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A critical overview of the latest developments in the aluminum battery technologies is reported. The substitution of lithium with alternative metal anodes characterized by lower cost and higher abundance is nowadays one of the most widely explored paths to reduce the cost of electrochemical storage systems and enable long-term sustainability. Aluminum based secondary batteries could be a viable alternative to the present Li-ion technology because of their high volumetric capacity (8040 mAh cm(-3) for Al vs 2046 mAh cm(-3) for Li). Additionally, the low cost aluminum makes these batteries appealing for large-scale electrical energy storage. Here, we describe the evolution of the various aluminum systems, starting from those based on aqueous electrolytes to, in more details, those based on non-aqueous electrolytes. Particular attention has been dedicated to the latest development of electrolytic media characterized by low reactivity towards other cell components. The attention is then focused on electrode materials enabling the reversible aluminum intercalation-deintercalation process. Finally, we touch on the topic of high-capacity aluminum-sulfur batteries, attempting to forecast their chances to reach the status of practical energy storage systems.

Thermal condensation of 2,3-diamino-1,4-(bistriisopropylsilylethynyl)benzene, -naphthalene,-anthracene, and -benzothiadiazole substrates with 1,2-naphthalenedione forms bent benzophenazine-type heteroarenes in a one-step reaction in good to excellent yields. The targets are investigated by UV/Vis spectroscopy, cyclic voltammetry, and single-crystal X-ray crystallography. The packing of the targets in the solid state follows either a herringbone or a brick wall motif. In the case of 8,13-bis(triisopropylsilylethynyl)dibenzo[a,i]phenazine, polymorphs with either packing result.

Microwave (MW) irradiation facilitated synthesis provides fast, safe, simple, and green reaction conditions. MW irradiation of 2-aminobenzophenones with heteroaromatic ketones afforded quinolines via Friedlander condensation in high yields with intact halogen substituents for further modifications. Dibenzo[b,f][1,5]diazocines were found as minor products and in some instances as the only products as the result of self-condensation of 2-aminobenzophenones. Different acid catalysts were found to affect these cyclization processes. Mini library of quinolines and dibenzo[b,f][1,5]diazocines were created in order to understand the substituents effect on the reaction. Resultant quinolines and dibenzo[b,f][1,5]diazocines are anticipated to serve as an interesting library for high throughput screening of various biological applications.

Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m−3 over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m−3 is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps.

The review describes methods for the preparation of complexes bearing protic NHC ligands, i.e. NHCs featuring an NH,NH or NH,NR substitution pattern. The protic NHC ligands are easily functionalized at the ring nitrogen atoms after N–H deprotonation. Thus the introduction of various functional groups at the ring nitrogen atoms is possible giving access to new complexes with NHC ligands and even allowing the linkage of individual protic NHCs to give macrocyclic ligands with NHC donors. Selected applications for complexes bearing protic NHCs will be described.

Next to complexes bearing N,N′-dialkylazolium-derived N-heterocyclic carbenes (NR,NR-NHCs), the coordination chemistry of protic NHC ligands (NH,NR-NHCs and NH,NH-NHCs) has recently attracted atten...

The products are obtained as single diastereomers with moderate to high enantiomeric excess.

Nature employs a variety of tactics to precisely time and execute the processes and mechanics of life, relying on sequential sense and response cascades to transduce signaling events over multiple length and time scales. Many of these tactics, such as the activation of a zymogen, involve the direct manipulation of a material by a stimulus. Similarly, effective therapeutics and diagnostics require the selective and efficient homing of material to specific tissues and biomolecular targets with appropriate temporal resolution. These systems must also avoid undesirable or toxic side effects and evade unwanted removal by endogenous clearing mechanisms. Nanoscale delivery vehicles have been developed to package materials with the hope of delivering them to select locations with rates of accumulation and clearance governed by an interplay between the carrier and its cargo. Many modern approaches to drug delivery have taken inspiration from natural activatable materials like zymogens, membrane proteins, and metabolites, whereby stimuli initiate transformations that are required for cargo release, prodrug activation, or selective transport. This Perspective describes key advances in the field of stimuli-responsive nanomaterials while highlighting some of the many challenges faced and opportunities for development. Major hurdles include the increasing need for powerful new tools and strategies for characterizing the dynamics, morphology, and behavior of advanced delivery systems in situ and the perennial problem of identifying truly specific and useful physical or molecular biomarkers that allow a material to autonomously distinguish diseased from normal tissue.

The synthesis of a new class of spiro-β-lactams (VIII) having an 8-azabicyclo[3.2.1]octan-3-one ring is described using the Staudinger reaction as key step.

A squaramide-catalyzed asymmetric multicomponent Michael/aza-Henry/cyclization triple domino reaction of 1,3-dicarbonyl compounds, β-nitroolefins, and imines to provide potentially bioactive tetrahydropyridines in good yields and excellent enantioselectivities is developed.

Bi1-xBaxFeO3-x/2 (x = 0.2, 0.3) phases are synthesized by solid state reaction of stoichiometric mixtures of BaCO3, Bi2O3, and Fe2O3 (850—920 °C, 30—45 h, yield given in g).

One monocyclofarnesol-derived sesquiterpenoid (1), four new meroterpenoids (2–5) as well as two isolation artifacts (6–7) and a known sesquiterpenoid (8) were isolated from the marine sponge Ircinia sp. Their chemical structures were elucidated via analyses of spectroscopic data, which included NMR and HRMS data. Two terpenoids, 1 and 4, showed PPARδ agonistic activities, with EC50 values of 18 and 30 μg/mL, respectively.

A diastereo- and enantioselective Michael/Henry/ketalization sequence to functionalized tetrahydropyrans is described. The multicomponent cascade reaction uses acetylacetone or β-keto esters, β-nitrostyrenes, and alkynyl aldehydes as substrates affording tetrahydropyrans with five contiguous stereocenters. Employing a bifunctional quinine-based squaramide organocatalyst, the title compounds are obtained in moderate to good yields (27–80%), excellent enantiomeric excesses (93–99% ee), and high diastereomeric ratios (dr > 20:1) after one crystallization.

Nondestructive intercalation and de-intercalation of mobile Li ions in γ-Fe2O3 results in a significant reversible change of the magnetic state of the material.

Summary It is the aim of this review to discuss the preparation, the atomic structure and the properties of nanometer structured solids that consist either totally or partially of amorphous components. We shall try to present evidence suggesting that it is the variation of the boundary conditions applied for preparing these nano-structures that open the way to a variety of materials with new atomic arrangements/new properties ranging from nano-glasses to switchable atomic quantum transistors. In order to discuss the basic ideas, we shall consider (in the first part of this review) solid materials that are assembled of nanometer-sized crystalline or amorphous building blocks connected by interfaces. The resulting materials are called nano-crystalline materials (nc) and nano-glasses (NG). Nano-crystalline materials and nano-glasses are solid materials composed of nanometer-sized crystalline or nanometer-sized glassy regions connected by crystal/crystal or glass/glass interfaces. As the atomic structures of these interfaces differ from the ones in the building blocks, the atomic and electronic structures of these interfaces differ from the ones in the building blocks. The atomic and the electronic structures (and hence the properties) of nano-crystalline materials and/or nano-glasses differ from the ones of single crystals or of glasses, respectively, that are available today with the same chemical compositions. In the second part of this review solid materials will be discussed the properties of which are controlled by nanometer spaced solid/liquid or solid/gas interfaces. The first group of materials of this kind to be discussed are nano-porous metals with electrolyte or gas filled interconnected nanometer-sized ligaments. The properties of the resulting numerous solid/liquid or solid/gas interfaces may be controlled reversibly by external variables e.g. by applying an external voltage between an aqueous electrolyte in the pores and the nano-porous metal or by varying the chemical composition of the gas in the pores. Due to the high density (∼1015 mm−3) of nano-scale ligaments, the entire nano-porous material reacts and becomes a solid of macroscopic dimensions with tunable mechanical, electric, magnetic, etc. properties. The other group of materials to be discussed in the second section of this review are nanometer-sized single crystals embedded in an aqueous electrolyte. By varying the boundary conditions for the formation of these nanometer-sized crystals, the size, the shape and the electronic structure of these nanometer-sized crystals can be switched reversibly so that switchable quantum transistors are obtained. All of these findings may also be interpreted in a more general context suggesting that in all the above mentioned cases, complex structures evolve if the following four conditions are met: (i) a substrate or nucleation site, on which the structures can organize, (ii) a free volume providing the sterical degrees of freedom for building the new structures, (iii) a reservoir of building blocks (molecules, atoms, ions, crystallites, glassy clusters) from which the structures can be (reversibly or irreversibly) formed and finally (iv) confined geometries preventing the return to thermal equilibrium by preventing the growth of macroscopic single crystals. This general approach seems to open the way for understanding and developing the guidelines for the growth of new self-organized complex material systems far from thermal equilibrium.

This minireview reports the most recent advances in the use of heterometallic catalysts based on single-frame N-heterocyclic carbene ligands. The article describes the synthetic strategies for the preparation of heterometallic catalysts, and their applications in the design of tandem processes by combining the catalytic properties associated with the two (or more) different metal centers. Several examples are discussed in which the use of heterometallic complexes results in a clear enhancement of the catalytic outcome compared to the results provided by mixtures of related homometallic complexes. The field constitutes a research area that is full of potential and is at its very earliest stage.

An organocatalytic nitroalkane-Michael/Henry reaction sequence to functionalized 1,2,3,4-tetrahydronaphthalen-1-ols is described. Starting from 2-(nitromethyl)benzaldehyde and nitroalkenes a bifunctional quinine-based squaramide organocatalyst is used to afford the title compounds in moderate to very good yields (25–84%), high diastereomeric ratios (dr>95:5) after crystallization and good to excellent enantioselectivities of 63–99% ee. Starting from γ-nitro aldehydes and ketones secondary and tertiary cyclohexanols bearing four stereogenic centers can also be prepared with this Michael/Henry domino reaction.

The title compound is prepared from the elements in a CsCl flux (silica tube, 923 K, 5 d) and characterized by single crystal XRD.

Complexes bearing “protic” N-heterocyclic carbene (NHC) ligands (NR,NH-NHCs) have been shown to use the NH group of the NHC ligand for the formation of hydrogen bonds to selected substrates. This type of hydrogen bond can be used for substrate recognition, selection, and orientation. In contrast to related systems, the hydrogen bond donor and thus the molecular recognition unit is located in proximity to the metal center. This concept article discusses major strategies for the preparation of complexes bearing protic NHC ligands and their potential applications.

Unique and fascinating features of metal oxide nanostructures (MONs) have attracted considerable attention in recent years because without much effort, the MONs can be grown in many different nanoscale forms, thus allowing various novel devices of chemical and biological sensing to be fabricated. To improve the sensors performance by tailoring the properties of MONs through engineering of morphology, particle size, effective surface area, functionality, adsorption capability and electron-transfer properties have been extensively explored. This feature article collates the various MONs and their potential applications in the chemical and biological sensors for clinical and non-clinical applications.

The sequence is highly diastereo- and enantioselective and produces different tricyclic heterocyclic scaffold as base structures of natural products.

Poly-NHC (NHC = N-heterocyclic carbene) ligands emerged almost immediately after the first stable NHCs had been described. Macrocyclic ligands, featuring NHC donor groups and their metal complexes, however, remained rare until recently. This perspective highlights modern developments in the fields of synthesis and coordination chemistry of macrocyclic poly-NHC ligands. These include the synthesis of tetracarbene ligands which were obtained from complexes of β-functionalized isocyanides followed by cyclization of the coordinated iscocyanide ligands to NH,NH-functionalized NHCs and the subsequent metal template controlled bridging alkylation of the NH,NH-NHCs to yield the macrocycle. The template synthesis of ligands featuring a mixed NHC/phosphine donor set like [11]ane-P2CNHC and [16]ane-P2CNHC2 by linkage of NH,NH-NHCs to different phosphines is also presented. Finally, methods for the preparation of cyclic polyazolium salts, their deprotonation and metalation and the different modes of coordination of such macrocyclic poly-NHC ligands are discussed.

Enzymes are the prime protagonists in the chemistry of living organisms. As such, chemists and biologists have long been fascinated by the array of highly selective transformations possible under biological conditions that are facilitated by enzyme-catalyzed reactions. Moreover, enzymes are involved in replicating, repairing and transmitting information in a highly selective and organized fashion through detection and signal amplification cascades. Indeed, because of their selectivity and potential for use outside of biological systems, enzymes have found immense utility in various biochemical assays and are increasingly finding applications in the preparation of small molecules. By contrast, the use of enzymatic reactions to prepare and build supramolecular and nanoscale materials is relatively rare. In this article, we seek to highlight efforts over the past 10 years at taking advantage of enzymatic reactions to assemble and manipulate complex soft, organic materials on the nanoscale. It is tantalizing to think of these processes as mimics of natural systems where enzymes are used in the assembly and transformation of the most complex nanomaterials known, for example, virus capsid assemblies and the myriad array of nanoscale biomolecular machinery.

A facile method for the preparation of N1- (1a–6a) and N3-alkylated (1b–6b) 4-azabenzimidazole derivatives is presented. Both isomers were obtained by alkylation of 4-azabenzimidazole. The isomers were separated, and the preferred formation of the N1-alkylated derivatives (1a–6a) was observed. The C2-proton in the alkylated benzimidazoles can be exchanged for an iodine atom by treatment with methyl lithium and iodine, leading to N-alkylated 2-iodo-4-azabenzimidazoles 7a,b and 8a. 2,2′-Bis(4-azabenzimidazole) derivatives 9a,b and 10a were isolated as by-products of the proton–halogen exchange. Treatment of the N1- or N3-methyl-4-azabenzimidazoles 1a,b with methyl lithium and N-chlorosuccinimide as a chlorine source proceeded to give 2-chloro-4-azabenzimidazoles 11a,b without formation of the coupling products, but the yield of 2-chloro-1-methyl-4-azabenzimidazole 11a is low (9%) whereas 2-chloro-3-methyl-4-azabenzimidazole 11b has been obtained in reasonable yield (49%). The reaction of 3-butyl-2-iodo-4-azabenzimidazole 7b with [IrCl2Cp*]2 gave the iridium complex 12, where 3-butyl-2-iodo-4-azabenzimidazole is coordinating to the metal center via the N1 atom. The reaction of the N1-alkylated 4-azabenzimidazole with chloroacetone gave the corresponding 1-alkyl-3-(2-oxopropyl)-4-azabenzimidazolium chlorides 13–17 in good yields. The chloride counterion was exchanged for a tetrafluoroborate anion for two derivatives leading to compounds 18 and 19. Carbene complexes were obtained by treatment of 1-butyl-3-(2-oxopropyl)-4-azabenzimidazolium chloride 15 with silver oxide, followed by transmetalation with [AuCl(tht)] or [IrCl2Cp*]2 leading to the gold(I) (20) and iridium(III) complexes (21) with 1-butyl-3-(2-oxopropyl)-4-azabenzimidazolin-2-ylidene ligand. Removal of the 2-oxopropyl protecting group by treatment with silica gel proceeded in the case of the iridium complex to give complex 22, possessing an NH,NR-stabilized carbene ligand, while it failed for the gold(I) complex. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:476–490, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20711

The title solid solutions (0 ≤ x ≤ 1) are prepared by milling stoichiometric mixtures of Bi2O3, Ga2O3, and α-Al2O3 in air (3 h, 600 rpm) followed by annealing at 800 °C in air for 24 h.

The reaction of symmetric disulfides (I) with sulfuryl chloride gives sulfenyl chlorides, which are directly coupled with thiols (II) in the presence of water to yield unsymmetrical disulfides (III).

This overview focuses on the design and preparation of phthalocyanines (Pcs) and covers both fundamental synthetic approaches and more applied research. Thus, different topics including, e.g., the preparation of conjugated assemblies using Pcs as synthetic building blocks, the supramolecular organization of appropriately featured Pc-molecules, and the incorporation of Pcs into dendrimers and polymers, are discussed in this chapter. The second part of the review has been devoted to more technological aspects of these compounds covering Pc-based nanostructures and Pcs as active components of functional devices.

N-Heterocyclic carbenes (NHCs) have developed into an important class of ligands in transition metal coordination chemistry. They have been employed successfully as spectator ligands in various catalytically active metal complexes and as organocatalysts. In this chapter we present some important synthetic methods for the preparation of various NHCs and their metal complexes.

2-Iminothiazole, an isoform of 2-aminothiazole, is a scaffold of synthetic and medicinal significance. We have reported an efficient method by which alkyl group of 2-alkyliminothiazoles is changed into other alkyl groups by isothiocyanates. In this article, a detailed mechanistic aspect, and the scopes and limitations were disclosed. All the reactions were carried out in toluene at 105 °C without any additive. The reaction is a reversible process and the equilibrium is determined by the reactivity of both reactants, in which the more electron-withdrawing alkyl or aryl groups at the 2-imino group or isothiocyanate showed higher reactivities. With this simple method, we effectively altered the alkyl group attached on the imine nitrogen. A synthetic problem in 2-iminothiazole chemistry, synthesis of amino acid-derived 2-iminothiazole was solved in a very simple manner. Using suitably designed 2-iminothiazole substrate, the electrophilic reactivity of various isothiocyanates could be empirically compared by this exchange reaction. Moreover, successful exchange reaction using isocyanates instead of isothiocyanates broadened the utility of this reaction.

The laccase-catalyzed cyclization of dihydroxybenzoic acid derivatives (I) with amino-carboxamides leads to a variety of fused diazepines in low to moderate yields.

A new synthesis of chromones and flavones based on the ortho-directed metalation of methoxymethyl aryl ethers with alkyllithium reagents is described. It entails reaction of the ortho-lithiated intermediates with a conjugated unsaturated aldehyde followed by oxidation of the allylic alcohol product with «periodinane» to yield an ortho-allylic ketone. The latter on heating in acetic acid undergoes loss of the methoxymethyl protecting group and cyclization to a chromanone (or flavanone, if a β-phenyl substituent is present). Dehydrogenation by treatment with pyrrolidone hydrotribromide (PHT) in dimethyl sulfoxide yields the corresponding chromones (or flavones). This synthetic approach appears general in its applicability