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Some rodlike organic molecules exhibit exceptionally high layered crystallinity when composed of a link between π‐conjugated backbone (head) and alkyl chain (tail). These molecules are aligned side‐by‐side unidirectionally to form self‐organized polar monomolecular layers, providing promising 2D materials and devices. However, their interlayer stacking arrangements have never been tunable, preventing the unidirectional arrangements of molecules in whole crystals. Here, it is demonstrated that polar/antipolar interlayer stacking can be systematically controlled by the alkyl carbon number n, when the molecules are designed to involve effectively weakened head‐to‐head affinity. They exhibit remarkable odd–even effect in the interlayer stacking: alternating head‐to‐head and tail‐to‐tail (antipolar) arrangement in odd‐n crystals, and uniform head‐to‐tail (polar) arrangement in even‐n crystals. The films show excellent field‐effect transistor characteristics presenting unique polar/antipolar dependence and considerably improved subthreshold swing in the polar films. Additionally, the polar films present enhanced second‐order nonlinear optical response along normal to the film plane. These findings are key for creating polarity‐controlled optoelectronic materials and devices. [ABSTRACT FROM AUTHOR]

The elucidation of the factors determining liquid structures and transport properties of ionic liquids is important for the design and development of ionic liquid electrolytes. This personal account introduces the importance of computational methods for studying ionic liquids. Molecular dynamics simulations provide detailed information on liquid structures of ionic liquid such as the structures of solvated cation complexes in equimolar mixtures of glymes and Li[TFSA] and the effects of the charges of electrode on liquid structure near the electrode. Ab initio calculations reveal that the magnitude of the attraction between ions and conformational flexibility ions play important roles in determining transport properties of ionic liquids. First principle molecular dynamics simulations elucidate why solvated cation complex is stable in the equimolar mixtures, although the Li+‐[TFSA]− interaction is greater than Li+‐glyme interaction. [ABSTRACT FROM AUTHOR]

The performance of 24 vdW‐DF functionals were evaluated. The calculated intermolecular interaction potentials for 11 complexes, which conatain O, S, Se, N, P, F, Cl and Br atoms, were compared with CCSD(T)/CBS level potentials to evaluate their accuracy. The performance depends on the choice of vdW‐functional significantly. The vdW‐DF3‐opt1 functional shows the best performance. The deviation ratios of calculated interaction energies of the complexes using the vdW‐DF3‐opt1 functional to CCSD(T) level interaction energies at the potential minima are −6 to 14 %. As a general tendency, the accuracy is improved in the order of vdW‐DF, vdW‐DF2, and vdW‐DF3, but even if they belong to the same group, the accuracy greatly differs depending on each functional. The calculations of hydrocarbon molecules show better performance compared with heteroatom containing molecules in most cases. The calculations using the vdW‐DF3‐opt1 functional and the best dispersion corrected DFT calculations show nearly identical performance. [ABSTRACT FROM AUTHOR]

Solvate ionic liquids (SILs) composed of glymes and Li salts are potential electrolyte materials for Li ion batteries. Safety and durability of SIL‐based batteries can be realized by competing characters of solvate cations. Solvate structure of Li+ should be stable in the bulk to be nonvolatile, and its desolvation should occur rapidly on electrode surfaces which is considered as a rate‐limiting step in charging or discharging. To investigate such characters, potential‐dependent interfacial structure of [Li(G4)][TFSA], equimolar mixture of tetraglyme and lithium bis(trifluoromethanesulfonyl)amide, on an Au electrode has been investigated at the molecular scale by using surface‐enhanced infrared absorption spectroscopy. Despite discrete solvate ion [Li(G4)]+ is stable in the bulk, partial desolvation of Li+ on the electrode was observed at around the potential of zero charge, much more positive than Li+ reduction reactions. The driving force of the partial desolvation can be ascribed to the breaking of isotropic dielectric environment in the vicinity of the electrode, where image charge induced on the electrode surface stabilizes the partially desolvated structure enabling shorter Li+‐electrode distance. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations of ionic liquids composed of N‐propyl‐N‐methylpyrrolidinium cation ([pmpyro]+) with (CF3SO2)2N− ([TFSA]−), (FSO2)2N− ([FSA]−), CF3SO3−, CF3CO2− and PF6− anions sandwiched by two charged graphene sheets show that the liquid structures near graphene sheets depend strongly on anion. Long‐range charge ordering structures were observed when the ionic liquids were sandwiched with charged graphene sheets. Although the magnitude of the oscillation of cation and anion densities near charged graphene sheets is enhanced by the increase of the charges on the graphene sheets, the range of the charge‐ordering structures from the graphene sheets does not largely change. The ranges of the charge‐ordering structures from charged graphene sheets observed in the [pmpyro][TFSA], [pmpyro][FSA], [pmpyro][CF3SO3], [pmpyro][CF3CO2] and [pmpyro][PF6] ionic liquids are approximately 40, 80, 60, 60 and 100 Å, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Using a halogen bond (XB) donor and Schreiner's thiourea as cooperative catalysts, various amides, including the asparagine residues of several peptides, were directly coupled with glycosyl trichloroacetimidates to give unique N‐acylorthoamides in good yields. Synthetic applications of N‐acylorthoamides, including rearrangement to the corresponding β‐N‐glycoside, were also demonstrated. [ABSTRACT FROM AUTHOR]

X-ray crystallographic analyses of a series of trifluoroethoxy-substituted subphthalocyanines disclosed that a molecule of toluene is clasped at the center of the molecular concave cavity. Twelve trifluoroethoxy substituents, which flexibly surround the toluene molecule to hold it on the 14π-electron-conjugated surface of the subphthalocyanines, can also catch a molecule of benzene. In contrast, a nonsubstituted subphthalocyanine does not show the same phenomena, and two subphthalocyanine units are required to maintain a small aromatic compound in their concave cavity. DFT calculations of the complexes were conducted to better understand the arene clathrates. Trifluoroethoxy-substituted subphthalocyanines can be used to prepare arene clathrates as a result of their concave space. This is a unique approach to obtaining X-ray crystal structures of small noncrystalline aromatic compounds. [ABSTRACT FROM AUTHOR]

The umpolung alkylation of silyl enol ethers with an iodonium(III) ylide proceeds under mild conditions to afford various 1,4-dicarbonyl compounds in high yields in the presence of a halogen-bonding catalyst. Unlike typical transition-metal activation processes of such ylide precursors, which tend to proceed via carbenoid intermediates, experimental and computational studies indicate that halogen bonding (XB) between the XB donor catalyst and the iodonium ylide plays a crucial role in promoting the reaction. The identification of a compatible Bronsted base catalyst enabled the extension of this method to enols generated in situ to give the corresponding adducts in good yields. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon materials (NDCs) play an important role in various fields. A great deal of effort has been devoted to obtaining carbon materials with a high nitrogen content; however, much is still unknown about the structure of the nitrogen-doped materials and the maximum nitrogen content possible for such compounds. Here, we demonstrate an interesting relationship between the N/C molar ratio and the N content of NDCs. The upper limit for the nitrogen content of NDCs that might be achieved was estimated and found to strongly depend on the carbonization temperature (14.32 wt % at 1000 °C and 21.66 wt % at 900 °C), irrespective of the precursor or preparation conditions. Simulations suggest that, especially in the carbon architectures obtained at high temperatures, nitrogen atoms are always located on separate hexagon moieties in a graphitic configuration, thereby yielding a critical N/C molar ratio very close to the value estimated from the experimental results. [ABSTRACT FROM AUTHOR]

The effect of silyl substituents in diphenylprolinol silyl ether catalysts was investigated. Mechanistically, reactions catalyzed by diphenylprolinol silyl ether can be categorized into three types: two that involve an iminium ion intermediate, such as for the Michael-type reaction (type A) and the cycloaddition reaction (type B), and one that proceeds via an enamine intermediate (type C). In the Michael-type reaction via iminium ions (type A), excellent enantioselectivity is realized when the catalyst with a bulky silyl moiety is employed, in which efficient shielding of a diastereotopic face of the iminium ion is directed by the bulky silyl moiety. In the cycloaddition reaction of iminium ions (type B) and reactions via enamines (type C), excellent enantioselectivity is obtained even when the silyl group is less bulky and, in this case, too much bulk reduces the reaction rate. In other cases, the yield increases when diphenylprolinol silyl ethers with bulky substituents are employed, presumably by suppressing side reactions between the nucleophilic catalyst and the reagent. The conformational behaviors of the iminium and enamine species have been determined by theoretical calculations. These data explain the effect of the bulkiness of the silyl substituent on the enantioselectivity and reactivity of the catalysts. [ABSTRACT FROM AUTHOR]

We describe the facile synthesis of 3-substituted indoles by Friedel-Crafts-type conjugate addition catalyzed by imidazolium salts. The reactions proceed under mild conditions with no base, solvent, or N-heterocyclic carbene. Mechanistic studies suggest the potential mechanism operates through the dual activation of indoles involving cation-π interactions of imidazolium cations with indoles and Lewis base activation by chloride anions derived from the imidazolium salts. High-level ab initio molecular orbital calculations reveal that there is a strong attraction between the imidazolium cation and the indole, and that the electrostatic and induction interactions strongly contributes to the attraction in the indole/imidazolium complex, which is a characteristic feature of the cation-π interaction. [ABSTRACT FROM AUTHOR]

Remarkably enhanced stability of the self-assembled hydrogen-bonded heterocapsule 1⋅2 by the encapsulation of 1,4-bis(1-propynyl)benzene 3 a was found with Ka=1.14×109 M−1 in CDCl3 and Ka2=1.59×108 M−2 in CD3OD/CDCl3 (10 % v/v) at 298 K. The formation of 3 a@( 1⋅2) was enthalpically driven (Δ H°<0 and Δ S°<0) and there was a unique inflection point in the correlation between Δ H° versus Δ S° as a function of polar solvent content. The ab initio calculations revealed that favorable guest-capsule dispersion and electrostatic interactions between the acetylenic parts (triple bonds) of 3 a and the aromatic inner space of 1⋅2, as well as less structural deformation of 1⋅2 upon encapsulation of 3 a, play important roles in the remarkable stability of 3 a@( 1⋅2). [ABSTRACT FROM AUTHOR]

Quinine, one of Cinchona alkaloids, has been of great interest from medical, synthetic, and supramolecular viewpoints. However, unaccountably, the guest-free (GF) crystal of quinine containing no solvent or other molecules has not been reported for nearly three decades, although GF crystals of other Cinchona alkaloids, such as quinidine, cinchonidine, and cinchonine, are already known. In this study, we successfully revealed the crystal structure of quinine, which belongs to the P21 space group with the cell parameters of a=6.0587(1), b=19.2492(5), c=22.2824(7) Å, β=92.1646(11)°, and V=2596.83(12) Å3. Interestingly, the crystal has three crystallographically independent molecules in the cell ( Z′=3) that are connected through a N(quinoline)⋅⋅⋅HO hydrogen bond to form a pseudo three-two-fold (32) double-helical motif. The helical motif is completely different from those observed in GF crystals of other Cinchona alkaloids. Hierarchical comparison on the crystal structures of a series of Cinchona alkaloids including quinine clearly demonstrated that only small structural differences of a molecule, particularly the position of the vinyl group, cause a significant variety of assembly manner in the crystalline state. There have been no reports systematically demonstrating such steric effect in crystals of Cinchona alkaloids, and, therefore, the present system contributes to the design of desired functional crystal structures. [ABSTRACT FROM AUTHOR]

We recently discovered a new gene, Desiccate ( Desi), that is expressed in the epidermis and protects larvae from desiccation stress in Drosophila melanogaster. In the present study, we found that taste organs express more Desi than the epidermis both in larvae and adults. Green fluorescent protein (GFP) expression in larvae under the direction of a Desi promoter- Gal4 line containing the 1,010-bp 5′ flanking region of Desi produced no signal in the epidermis but strong signals in cells of the larval gustatory sense organs, indicating that this driver works specifically in the gustatory organs. In adults, GFP expression was also observed in basal cells of sensilla on labella, tarsi and wings. More precise morphological analysis of GFP expression located its expression in the outer accessory cells rather than neurons of the labial sensilla. Although Desi knockdown or induction of cell death in Desi-expressing cells did not change the morphological or physiological characters of the larvae, larvae lacking Desi-expressing cells failed to metamorphose normally, and all of them died inside puparia. Dying pharate adults were found to lack all labial sensilla. The proneural genes Achaete and Scute, which are involved in the development of the adult central and peripheral nervous system, were normally expressed in the pupae lacking Desi-expressing cells. These results suggested that the lack of Desi-expressing cells makes it impossible to produce outer accessory cells for development of the sensilla, thereby signifying that cells expressing Desi are essential for normal morphogenesis of the labial sensilla in Drosophila adults. [ABSTRACT FROM AUTHOR]

Growth-blocking peptide (GBP) is a 25 amino acid insect cytokine found in lepidopteran insects that has diverse biological activities, such as larval growth regulation, paralysis induction, cell proliferation, and stimulation of immune cells. GBP also enhances expression of the tyrosine hydroxylase (TH, EC 1.14.16.2) and 3,4-dihydroxy-l-phenylalanine (Dopa) decarboxylase (DDC, EC 4.1.1.26) genes, which elevate dopamine levels in insect epidermal cells. We used insect epidermis and cultured cells to define the role of the GBP signaling pathway in the enhancement of TH and DDC gene expression. It has been recently reported that robust expression of the DDC gene requires activation of extracellular signal-regulated kinase (ERK) in epidermal cells of wounded Drosophila embryos. This study confirmed that GBP activates ERK, but this activation is not directly linked to the enhancement of TH and DDC gene expression. One of the GBP pathway components is phospholipase C, whose activation is essential for the activation of ERK and elevation of expression of both enzyme genes. The downstream signaling pathways diverge to ERK activation through activated protein kinase C and expression of the enzyme genes through inositol triphosphate receptor-mediated Ca2+ influx from extracellular fluid. Our data indicate that the diverged GBP signaling pathways enable GBP to exert completely different biological functions, even in a single cell type. [ABSTRACT FROM AUTHOR]

The development of new electrolytes for lithium–sulfur (Li–S) batteries is important. Electrolytes based on 1:1 glyme:Li+ complexes can be locally destroyed to form free glyme during charge/discharge cycles. Free glyme can cause Li2Sx dissolution, which is a major factor in Li–S battery degradation. To decrease the local generation of free glyme, the glyme:Li+ electrolytes with higher proportions of Li salts are developed to control the Li2Sx dissolution into the electrolyte. The chemical solubility of Li2S8 and the charge/discharge properties of Li–S cells are investigated by varying the glyme:Li salt molar ratio. Nonequimolar (high Li salt concentration) glyme:Li salt mixture electrolytes directly suppress the Li2S8 dissolution and improve the charge/discharge properties (cycling and coulombic efficiency) of Li–S cells. The electrolyte composition can control the chemical stability of reactive intermediates at the Li2Sx electrode and provide high‐performance Li–S cells for next‐generation batteries. [ABSTRACT FROM AUTHOR]

A base free imidazoline salt catalyzed Friedel-Crafts conjugate addition of indoles to α,β-unsaturated ketones and a related nitrostyrene is described. [ABSTRACT FROM AUTHOR]

Review: 151 refs. [ABSTRACT FROM AUTHOR]

The crystal structures of the four E, Z, E isomers of 1-(4-alk­oxy­phen­yl)-6-(4-nitro­phen­yl)hexa-1,3,5-triene, namely ( E, Z, E)-1-(4-methoxy­phen­yl)-6-(4-nitro­phen­yl)hexa-1,3,5-triene, C19H17NO3, ( E, Z, E)-1-(4-ethoxy­phen­yl)-6-(4-nitro­phen­yl)hexa-1,3,5-triene, C20H19NO3, ( E, Z, E)-1-(4-nitro­phen­yl)-6-(4- n-propoxyphen­yl)hexa-1,3,5-triene, C21H21NO3, and ( E, Z, E)-1-(4- n-butoxy­phen­yl)-6-(4-nitro­phen­yl)hexa-1,3,5-triene, C22H23NO3, have been determined. Inter­molecular N⋯O dipole inter­actions between the nitro groups are observed for the meth­oxy derivative, while for the eth­oxy derivative, two adjacent mol­ecules are linked at both ends through N⋯O dipole–dipole inter­actions between the N atom of the nitro group and the O atom of the eth­oxy group to form a supra­molecular ring-like structure. In the crystal structures of the n-prop­oxy and n-but­oxy derivatives, the shortest inter­molecular distances are those between the two O atoms of the alk­oxy groups. Thus, the nearest two mol­ecules form an S-shaped supra­molecular dimer in these crystal structures. [ABSTRACT FROM AUTHOR]