Chemical record最新文献

Unexpected discovery that molecules of organic dyes when they form regular structures can change dramatically their light absorption and fluorescence properties were attracting the minds of researchers for more than eight decades. The progress in investigation of this unique phenomenon described in terms of H- and J-aggregation has led to many practical applications. Here the author expresses his personal view on the dramatic story of switching this research area from empirical knowledge to that standing on strong background of molecular exciton theory. The author was a witness of some of these events and acquainted with several great personalities involved. The major trends of future developments are highlighted.

Aluminum-sulfur batteries (AlSBs) exhibit significant potential as energy storage systems due to their notable attributes, including a high energy density, cost-effectiveness, and abundant availability of aluminum and sulfur. In order to commercialize AlSBs, an understanding of their working principles is necessary. In this review, we examine the current advancements in cathodes, both in theory and practice, as well as the progress made in aqueous and nonaqueous electrolytes. We also explore the modifications made to separators and the theoretical understanding of problems associated with AlSBs. Furthermore, we discuss future research directions aimed at resolving these issues. Our aim is to summarize the current progress in AlSBs and, based on recent progress and understanding of the mechanism, help design a battery to overcome the challenges that such batteries have been facing.

Modern organic chemistry is a titan supporting and reinforcing pharmaceutical, agricultural, food and material science products. Over the past decades, the organic compounds market has been evolving to meet all the research demands. In this regard, medicinal chemistry is especially dependent on available chemical space as subtle tuning of the molecule structure is required to create a drug with relevant physicochemical properties and a remarkable activity profile. The recent rapid evolution of synthetic methodology to deploy fluorine has brought fluorinated compounds to the spotlight of MedChem community. And now unique properties of fluorine still keep fascinating more and more as its justified installation into a molecular framework has a beneficial impact on membrane permeability, lipophilicity, metabolic stability, pharmacokinetic properties, conformation, pK_a, etc. The backward influence of medicinal chemistry on organic synthesis has also changed the landscape of the latter towards new fluorinated topologies as well. Such complex relationships create a flexible and ever-changing ecosystem. Given that MedChem investigations strongly lean on the ability to reach suitable building blocks and the existence of reliable synthetic methods in this review we collected advances in the chemistry of respectful, but still enigmatic gem-difluorinated aza-heterocyclic building blocks.

In the last 10 years the interest in deep eutectic solvents (DESs) as a new class of green solvents has considerably increased. The emergence of numerous of hydrophobic DESs has stimulated intensive research into their application in extraction technologies, including sample preparation. As the properties of such systems are highly dependent on the properties of their components (hydrogen bond donors and acceptors) and can be finely tuned, DESs can be successfully used for the extraction of both metal ions and organic substances, including biomolecules. Despite the rapidly increasing number of publications on the use of DESs as an extraction medium, including review articles, information on the extraction properties of DESs in terms of their chemical composition has not yet been summarized. This review covers available literature data on the physicochemical properties of menthol-based eutectic solvents and the results of their practical application as an extraction medium. Also, the appropriateness of using the term “DES” for all mixtures with melting points lower than the melting points of their components is discussed.

Electrocatalytic water splitting is a promising alternative to produce high purity hydrogen gas as the green substitute for renewable energy. Thus, development of electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are vital to improve the efficiency of the water splitting process particularly based on transition metals which has been explored extensively to replace the highly active electrocatalytic activity of the iridium and ruthenium metals-based electrocatalysts. In situ growth of the material on a conductive substrate has also been proven to have the capability to lower down the overpotential value significantly. On top of that, the presence of substrate has given a massive impact on the morphology of the electrocatalyst. Among the conductive substrates that have been widely explored in the field of electrochemistry are the copper based substrates mainly copper foam, copper foil and copper mesh. Copper-based substrates possess unique properties such as low in cost, high tensile strength, excellent conductor of heat and electricity, ultraporous with well-integrated hierarchical structure and non-corrosive in nature. In this review, the recent advancements of HER and OER electrocatalysts grown on copper-based substrates has been critically discussed, focusing on their morphology, design, and preparation methods of the nanoarrays.

Merocyanines, thanks to their easily adjustable electronic structure, appear to be the most versatile and promising functional dyes. Their D–π–A framework offers ample opportunities for custom design through variations in both donor/acceptor end-groups and the π-conjugated polymethine chain, and leads to a broad range of practical properties, including noticeable solvatochromism, high polarizability/hyperpolarizabilities, and the ability to sensitize various physicochemical processes. Accordingly, merocyanines are applied and extensively studied in various fields, such as light-converting materials for optoelectronics, nonlinear optics, optical storage, solar cells, fluorescent probes, and antitumor agents in photodynamic therapy. This review encompasses both classical and novel more important publications on the structure–property relationships in merocyanines, with particular emphasis on the results by A.  I. Kiprianov and his followers in Institute of Organic Chemistry in Kyiv, Ukraine.

In the field of chemistry, model compounds find extensive use for investigating complex objects. One prime example of such object is the protein-ligand supramolecular interaction. Prediction the enthalpic and entropic contribution to the free energy associated with this process, as well as the structural and dynamic characteristics of protein-ligand complexes poses considerable challenges. This review exemplifies modeling approaches used to study protein-ligand binding (PLB) thermodynamics by employing pairs of conformationally constrained/flexible model molecules. Strategically designing the model molecules can reduce the number of variables that influence thermodynamic parameters. This enables scientists to gain deeper insights into the enthalpy and entropy of PLB, which is relevant for medicinal chemistry and drug design. The model studies reviewed here demonstrate that rigidifying ligands may induce compensating changes in the enthalpy and entropy of binding. Some “rules of thumb” have started to emerge on how to minimize entropy-enthalpy compensation and design efficient rigidified or flexible ligands.

Layered Double Hydroxide (LDH) is an α-modification of the M-host (M²⁺) hydroxide, in which some part of the M-host cations is replaced by M-guest cations (M³⁺ or M⁴⁺). The emerging excess positive charge is compensated by the intercalation of anions into the interlayer space, which also contains water molecules. LDHs exhibit anion exchange properties. Targeted ionic design of LDHs via combining three components (M-host, M-guest cations, intercalated anions) allows the creation of a very wide range of highly efficient electrochemical, electrocatalytic, electrochromic substances, catalysts, ion exchangers, sorbents, color pigments, pharmacological drugs, food, and cosmetic additives. In this review, the structure and areas of application of LDHs are considered from the perspective of the targeted ionic design of a substance for a specific application.

Quinazolin-4-one, its heteroanalogues, and derivatives represent an outstandingly important class of compounds in modern organic, medicinal, and pharmaceutical chemistry, as these molecular structures are noted for their wide synthetic and pharmacological potential. In the last years, ever-increasing research attention has been paid to quinazolinone derivatives bearing alkenyl and alkynyl substituents on the pyrimidinone nucleus. The original structural combination of synthetically powerful endocyclic amidine (or amidine-related) and exocyclic unsaturated moieties provides a driving force for cyclizations, which offer an efficient toolkit to construct a variety of fused pyrimidine systems with saturated N- and N,S-heterocycles. In this connection, the present review article is mainly aimed at systematic coverage of the progress in using alkenyl(alkynyl)quinazolinones and their heteroanalogues as convenient bifunctional substrates for regioselective annulation of small- and medium-sized heterocyclic nuclei. Much attention is paid to elucidating the structural and electronic effects of reagents on the regio- and stereoselectivity of the cyclizations as well as to clarifying the relevant reaction mechanisms.

In recent years, floating photovoltaic (FPV) technologies have gained more importance as a key source of clean energy, particularly in the context of providing sustainable energy to buildings. The rise of land scarcity and the need to reduce carbon emissions have made FPV systems a cost-effective solution for generating electricity. This review article aims to explore the rapidly growing trend of floating PV systems, which can be a practical solution for regions with limited land areas. The article discusses the structure of the PV modules used in FPV plants and key factors that affect site suitability choice. Moreover, the article presents various techniques for cooling and cleaning FPV to keep optimal performance and discusses feasible trends and prospects for the technology. Finally, this paper proposes the potential integration of FPV systems with other technologies to enhance energy generation efficiency and discusses other research aimed at the advancement of the technology. By examining the various features of FPV systems, this review article contributes to understanding the advantages and challenges associated with using this sustainable energy technology in different regional contexts.