ChemInform Abstract: Syntheses,Structures, Physical Properties,and Electronic Structures of Ba2MLnTe5 (M: Ga and Ln: Sm,Gd, Dy,Er, Y; M: In and Ln: Ce,Nd, Sm,Gd, Dy,Er, Y).

The title compounds are synthesized by solid state reactions of BaTe, Ga₂Te₃ or In₂Te₃, Ln, and Te (1273—1323 K, 20—48 h) and characterized by single crystal XRD, diffuse reflectance spectroscopy, magnetic susceptibility measurements, second harmonic generation measurements, and DFT electronic structure calculations.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

Pyrenes,Peropyrenes, and Teropyrenes: Synthesis,Structures, and Photophysical Properties

The design of a relatively simple and efficient method to extend the π‐conjugation of readily available aromatics in one‐dimension is of significant value. In this paper, pyrenes, peropyrenes, and teropyrenes were synthesized through a double or quadruple benzannulation reaction of alkynes promoted by Brønsted acid. This novel method does not involve cyclodehydrogenation (oxidative aryl–aryl coupling) to arrive at the newly incorporated large arene moieties. All of the target compounds were synthesized in moderate to good yields and were fully characterized with the structures unambiguously confirmed by X‐ray crystallography. As expected, photophysical characterization clearly shows increasing red‐shifts as a function of extended conjugation within the fused ring systems.     

Borinium, borenium, and boronium ions: synthesis, reactivity, and applications

Boron cations are elusive and highly electrophilic species that play a key role in the chemistry of boron. Despite early interest in the chemistry of boron cations, until recently they have largely remained chemical curiosities. However, hints at harnessing their potential as potent electrophiles have begun to appear and developments in weakly coordinating anion technology suggest that this is an area of research that is ripe for exploration. It has been nearly 20 years since the last major review on boron cations; herein we summarize the progress in the area since that time.     

Biosurfactants: Formulations,properties, and applications

In this review, we attempt to give an overview on the recent progress made on biosurfactants, surface-active biomolecules produced by microorganisms, which are a sustainable alternative to synthetic surfactants. Different biosurfactants, their production techniques, and their physical and chemical properties are discussed. There is a focus on recent studies related to surface properties and rheology of biosurfactants, both being properties which affect their ability to take part in a stable formulation. Biosurfactants can have applications in multiple different industrial sectors, such as agriculture, medicine, personal care, food, petroleum, etc. The specific properties important for applications in these sectors are discussed in detail.     

Tetrodotoxin: History,Biology, and Synthesis

This review provides a comprehensive coverage of the history, biology and chemistry of tetrodotoxin (TTX). It traces the origin of this remarkable molecule all the way back to the ancient Chinese medicine records. The discovery of biological activity, isolation, and a brief overview of structure elucidation are summarized. Next, the biology of TTX is discussed, primarily in the context of its activity in the sodium channels, its anesthetic properties, and its potential use in cancer treatment or drug addiction. Biosynthesis of TTX is covered before the discussion of the total syntheses. All total, formal or partial syntheses are covered but those total syntheses that have been discussed in previous reviews are only briefly summarized. Finally, the synthesis of natural and unnatural derivatives is surveyed, and a conclusion and outlook are provided for this very extensive field of endeavor. To the best of our knowledge the literature coverage is complete up to December 2018.     

GROMACS: fast, flexible, and free

This article describes the software suite GROMACS (Groningen MAchine for Chemical Simulation) that was developed at the University of Groningen, The Netherlands, in the early 1990s. The software, written in ANSI C, originates from a parallel hardware project, and is well suited for parallelization on processor clusters. By careful optimization of neighbor searching and of inner loop performance, GROMACS is a very fast program for molecular dynamics simulation. It does not have a force field of its own, but is compatible with GROMOS, OPLS, AMBER, and ENCAD force fields. In addition, it can handle polarizable shell models and flexible constraints. The program is versatile, as force routines can be added by the user, tabulated functions can be specified, and analyses can be easily customized. Nonequilibrium dynamics and free energy determinations are incorporated. Interfaces with popular quantum-chemical packages (MOPAC, GAMES-UK, GAUSSIAN) are provided to perform mixed MM/QM simulations. The package includes about 100 utility and analysis programs. GROMACS is in the public domain and distributed (with source code and documentation) under the GNU General Public License. It is maintained by a group of developers from the Universities of Groningen, Uppsala, and Stockholm, and the Max Planck Institute for Polymer Research in Mainz. Its Web site is http://www.gromacs.org.     

Azacalixarenes: Synthesis, Complexation, and Structures

Azacalixarenes, which have various N-bound side arms, were synthesized in aone-pot manner in satisfactory yields. Their structures in the solid and solution wereelucidated by the NMR spectroscopic method and X-ray crystallographic analyses.Some of them complexed with metal ions (alkali metal, lanthanide, and uranyl ions)under neutral conditions. By the functionalization of the side arms, a wide variety ofapplications is expected.     

Diiminoisoindoline: tautomerism, conformations, and polymorphism

Two polymorphs of the industrially important compound diiminoisoindoline occur in the amino tautomeric form as a conformational isomorph with a 1 : 1 mixture of the syn- and anti-isomers, and a conformational polymorph containing only the syn-isomer.     

Cannabinoids: structures,effects, and classification

The data on the chemical structures, biological effects, and use of cannabinoids on the illegal market of new psychoactive substances were generalized. An extended classification comprising new classes, groups, and subgroups of cannabinoids was proposed for better representation of their structural variety. The emergence of new synthetic cannabinoids which belong to the groups of cycloalkanecarbonylindoles, indole- and indazole-3-carboxamides, and indoleand indazole-3-carboxylates is closely associated with the market of new psychoactive substances.     

Biopolymers: origin, chemistry, and biology

A brief statement concerning the way in which biopolymers may have originated in the nonbiological world is made, including experimental evidence. This also includes a discussion of such matters as the way in which the code might have originated, that is, the relationship between polypeptides and polynucleotides as well as the secondary and tertiary structure resulting from the primary structure determination. The importance of the interaction of biopolymers with lipids for the formation of limiting membranes, leading to the formation of cells and other self-organizing cellular type organelles, is discussed. Thus, the second critical physical-chemical problem for cellular organization, namely, the biopolymer-lipid interaction, is now coming under scrutiny, both in terms of synthetic systems as well as natural ones.     

Tetrahedranyllithium: synthesis, characterization, and reactivity

The first representative of stable tetrahedranyl anion, tris(trimethylsilyl)tetrahedranyllithium (3), has been synthesized by the reaction of tetrakis(trimethylsilyl)tetrahedrane (2) with methyllithium in tetrahydrofuran. The structural characterization of the tetrahedranyllithium has been achieved by X-ray crystallography, showing that the structure of 3.(TMEDA)1.5 represents a stretched tetrahedron. The endocyclic C(Li)-C(SiMe3) bond lengths range from 1.5408(15) to 1.5441(15) A (av 1.5425(15) A), and are longer than the endocyclic C(SiMe3)-C(SiMe3) bond lengths, which range from 1.4961(15) to 1.5009(15) A (av 1.4986(15) A). Methyl- and hydrogen-substituted tetrahedranes have also been prepared by the reaction of 3 with dimethyl sulfate and cyclopentadiene, respectively.     

Rare-Earth-compound nanowires, nanotubes, and fullerene-like nanoparticles: synthesis, characterization, and properties

Various low-dimensional nanostructures, such as nanowires, nanotubes, nanosheets, and fullerene-like nanoparticles have been selectively synthesized from rare-earth compounds (hydroxides, fluorides) based on a facile hydrothermal method. The subsequent dehydration, sulfidation, and fluoridation processes lead to the formation of rare-earth oxide, oxysulfide, and oxyhalide nanostructures, which can be functionalized further by doping with other rare-earth ions or by coating with metal nanoparticles. Owing to the interesting combination of novel nanostructures and functional compounds, these nanostructures can be expected to bring new opportunities in the vast research areas of and application in biology, catalysts, and optoelectronic devices.     

Diamond Nanowires: Fabrication,Structure, Properties,and Applications

C(sp³)? C‐bonded diamond nanowires are wide band gap semiconductors that exhibit a combination of superior properties such as negative electron affinity, chemical inertness, high Young’s modulus, the highest hardness, and room‐temperature thermal conductivity. The creation of 1D diamond nanowires with their giant surface‐to‐volume ratio enhancements makes it possible to control and enhance the fundamental properties of diamond. Although theoretical comparisons with carbon nanotubes have shown that diamond nanowires are energetically and mechanically viable structures, reproducibly synthesizing the crystalline diamond nanowires has remained challenging. We present a comprehensive, up‐to‐date review of diamond nanowires, including a discussion of their synthesis along with their structures, properties, and applications.     

Nitrosation, thiols, and hemoglobin: energetics and kinetics

Nitrosothiols are powerful vasodilators. Although the mechanism of their formation near neutral pH is an area of intense research, neither the energetics nor the kinetics of this reaction or of subsequent reactions have been addressed. The following considerations may help to guide experiments. (1) The standard Gibbs energy for the homolysis reaction RSNO → RS(?) + NO(?)(aq) is +110 ± 5 kJ mol(-1). (2) The electrode potential of the RSNO, H(+)/RSH, NO(?)(aq) couple is -0.20 ± 0.06 V at pH 7. (3) Thiol nitrosation by NO(2)(-) is favorable by 37 ± 5 kJ mol(-1) at pH 7. (4) N(2)O(3) is not involved in in vivo nitrosation mechanisms for thermodynamic--its formation from NO(2)(-) costs 59 kJ mol(-1)--or kinetic--the reaction being second-order in NO(2)(-)--reasons. (5) Hemoglobin (Hb) cannot catalyze formation of N(2)O(3), be it via the intermediacy of the reaction of Hb[FeNO(2)](2+) with NO(?) (+81 kJ mol(-1)) or reaction of Hb[FeNO](3+) with NO(2)(-) (+88 kJ mol(-1)). (6) Energetically and kinetically viable are nitrosations that involve HNO(2) or NO(?) in the presence of an electron acceptor with an electrode potential higher than -0.20 V. These considerations are derived from existing thermochemical and kinetics data.     

Polysulfide Polymers: Synthesis,Blending, Nanocomposites,and Applications

Abstract

Polysulfide polymers as an important class of polymers are used in different applications as sealants, adhesives, etc. They are usually synthesized by reaction of disodium polysulfides with dihalo compounds to yield liquid or solid polymers. Their most important advantages are excellent adhesion to different surfaces, creation of no defect in sealant under stress and pressure, resistance against to fuels and solvents, very low gas and steam permeability, and high resistance to ozone and UV. This article aims to review methods of synthesis, properties, and applications of polysulfide polymers. Also, polysulfide-based nanocomposites and blends are also briefly discussed.     

Magnetic nanoparticles: synthesis, protection, functionalization, and application

This review focuses on the synthesis, protection, functionalization, and application of magnetic nanoparticles, as well as the magnetic properties of nanostructured systems. Substantial progress in the size and shape control of magnetic nanoparticles has been made by developing methods such as co-precipitation, thermal decomposition and/or reduction, micelle synthesis, and hydrothermal synthesis. A major challenge still is protection against corrosion, and therefore suitable protection strategies will be emphasized, for example, surfactant/polymer coating, silica coating and carbon coating of magnetic nanoparticles or embedding them in a matrix/support. Properly protected magnetic nanoparticles can be used as building blocks for the fabrication of various functional systems, and their application in catalysis and biotechnology will be briefly reviewed. Finally, some future trends and perspectives in these research areas will be outlined.