analysis showed that the highest mortality was 88.3 ± 3.2%, attained at a concentration of 100 µg mL⁻¹ after 72 h. Also, all originated pupae were malformed and did not hatch to adults, with mortality percentages of 100% at all concentrations. Overall, the P. granatum-mediated MgO-NPs showed promising activity in inhibiting the growth of pathogenic microbes and the hatching of C. quinquefasciatus larvae to adults. Full article

(This article belongs to the Special Issue Recent Advances in Antimicrobial Materials)

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Open AccessArticle

Expanding Heteroaromatic and 2-Aminosugar Chemical Space Accessible from the Biopolymer Chitin

and

Chemistry 2023, 5(3), 1998-2008; https://doi.org/10.3390/chemistry5030135 - 09 Sep 2023

Abstract

Herein, we report the expansion of chemical space available from chitin, accessible via the biogenic N-platforms 3A5AF, M4A2C, and di-HAF. The biologically active heteroaromatics furo[3,2-d]pyrimidin-4-one and furo[3,2-d]pyrimidin-4-amine can be selectively accessed from 3A5AF and M4A2C, respectively. The chiral pool synthon di-HAF is a viable substrate for Achmatowicz rearrangement, providing streamlined access to 2-aminosugars possessing a versatile hydroxymethyl group at C5. Full article

(This article belongs to the Special Issue Green Chemistry—a Themed Issue in Honor of Professor James Clark)

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Open AccessCommunication

Solid State Fabrication of Copper Nanoclusters and Supraparticles

Rui Wang

Yunyun Zheng

and

Yunsheng Xia

Chemistry 2023, 5(3), 1990-1997; https://doi.org/10.3390/chemistry5030134 - 06 Sep 2023

Abstract

In this study, we present solid state processes for the fabrication of copper nanoclusters (NCs) and hierarchical supraparticles (SPs). To achieve this, copper salt and thiols are mixed and are then grinded for 10–15 min, and the nano-products are thereby obtained. Interestingly, it was found in this study that the formation of the NCs or SPs is completely dependent on the grinding methods that are used: with mechanical grinding, the products are several nanometer-sized NCs, whereas manual grinding in an agate mortar can obtain Cu SPs with diameters as low as 10 nm all the way up to 200 nm. The photoluminescence emission wavelength of the nano-products is located at ~680 nm. The Stokes shift of the obtained nanomaterials is more than 300 nm. The emission quantum yields of the Cu NCs and SPs are as high as 47.5% and 63%, respectively. Due to their facile fabrication processes and their favorable optical properties, the two as-prepared types of copper nano-materials exhibit great potential for bio-imaging and bio-sensing applications. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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Open AccessArticle

Syntheses, Crystal and Electronic Structures of Rhodium and Iridium Pyridine Di-Imine Complexes with O- and S-Donor Ligands: (Hydroxido, Methoxido and Thiolato)

and

Chemistry 2023, 5(3), 1961-1989; https://doi.org/10.3390/chemistry5030133 - 05 Sep 2023

Abstract

The syntheses of new neutral square-planar pyridine di-imine rhodium and iridium complexes with O- and S-donor (OH, OR, SH, SMe and SPh) ligands along with analogous cationic compounds are reported. Their crystal and electronic structures are investigated in detail with a focus on the non-innocence/innocence of the PDI ligand. The oxidation states of the metal centers were analyzed by a variety of experimental (XPS and XAS) and theoretical (LOBA, EOS and OSLO) methods. The dπ-pπ interaction between the metal centers and the π-donor ligands was investigated by theoretical methods and revealed the partial multiple-bond character of the M-O,S bonds. Experimental support is provided by a sizable barrier for the rotation about the Ir-S bond in the methyl thiolato complex and confirmed by DFT and LNO-CCSD(T) calculations. This was corroborated by the high Ir-O and Ir-S bond dissociation enthalpies calculated at the PNO-CCSD(T) level. Full article

(This article belongs to the Special Issue Commemorating 150 Years of Justus von Liebig’s Legacy)

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Open AccessArticle

Encapsulation of Ciprofloxacin into a Cyclodextrin Polymer Matrix: The Complex Formation with Human Serum Albumin and In Vitro Studies

Anna A. Skuredina

Tatiana Yu. Kopnova

Natalya G. Belogurova

and

Elena V. Kudryashova

Chemistry 2023, 5(3), 1942-1960; https://doi.org/10.3390/chemistry5030132 - 01 Sep 2023

Abstract

Here, we propose a drug delivery system for ciprofloxacin (CF) based on cyclodextrin (CD) polymer. We obtained a 3D matrix system with encapsulated drug molecules by crosslinking CF+CD non-covalent complexes with 1.6-hexamethylene isocyanate. The obtained polycarbamide (MAX-system) represents particles (~225 nm in diameter) that demonstrate CF’s sustained release. We investigated how the carrier affects the drug’s interaction with the biological macromolecule human serum albumin (HSA) and CF’s antibacterial properties. Compared to a binary CF–HSA system, CD decreases CF’s binding efficiency to HSA by two times, whereas CF encapsulation in a polymer matrix doubles the Ka value and prevents protein aggregation. The changes in HSA’s secondary structure indicate no alterations in the main mechanism of complex formation between CF and HSA in the presence of both CD-based carriers. CD as well as MAX systems practically do not change CF’s activity against E. coli and B. subtilis, but for MAX systems, prolonged action is realized due to CF’s sustained release. We believe that our findings are important for the further development of new, efficient drug forms. Full article

(This article belongs to the Section Medicinal Chemistry)

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Open AccessReview

Antioxidant Determining Using Electrochemical Method

and

Chemistry 2023, 5(3), 1921-1941; https://doi.org/10.3390/chemistry5030131 - 01 Sep 2023

Abstract

Antioxidants are very beneficial for health as they protect the body from the effects of free radicals on various degenerative diseases caused by food contamination, air pollution, sunlight, etc. In general, methods for measuring the capacity of antioxidants generally use accurate methods such as spectrophotometry and chromatography. Still, this takes time, accurate sample preparation, and must be performed in a laboratory with particular expertise. Therefore, a new, more practical method needs to be developed for determining antioxidants, namely the electrochemical method. The electrochemical method is a promising method to develop because it comes with several advantages, including high sensitivity and fast response. The electrochemical method discussed in this article reviews sensors, biosensors, and nanosensors. This paper comprehensively analyzes contemporary developments in electrochemical biosensor techniques and antioxidant evaluation methodologies. The discussion centers on utilizing multiple biosensors. Electrochemical biosensors have been determined to be prevalent in analyzing food quality, assessing active factor functionality, and screening practical components. The present study outlines the difficulties linked with electrochemical bio-sensor technology and provides insights into the potential avenues for future research in this domain. Full article

(This article belongs to the Section Electrochemistry)

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Open AccessCommunication

Structure, Stability and Binding Properties of Collagen-Binding Domains from Streptococcus mutans

and

Chemistry 2023, 5(3), 1911-1920; https://doi.org/10.3390/chemistry5030130 - 01 Sep 2023

Abstract

Collagen-binding proteins (CBP), Cnm and Cbm, from Streptococcus mutans are involved in infective endocarditis caused by S. mutans because of their collagen-binding ability. In this study, we focused on the collagen-binding domain (CBD), which is responsible for the collagen-binding ability of CBP, and analyzed its structure, binding activity, and stability using CBD domain variants. The CBD consists of the N1 domain, linker, N2 domain, and latch (N1-N2~) as predicted from the amino acid sequences. The crystal structure of the Cnm/CBD was determined at a 1.81 Å resolution. N1_linker_N2 forms a ring structure that can enfold collagen molecules, and the latch interacts with N1 to form a ring clasp. N1 and N2 have similar immunoglobulin folds. The collagen-binding activities of Cbm/CBD and its domain variants were examined using ELISA. N1-N2~ bound to collagen with K_D = 2.8 μM, and the latch-deleted variant (N1-N2) showed weaker binding (K_D = 28 μM). The linker-deleted variant (N1N2~) and single-domain variants (N1 and N2) showed no binding activity, whereas the domain-swapped variant (N2-N1~) showed binding ability, indicating that the two N-domains and the linker are important for collagen binding. Thermal denaturation experiments showed that N1-N2 was slightly less stable than N1-N2~, and that N2 was more stable than N1. The results of this study provide a basis for the development of CBD inhibitors and applied research utilizing their collagen-binding ability. Full article

(This article belongs to the Section Crystallography)

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Open AccessReview

Self-Assembled DNA Nanospheres: Design and Applications

and

Chemistry 2023, 5(3), 1882-1910; https://doi.org/10.3390/chemistry5030129 - 29 Aug 2023

Abstract

Self-assembled DNA nanospheres, as versatile and ideal vehicles, have offered new opportunities to create intelligent delivery systems for precise bioimaging and cancer therapy, due to their good biostability and cell permeability, large loading capacity, and programmable self–assembly behaviors. DNA nanospheres can be synthesized by the self–assembly of Y–shaped DNA monomers, ultra–long single-stranded DNA (ssDNA), and even metal–DNA coordination. Interestingly, they are size–controllable by varying some parameters including concentration, reaction time, and mixing ratio. This review summarizes the design of DNA nanospheres and their extensive biomedical applications. First, the characteristics of DNA are briefly introduced, and different DNA nanostructures are mentioned. Then, the design of DNA nanospheres is emphasized and classified into three main categories, including Y–shaped DNA unit self-assembly by Watson–Crick base pairing, liquid crystallization and the dense packaging of ultra–long DNA strands generated via rolling circle amplification (RCA), and metal–DNA coordination–driven hybrids. Meanwhile, the advantages and disadvantages of different self–assembled DNA nanospheres are discussed, respectively. Next, the biomedical applications of DNA nanospheres are mainly focused on. Especially, DNA nanospheres serve as promising nanocarriers to deliver functional nucleic acids and drugs for biosensing, bioimaging, and therapeutics. Finally, the current challenges and perspectives for self-assembled DNA nanospheres in the future are provided. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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Open AccessArticle

Insight into the Adsorption Behavior of Carbon Nanoparticles Derived from Coffee Skin Waste for Remediating Water Contaminated with Pharmaceutical Ingredients

Mutaz Salih

Babiker Y. Abdulkhair

and

Mansour Alotaibi

Chemistry 2023, 5(3), 1870-1881; https://doi.org/10.3390/chemistry5030128 - 24 Aug 2023

Abstract

Coffee skins, a cheap, agricultural waste, were carbonized in a tubular furnace under a nitrogen stream and then ball milled to fabricate coffee skin-carbon-nanoparticles (CCNPs). SEM showed 35.6–41.6 nm particle size. The 26.64 and 43.16 peaks in the XRD indicated a cubic graphite lattice. The FT-IR broadband revealed a 2500–3500 cm⁻¹ peak, suggesting an acidic O-H group. CCNPs possessed a type-H3-loop in the N₂-adsorption-desorption analysis, with a surface of 105.638 m² g⁻¹. Thereafter, CCNPs were tested for ciprofloxacin (CPXN) adsorption, which reached equilibrium in 90 min. CCNPs captured 142.6 mg g⁻¹ from 100 mg L⁻¹ CPXN, and the 5:12 sorbent mass-to-solution volume ratio was suitable for treating up to 75 mg L⁻¹ contamination. The q_t dropped from 142.6 to 114.3 and 79.2 mg g⁻¹ as the temperature rose from 20 °C to 35 °C and 50 °C, respectively, indicating exothermic adsorption. CPXN removal efficiency decreased below pH 5.0 and above pH 8.0. Kinetically, CPXN adsorption fits the second-order model and is controlled by the liquid-film mechanism, indicating its preference for the CCNPs’ surface. The adsorption agreement with the liquid-film and Freundlich models implied the ease of CPXN penetration into the CCNP inner shells and the multilayered accumulation of CPXN on the CCNPs’ surface. The negative ∆H° and ∆G° revealed the exothermic nature and spontaneity of CPXN adsorption onto the CCNP. The CCNPs showed an efficiency of 95.8% during four consecutive regeneration-reuse cycles with a relative standard deviation (RSD) of 3.1%, and the lowest efficiency in the fourth cycle was 92.8%. Full article

(This article belongs to the Special Issue Low-Cost Water Treatment - New Materials and New Approaches)

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Open AccessArticle

Optimization of Enzymatic Synthesis of D-Glucose-Based Surfactants Using Supported Aspergillus niger Lipase as Biocatalyst

Alexis Spalletta

Nicolas Joly

and

Patrick Martin

Chemistry 2023, 5(3), 1855-1869; https://doi.org/10.3390/chemistry5030127 - 23 Aug 2023

Abstract

Surfactants are amphiphilic molecules with the ability to modify the surface tension between two surfaces. They can be obtained by various methods, the main one being synthetic, from petroleum-based substrates. Their universal use in a wide range of fields has created a global market and, consequently, ecological, and economic expectations for their production. Biocatalyzed processes, involving enzymes, can address this objective with processes complying with the principles of green chemistry: energy saving, product selectivity, monodispersity, and reduction in the use of solvents, with energy eco-efficiency. For example, fatty-acid carbohydrate esters are biobased surfactants that can be synthesized by lipases. In this work, we were interested in the synthesis of D-glucose lauric ester, which presents interesting properties described in the literature, with Aspergillus niger lipase, rarely described with sugar substrates. We optimized the synthesis for different parameters and reaction media. This lipase appeared to be highly selective for 6-O-lauroyl-D-glucopyranose. However, the addition of DMSO (dimethyl sulfoxide) as a co-solvent displays a duality, increasing yields but leading to a loss of selectivity. In addition, DMSO generates more complex and energy-intensive purification and processing steps. Consequently, a bio-sourced alternative as co-solvent with 2MeTHF3one (2-methyltetrahydrofuran-3-one) is proposed to replace DMSO widely described in the literature. Full article

(This article belongs to the Special Issue Green Chemistry—a Themed Issue in Honor of Professor James Clark)

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Open AccessArticle

Tris(3-nitropentane-2,4-dionato-κ2 O,O′) Complexes as a New Type of Highly Energetic Materials: Theoretical and Experimental Considerations

Danijela S. Kretić

Ivana S. Veljković

and

Dušan Ž. Veljković

Chemistry 2023, 5(3), 1843-1854; https://doi.org/10.3390/chemistry5030126 - 18 Aug 2023

Abstract

Decreasing the sensitivity towards detonation of high-energy materials (HEMs) is the ultimate goal of numerous theoretical and experimental studies. It is known that positive electrostatic potential above the central areas of the molecular surface is related to high sensitivity towards the detonation of high-energy molecules. Coordination compounds offer additional structural features that can be used for the adjustment of the electrostatic potential values and sensitivity towards detonation of this class of HEM compounds. By a careful combination of the transition metal atoms and ligands, it is possible to achieve a fine-tuning of the values of the electrostatic potential on the surface of the chelate complexes. Here we combined Density Functional Theory calculations with experimental data to evaluate the high-energy properties of tris(3-nitropentane-2,4-dionato-κ2 O,O′) (nitro-tris(acetylacetonato)) complexes of Cr(III), Mn(III), Fe(III), and Co(III). Analysis of the Bond Dissociation Energies (BDE) of the C-NO₂ bonds and Molecular Electrostatic Potentials (MEP) showed that these compounds may act as HEM molecules. Analysis of IR spectra and initiation of the Co(AcAc-NO₂)₃ complex in the open flame confirmed that these compounds act as high-energy molecules. The measured heat of combustion for the Co(AcAc-NO₂)₃ complex was 14,133 J/g, which confirms the high-energy properties of this compound. The results also indicated that the addition of chelate rings may be used as a new tool for controlling the sensitivity towards the detonation of high-energy coordination compounds. Full article

(This article belongs to the Section Theoretical Chemistry)

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Open AccessArticle

A Ratiometric Fluorescent Probe for pH Measurement over a Wide Range Composed of Three Types of Fluorophores Assembled on a DNA Scaffold

Eiji Nakata

Khongorzul Gerelbaatar

and

Chemistry 2023, 5(3), 1832-1842; https://doi.org/10.3390/chemistry5030125 - 17 Aug 2023

Abstract

The desirable properties of the sophisticated fluorescent pH probe are ratiometric detection properties and a wide detection range. In this study, three types of fluorophores with different fluorescence properties were assembled on a DNA origami nanostructure. DNA nanostructure has the advantage of being a scaffold that can assemble different types of fluorophores with control over their number and position. The defined number of three different fluorophores, i.e., pH-sensitive fluorescein (CF) and Oregon Green (OG), and pH-insensitive tetramethylrhodamine (CR), assembled on the DNA scaffold provided a ratiometric fluorescent pH probe with a wide pH detection range that could cover the variation of intracellular pH. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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Open AccessReview

DNA Nanotechnology-Empowered Fluorescence Imaging of APE1 Activity

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Chemistry 2023, 5(3), 1815-1831; https://doi.org/10.3390/chemistry5030124 - 17 Aug 2023

Abstract

Apurinic/apyrimidinic endonuclease 1 (APE1), also known as redox factor-1 (Ref-1), is a multifunctional protein that exists widely in living organisms. It can specifically recognize and cleave the DNA in apurinic/apyrimidinic (AP) sites in the base excision repair (BER) pathway, as well as regulate the expression of genes to activate some transcription factors. The abnormal expression and disruptions in the biological functions of APE1 are linked to a number of diseases, including inflammation, immunodeficiency, and cancer. Hence, it is extremely desired to monitor the activity of APE1, acquiring a thorough understanding of the healing process of damaged DNA and making clinical diagnoses. Thanks to the advent of DNA nanotechnology, some nanodevices are used to image the activity of APE1 with great sensitivity and simplicity. In this review, we will summarize developments in DNA-nanotechnology-empowered fluorescence imaging in recent years for APE1 activity according to different types of DNA probes, which are classified into linear DNA probes, composite DNA nanomaterials, and three-dimensional (3D) DNA nanostructures. We also highlight the future research directions in the field of APE1 activity imaging. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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Open AccessArticle

Porous Natural Diamond with Embedded Metal (Pt_0.50–Co_0.50)

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Chemistry 2023, 5(3), 1804-1814; https://doi.org/10.3390/chemistry5030123 - 14 Aug 2023

Abstract

Natural diamond crystals with a highly porous surface were used as substrates for synthesizing single-phase bimetallic Pt–Co nanoparticles at temperatures of 500 °C and 800 °C. The metal nanoparticles inside the pores were determined to take the form of single-phase Pt_0.50Co_0.50 solid solutions with different degrees of superstructure ordering. A detailed characterization of both nanoalloys revealed a tetragonal symmetry with a space group, P4/mmm. For the sample obtained at 500 °C, the lattice parameters were a = 2.673(2), c = 3.735(3) Å, and c/a = 1.397(1); for the samples obtained at 800 °C, the parameters were—a = 2.688(2), c = 3.697(3) Å, and c/a = 1.375(1). Within the experimental parameters, no significant chemical interaction of the diamond with the Pt–Co particles was identified. The results demonstrate a strong anchoring effect of the metallic material within the etching pores. The successful synthesis of bimetallic Pt–Co particles embedded inside the caverns can facilitate a study of their magnetic properties. The presence of Pt–Co in specific diamond compositions can also be used for marking diamond crystals as a means for their subtle identification, as well as confirming the possibility of capturing significant amounts of metal along with diamonds during their dissolution in the deep Earth. Full article

(This article belongs to the Section Inorganic Materials and Polymers)

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Open AccessReview

Recent Advances in Dynamic DNA Nanodevice

Qin Fan

Linzi Yang

and

Jie Chao

Chemistry 2023, 5(3), 1781-1803; https://doi.org/10.3390/chemistry5030122 - 10 Aug 2023

Abstract

DNA nanotechnology has been widely used to fabricate precise nanometer-scale machines. In particular, dynamic DNA nanodevices have demonstrated their ability to mimic molecular motions and fluctuations in bion-anomic systems. The elaborately designed DNA nanomachines can conduct a variety of motions and functions with the input of specific commands. A dynamic DNA nanodevice with excellent rigidity and unprecedented processability allows for structural transformation or predictable behavior, showing great potential in tackling single-molecule sensing, drug delivery, molecular systems, and so on. Here, we first briefly introduce the development history of DNA nanotechnology. The driving energy of dynamic DNA nanomachines is also discussed with representative examples. The motor pattern of DNA nanomachines is classified into four parts including translational motion, shear motion, 360° rotation, and complex motion. This review aims to provide an overview of the latest reports on the dynamic DNA nanomachine and give a perspective on their future opportunities. Full article

(This article belongs to the Special Issue Functional Biomolecule-Based Composites and Nanostructures: Current Developments and Applications—a Themed Issue in Honor of Prof. Dr. Itamar Willner)

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