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Front cover: In establishing the left‐right axis of the body in Drosophila, a torsion‐like deformation of the cell occurs (cell chirality). Two myosin Is, Myo1D and Myo1C, are thought to be involved in this process, producing right‐handed and left‐handed cell chirality, respectively. A paper published in the May issue of this journal (Utsunomiya et al. (2024) Genes Cells 29: 380‐396, DOI: 10.1111/gtc.13110) reported that when these myosin Is were expressed in macrophages to observe their interactions with the membrane at the single‐molecule level, Myo1D exhibited mobility consistent with free diffusion, whereas Myo1C showed notably lower mobility. This picture, depicting two vortices in a strait, aptly illustrates their differences. Compared to the fast currents that produce the right‐handed vortex in the back, the currents of the left‐handed vortex in the foreground are docile. Designed by TRAIS Co., Ltd. (Kobe, Japan). [ABSTRACT FROM AUTHOR]

Chirality has become an important research subject. The research areas associated with chirality are under substantial development. Meanwhile, graphene is a rapidly growing star material and has hard‐wired into diverse disciplines. Rational combination of graphene and chirality undoubtedly creates unprecedented functional materials and may also lead to great findings. This hypothesis has been clearly justified by the sizable number of studies. Unfortunately, there has not been any previous review paper summarizing the scattered studies and advancements on this topic so far. This overview paper attempts to review the progress made in chiral materials developed from graphene and their derivatives, with the hope of providing a systemic knowledge about the construction of chiral graphenes and chiral applications thereof. Recently emerging directions, existing challenges, and future perspectives are also presented. It is hoped this paper will arouse more interest and promote further faster progress in these significant research areas. [ABSTRACT FROM AUTHOR]

Carbon‐based nanomaterials have catalyzed breakthroughs across various scientific and engineering disciplines. The key to unlocking a new generation of tailor‐made nanomaterials based on single‐walled carbon nanotubes (SWCNTs) lies in the precise sorting of raw material into individual chiralities, each possessing unique properties. This can be achieved using conjugated polymer extraction (CPE), but to a very limited extent since the process generates only a few chirality‐enriched suspensions. Therefore, it is imperative to comprehend the mechanism of the wrapping of SWCNTs by polymers to unleash CPE's full potential. However, the lack of a diverse palette of chirality‐selective polymers with varying macromolecular parameters has hindered a comprehensive understanding of how the nature of the polymer affects the performance and selectivity of SWCNT isolation. To address this gap, multiple batches of such polymers are synthesized to elucidate the impact of molecular weight and dispersity on the purity and concentrations of the generated SWCNT suspensions. The obtained results explain the inconsistent outcomes reported in the literature, greatly improving the application potential of this promising SWCNT sorting approach. Concomitantly, the discovered significant influence of the macromolecular characteristics of conjugated polymers on the SWCNT isolation efficacy sheds considerable insight into the unresolved mechanism of this sorting technique. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are of interest in various industries owing to their high aspect ratio, electrical conductivity, and other properties. By maximizing the number of CNTs in their solvents or matrices, the electrical and mechanical performance in applications such as batteries, sensors, and transistors can be enhanced. However, the hydrophobicity of CNTs' surface induces aggregation that adversely impacts their performance. To overcome this obstacle, many researchers have been designing novel dispersants with performances exceeding that of existing commercial dispersants. This article reviews contemporary studies on CNT dispersants from 2015 to 2022, along with the comprehensive features of CNTs depending on their chirality, number of walls, synthesis methods, and functionalization. Studies of CNT dispersants are primarily organized according to whether aqueous or organic solvents are used. This review article provides a clear perspective of CNT dispersants development today and how to design new CNT dispersants depending on the solvents. A conclusion is given to identify major challenges to the implementation of CNT dispersion and an outlook on future avenues of research. [ABSTRACT FROM AUTHOR]

Controlling chromophore chirality in three‐dimensional space is crucial for understanding the structure–chiroptical relationship. Such control enables the prediction of ideal materials for use in chiral photonic applications. In this study, optically active multipyrene systems are synthesized on peptoids. Pyrene‐based chiral submonomers, (S)‐ and (R)‐1‐pyrenylethylamine (s1pye and r1pye), are successfully incorporated into peptoids as the respective (S)‐ and (R)‐N‐(1‐pyrenylethyl)glycine (Ns1pye and Nr1pye) units. NMR spectroscopy revealed length‐ and N‐acetylation‐dependent conformational homogeneity enhancement in solution, stabilizing cis‐amides in Ns1pye‐containing peptoids. The X‐ray crystal structure of Ns1pye tetramer displayed a polyproline type‐I (PPI)‐like helix. All of the pyrene‐related absorptions are circular dichroism (CD) active, and the CD signal related to the long‐axis‐polarized transition increased with helical stabilization. Intramolecular excimer generation yielded significant circularly polarized luminescence (CPL) in the excimer emission region. Early‐stage peptoids emitted left‐handed CPL, but upon acquiring a PPI‐like helix character, CPL handedness became inverted. The CPL dissymmetry factor (glum) was comparable or superior (10−2) to that of chiral organic dyes (10−5–10−2). This new class of helical pyrene‐containing peptoids provides a CPL‐active intramolecular excimer, modulating optical activity through peptoid secondary structure homogeneity. [ABSTRACT FROM AUTHOR]

A family of transition metal complexes of meso‐aryl‐2‐aza‐21‐carbaporphyrin (N‐confused porphyrin, NCP) derivatives acting as ortho‐metallating ligands for ruthenium(II), rhodium(III), and iridium(III) is synthesized and characterized by XRD, spectroscopic, and electrochemical methods. The chirality of these systems is shown by the separation of the enantiomers and analyzed by circular dichroism and DFT. A preliminary catalytic study indicates the activity of the iridium(III) ortho‐metallated complexes in the N‐heterocyclization of primary amines with diols. [ABSTRACT FROM AUTHOR]

Chiral molecules are known to behave as spin filters due to the chiral induced spin selectivity (CISS) effect. Chirality can be implemented in molecular semiconductors in order to study the role of the CISS effect in charge transport and to find new materials for spintronic applications. In this study, the design and synthesis of a new class of enantiopure chiral organic semiconductors based on the well‐known dinaphtho[2,3‐b:2,3‐f]thieno[3,2‐b]thiophene (DNTT) core functionalized with chiral alkyl side chains is presented. When introduced in an organic field‐effect transistor (OFET) with magnetic contacts, the two enantiomers, (R)‐DNTT and (S)‐DNTT, show an opposite behavior with respect to the relative direction of the magnetization of the contacts, oriented by an external magnetic field. Each enantiomer displays an unexpectedly high magnetoresistance over one preferred orientation of the spin current injected from the magnetic contacts. The result is the first reported OFET in which the current can be switched on and off upon inversion of the direction of the applied external magnetic field. This work contributes to the general understanding of the CISS effect and opens new avenues for the introduction of organic materials in spintronic devices. [ABSTRACT FROM AUTHOR]

To develop a simple and general method for improving the circularly polarized luminescence (CPL) performances of materials is of great significance. In this work, two pairs of CPL‐active homochiral metal–organic frameworks (MOFs) P/M‐Et and P/M‐Et(Cd) with eta topology are reported. In comparison to the reported isomorphic Zn‐imidazolate MOFs P‐Me and M‐Me, both luminescence dissymmetry factor (glum) and photoluminescence quantum yields (ΦPL) of P‐Et and M‐Et are largely improved by simply changing the methyl group to an ethyl group of ligands in P‐Et and M‐Et. Furthermore, the |glum| values are significantly amplified up to 0.015 from 0.0057 by introducing the non‐luminescent halogenated aromatics, while an enhanced fluorescence efficiency is observed simultaneously (from 27.2% to 47.3%). The figure of merit value is about 40 times larger than that of P‐Me and M‐Me. Similarly, the CPL performances of P/M‐Et(Cd) are improved by about five times after encapsulating fluorobenzene molecules. This work represents a new and simple method for developing CPL‐active MOF materials. [ABSTRACT FROM AUTHOR]

Broadband terahertz (THz) chirality and wavefront manipulation play important roles in wireless communication, imaging, and radar systems. In this work, by integrating liquid crystal (LC) into a dielectric metasurface, the gradient phase distribution from the Si metasurface and the tunable birefringent phase shift from LC are engineered to perform an active spin‐decoupled beam steering with the strong spin asymmetric transmission. By using geometric symmetry analysis, the relationships between the symmetry breaking and the optical chirality of the metadevice are revealed under different LC orientations, and both the simulations and experiments further verify the dependence of this chirality on spin‐decoupled beam steering with different spin states. The results show that with the orientation changes of the LC by driving the different magnetic fields, the circular dichroism of the device at the 0° deflection angle is ≈100% dynamically modulated and even flipped in the broadband range of 0.8–1.3 THz. With these changes in THz chirality, a tunable spin‐decoupled beam steering occurs in the range of 25°‐45°. This work shows that tunable LC anisotropy leads to more complex symmetry breaking in this structure, and results in more functions than conventional spin‐decoupled wavefront manipulations, which expands the scope of THz chiral metadevice and its applications. [ABSTRACT FROM AUTHOR]

In this work, the gyrotropic semiconductor InSb into the twisted bilayer metasurface to form a magneto‐optical moiré metasurface is introduced. Through the theoretical analysis, the "moiré angle" is developed in which case the nonreciprocity and chirality with the spin‐conjugate asymmetric transmission are obtained due to the simultaneous breaking of both time‐reversal symmetry and spatial mirror symmetry. The experiments confirm that the chirality can be actively manipulated by rotating the twisted angle and the external magnetic field, realizing spin‐conjugate asymmetric transmission. Meanwhile, the two spin states also realize the nonreciprocal one‐way transmission, and their isolation spectra are also spin‐conjugate asymmetric: one is enhanced up to 48 dB, and the other's bandwidth is widened to over 730 GHz. This spin‐conjugate symmetry‐breaking effect in the MOMM brings a combination of time‐space asymmetric transmission, and it also provides a new scheme for the implementation of high‐performance THz chirality controllers and isolators. [ABSTRACT FROM AUTHOR]

Abrupt aggregation of misfolded proteins is a hallmark of many medical pathologies including diabetes type 2, Alzheimer and Parkinson diseases. This results in the formation of amyloid fibrils, protein aggregates with distinct supramolecular chirality. A growing body of evidence suggests that lipids can alter rates of protein aggregation. In this study, we investigated whether lipids could alter the supramolecular chirality of amyloid fibrils. We found that if present at the stage of protein aggregation, phospho‐ and sphingolipids uniquely reversed supramolecular chirality of insulin and lysozyme fibrils. Furthermore, amyloid fibrils with opposite supramolecular chirality exerted distinctly different cell toxicity. Specifically, insulin and lysozyme fibrils with reversed supramolecular chirality were less toxic to cells than the aggregates with normal supramolecular chirality. These findings point on the important role of lipids and supramolecular chirality of amyloid fibrils in the onset and progression of amyloid diseases. [ABSTRACT FROM AUTHOR]

A family of bis[(R or S)‐N‐1‐(Ar)ethylsalicylaldiminato‐κ2N,O]‐Δ/Λ‐zinc(II) {Ar=C6H5 (ZnRL1 or ZnSL1), p‐CH3OC6H4 (ZnRL2 or ZnSL2) and p‐ClC6H4 (ZnRL3 or ZnSL3)} compounds was synthesized and investigated by multiple methods. They feature Λ/Δ‐chirality‐at‐metal induction along the pseudo‐C2 axis of the molecules. The chirality induction is quantitative in the solid state, explored by X‐ray crystallography and powder X‐ray diffraction (PXRD), where R or S‐ligated complexes diastereoselectively yield Λ or Δ‐configuration at the metal. On the other hand, Λ and Δ‐diastereomers co‐exist in solution. The Λ⇆Δ equilibrium is solvent‐ and temperature‐dependent. Electronic circular dichroism (ECD) spectra confirm the existence of a diastereomeric excess of Λ‐ZnRL1−3 or Δ‐ZnSL1−3 in solution. DSC analysis reveals thermally induced irreversible phase transformation from a crystalline solid to an isotropic liquid phase. ECD spectra were reproduced by DFT geometry optimizations and time‐dependent DFT (TD‐DFT) calculations, providing ultimate proof of the dominant chirality atmetal in solution. [ABSTRACT FROM AUTHOR]

The vast majority of racemic solutions of chiral compounds apparently crystallize at room temperature in non-Sohncke space groups as racemic crystals. However, kryptoracemic crystals composed of nearly enantiomeric pairs occasionally crystallize at room temperature, or appear as low-temperature phases, in Sohncke space groups. As a complement to the previously published catalog of organic kryptoracemates [Fábián & Brock (2010). Acta Cryst. B 66, 94-103], 1412 chiral organometallic crystal structures have now been extracted from the Cambridge Structural Database and analyzed. 26 are listed herein as credible kryptoracemates. The possible influence of temperature is discussed, together with some problems in characterizing and classifying these structures. [ABSTRACT FROM AUTHOR]

The relationship between the coordination geometry and photophysical properties of trans‐bis[(β‐iminomethyl)naphthoxy]platinum(II) was investigated both experimentally and theoretically. A series of platinum(II) complexes with differently substituted iminomethyl groups were synthesized, and their photophysical properties were examined in solution, in the crystalline, and in the PMMA film‐dispersed state, respectively (PMMA=poly(methyl methacrylate)). These complexes showed structure‐dependent emission spectra, in which the color of the luminescence in the crystalline state varied over a range of about 40 nm depending on the specific bowl‐shaped molecular structure. The chiral complexes with (R,R)‐ and (S,S)‐configurations were found to have structure‐dependent chiroptical properties both in solution and the PMMA film‐dispersed state such that the intensity of circular dichroism (CD) and circularly polarized luminescence (CPL) were enhanced with bulky cyclic substituents at the nitrogen atoms. A theoretical study using density functional theory (DFT) and time‐dependent (TD)‐DFT calculations revealed that the enhancement of chiroptical responses is due to the amplification of the magnetic dipole moment caused by the distortion of the square planar geometry. [ABSTRACT FROM AUTHOR]

In the title polymer, [Pb(C9H4O6)] n, the asymmetric unit contains a monomer of a PbII cation with a doubly deprotonated 3-carboxybenzene-1,2-dicarboxylate dianion (1,2,3-Hbtc2−). Each PbII centre is seven-coordinated by seven O atoms of bridging carboxy/carboxylate groups from five 1,2,3-Hbtc2− ligands, forming a distorted pentagonal bipyramid. The PbII cations are bridged by 1,2,3-Hbtc2− anions, yielding two-dimensional chiral layers. The layers are stacked above each other to generate a three-dimensional supramolecular architecture via a combination of C-H...O interactions. The thermogravimetric and optical properties are also reported. [ABSTRACT FROM AUTHOR]

The Front Cover demonstrate the photocontrol of selective reflection colors that originate from the self‐organized helical structure of chiral nematic liquid crystals (N*LCs) by using closed‐/open‐type dopants. The drastic structure changes of the dopants by light stimuli enable reversible broad‐spectrum control of selective reflections of N*LCs with opposite helical sign. In their Full Paper, H. Nishikawa et al. focus on reversible broad‐spectrum control of selective reflections of opposite‐handed chiral nematics by using new chiral dopants. More information can be found in the Full Paper by H. Nishikawa et al. on page 710 in Issue 6, 2017 (DOI: 10.1002/open.201700121). [ABSTRACT FROM AUTHOR]

Invited for this month's cover picture is the groups of Professor Hirotsugu Kikuchi and Dr. Yasushi Okumura at the Institute for Materials Chemistry and Engineering at Kyushu University (Japan). External dynamic control of molecular self-organized superstructures with unique features has been researched, as these structures are applicable to chiral molecular devices. The cover picture shows photocontrol of selective reflection color that originated from the self-organized helical structure of chiral nematic liquid crystals (N*LCs) using closed-/open-type dopants. The drastic structure changes of the dopants by light stimuli enable reversible broad-spectrum control of selective reflections of N*LCs with opposite helical sign. Read the full text of the Full Paper at . [ABSTRACT FROM AUTHOR]

Self‐assembly, as a typical bottom‐up strategy for the fabrication of functional materials, has been applied to fabricate chiral materials with subtle chiral nanostructures. The chiral nanostructures exhibit great potential in asymmetric catalysis, chiral sensing, chiral electronics, photonics, and even the realization of several biological functions. According to existing studies, the supramolecular chirality transfer process combined with hierarchical self‐assembly plays a vital role in the fabrication of multiscale chiral structures. This progress report focuses on the hierarchical self‐assembly of chiral or achiral molecules that aggregate with asymmetric spatial structures such as twisted bands, helices, and superhelices in different environments. Herein, recent studies on the chirality transfer induced self‐assembly based on a variety of supramolecular interactions are summarized. In addition, the influence of different environments and the states of systems including solutions, condensed states, gel systems, interfaces on the asymmetric hierarchical self‐assembly, and the expression of chirality are explored. Moreover, both the driving forces that facilitate chiral bias and the supramolecular interactions that play an important role in the expression, transfer, and amplification of the chiral sense are correspondingly discussed. [ABSTRACT FROM AUTHOR]

The construction and control of high‐order coupled vortices are a significant challenge for promoting the application of magnetic vortices. Thus far, only double‐coupled vortices have been produced and modulated in some ferromagnetic nanostructures. Here, an effective approach is provided to obtain a high‐order coupled vortex structure by using a chiral nanostructure. Double‐vortex, triple‐vortex, and n‐vortex chains can be successfully constructed using structured Fe4N nanostrips and bias nanomagnets. The designed chiral nanostructure cannot only control the transport and hybridization of vortices but also modulate the domain walls of the vortex chain for spin wave (SW) propagation. At the exciting frequency of 1.2 GHz, the SW propagates along the domain walls formed in the vortex chain. Upon increasing the frequency to 5.0 GHz, the SW gradually spreads from the domain walls into domains. This technique will present a new perspective for the design and application of magnetic vortex‐based devices. [ABSTRACT FROM AUTHOR]

The weakly coordinated anionic nitrate ligands in a centrosymmetric Ag20 cluster are replaced in a stepwise manner by chiral amino acids and two achiral luminescent sulfonic‐group‐containing ligands while nearly maintaining the original silver(I) cage structure. This surface engineering enables the atomically precise Ag20 clusters to exhibit the high‐efficiency synergetic effects of chirality and fluorescence, producing rare circularly polarized luminescence among the metal clusters with a large dissymmetry factor of (|glum|) ≈ 5 × 10−3. This rational approach using joint functional ligands further opens a new avenue to diverse multifunctional metal clusters for promising applications. [ABSTRACT FROM AUTHOR]

Nonenzymatic oxidative processes in living organisms are among the inevitable consequences of respiration and environmental conditions. These oxidative processes can lead to the formation of two stereoisomers (R and S) of methionine sulfoxide, and the redox balance between methionine and methionine sulfoxide in proteins has profound implications on their function. Methionine oxidation can be reverted enzymatically by methionine sulfoxide reductases (Msrs). The two enzyme classes known to fulfill this role are MsrA, reducing the (S)‐isomer, and MsrB, reducing the (R)‐isomer of methionine sulfoxide. They are strictly stereoselective and conserved throughout the tree of life. Under stress conditions such as stationary phase and nutrient starvation, Escherichia coli upregulates the expression of MsrA but a similar effect has not been described for MsrB, raising the conundrum of which pathway enables reduction of the (R)‐isomer of methionine sulfoxide in these conditions. Using the recently developed chiral fluorescent probes Sulfox‐1, we show that in stationary phase‐stressed E. coli, MsrA does have a stereocomplementary activity reducing the (R)‐isomer of methionine sulfoxide. However, this activity is not provided by MsrB as expected, but instead by the DMSO reductase complex DmsABC, widely conserved in bacteria. This finding reveals an unexpected diversity in the metabolic enzymes of redox regulation concerning methionine, which should be taken into account in any antibacterial strategies exploiting oxidative stress. Database: The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD013610. [ABSTRACT FROM AUTHOR]

This study proposes a mathematical model and a technique for the electrodynamic analysis of a microstrip antenna with a chiral substrate based on the left-handed spirals. It describes the design of such an antenna and presents its impedance characteristics for various parameters. It has been shown that the use of a chiral substrate improves the mass-dimensional characteristics of the microstrip antennas. [ABSTRACT FROM AUTHOR]

Abstract: A chemo‐ and biocatalytic cascade approach was applied for the stereoselective synthesis of hydroxy ketones and the corresponding 1,3‐diols. A new class of tridentate N,N,O ligands was used with copper(II) complexes for the asymmetric β‐borylation of α,β‐unsaturated compounds. The complex containing ligand L5 emerged as the best performer, and it gave the organoborane derivatives with good ee values. The corresponding keto–alcohol compounds were then bioreduced by yeasts. The biotransformation set up with Rhodotorula rubra allowed (R)‐keto–alcohols and (S,S)‐diols to be obtained with up to 99 % ee and up to 99 % de in favor of the anti enantiomers. [ABSTRACT FROM AUTHOR]

Abstract: A three‐dimensional π‐conjugated chiral cage with six [5]helicene units (a triple helicene cage) was synthesized for the first time. Taking advantage of the Yamamoto coupling reaction, the triflate‐substituted triple [5]helicene, a strained and preorganized precursor, was dimerized to afford the target compound. Single‐crystal X‐ray diffraction analysis revealed the unique structural features of the triple helicene cage: a cage‐shaped rigid structure with outer helical grooves and an inner chiral cavity. All‐P and all‐M enantiomers were separated successfully by HPLC over a chiral column and their chiroptical properties were characterized by circular dichroism spectra. [ABSTRACT FROM AUTHOR]

Phosphine is conformationally stable because of the high inversion energy barrier of the phosphorus atom, which allows the phosphorus atom to become a chiral center. Thus, enantiopure P-stereogenic 12-, 15-, 18-, and 21-membered aliphatic phosphines 'diphosphacrowns' were synthesized from secondary P-stereogenic bisphosphine as a chiral building block. Their complexation behaviors with alkali metal ions are investigated in comparison with benzo-18-diphosphacrown-6 and benzo-18-crown-6. 15-, 18-, and 21-Membered diphosphacrowns captured alkali metal ions to form 1:1 metal complexes. Unique guest selectivity was observed, as diphosphacrowns encapsulated smaller alkali metal ions than common crown ethers; for example, 18-membered diphosphacrowns interacted more strongly with Na+ than K+. The difference in guest selectivity between diphosphacrowns and common crown ethers is speculated to result from the cavity size, owing to the large phosphorus atom as well as steric hindrance around the phosphine moiety. [ABSTRACT FROM AUTHOR]

Reactions of calcium bromide with enantiopure and racemic proline in aqueous solution lead to two solids in which the zwitterionic amino acid acts as a bridging ligand between neighbouring cations. Depending on the chirality of the amino acid, topologically very different products are obtained. With racemic proline, bromide acts as a simple uncoordinated counter-anion for the cationic heterochiral chains in catena-poly[[aquacalcium(II)]-μ-aqua-μ3-DL-proline-μ2-DL-proline], {[Ca(C5H9NO2)2(H2O)2]Br2} n. In agreement with chemical intuition, only carboxylate and aqua O atoms coordinate the alkaline earth cation in a low-symmetry arrangement. In contrast, L-proline affords the two-dimensional network poly[dibromidobis(μ2-L-proline)calcium(II)], [CaBr2(C5H9NO2)2] n, with an unexpected CaBr2 unit in a more regular coordination sphere. [ABSTRACT FROM AUTHOR]

Acidic hydrogen containing 2-isocyano-4-methylphenyl diphenylacetate, C22H17NO2, (I), was synthesized by the base-promoted reaction between 5-methylbenzoxazole and diphenylacetyl chloride. Achiral (I) crystallizes in the chiral P212121 space group. The C[triple-bond]N bond length is 1.164 (2) Å and the angle between the OCO and 2-isocyano-4-methylphenyl planes is 69.10 (16)°. Molecules are linked via C=O...Hphenyl and bifurcated N[triple-bond]C...Hphenyl/N[triple-bond]C...Hmethine hydrogen bonds, forming one-dimensional arrays. [ABSTRACT FROM AUTHOR]

In connection with a research program involving the synthesis, structure determination, reactivity and ability to coordinate to metal centres of chiral bisphosphine ligands, we have synthesized and structurally characterized, by means of single-crystal X-ray diffraction analysis, the title compound {systematic name: ( S, S)-(ethane-1,2-diyl)bis[(2-methylphenyl)phenylphosphane], abbreviated as o-tolyl-DiPAMP}, C28H28P2. So far, neither the free bisphosphine (DiPAMP) nor analogues that incorporate the ethylenebisphosphine frame have had their crystal structures reported. The investigated compound forms crystals which are isostructural with the bisphosphine dioxide analogue [King et al. (2007). Acta Cryst. E 63, o3278], despite the involvement of the dioxide in C-H...O(=P) hydrogen bonds and the lack of similar hydrogen bonds in the investigated crystal structure. In both molecules, the P-C-C-P chain is in a trans conformation, extended further at both ends by one of the two P-C ipso bonds. The planes of the phenyl and o-tolyl rings attached to the same P atom are nearly perpendicular to one another. Both crystal structures are mainly stabilized by dispersive interactions. [ABSTRACT FROM AUTHOR]

Two macrotricyclic ligands composed of two face-to-face octadentate metal chelates were synthesized. These cage-shaped disodium complexes had special recognition ability for various counter anions. Specific chiral dicarboxylates bound to the complexes within the cavity and exhibited chirality induction properties. For instance, N-Boc-Asp dianion strongly induced circular dichroism (CD) signals, but N-Boc-Glu dianion, which is one carbon longer, did not. [ABSTRACT FROM AUTHOR]

The molecules in ( E)- N-(3,4,5-trimethoxybenzylidene)naphthalen-1-amine, C20H19NO3, (I), and its reduction product N-(3,4,5-trimethoxybenzyl)naphthalen-1-amine, C20H21NO3, (II), are both conformationally chiral, but (I) crystallizes in a centrosymmetric space group, while (II) crystallizes with just one conformational enantiomer in each crystal. A combination of two C-H...O hydrogen bonds links the molecules of (I) into sheets containing a single type of R66(44) ring, and these sheets are linked into a continuous three-dimensional array by a single π-π stacking interaction. The molecules of (II) are linked into complex sheets by a combination of N-H...O, C-H...O and C-H...π(arene) hydrogen bonds. [ABSTRACT FROM AUTHOR]

Aim To examine, at a global scale, patterns in the direction in which climbing plants twine. We tested three hypotheses: (1) that twining direction is determined randomly; (2) that twining direction is determined by apices following the apparent movement of the sun across the sky; and (3) that twining direction is determined by the Coriolis effect. Location Seventeen sites spanning nine countries, both hemispheres and 65° of latitude. Methods Twining direction was recorded for the first c. 100 stems encountered along transects through natural vegetation at each site. Results Ninety-two per cent of the 1485 twining stems we recorded grew in right-handed helices, i.e. they twined in an anticlockwise direction. This is significantly ( P < 0.001) different from random. The proportion of stems twining right-handedly (anticlockwise) was independent of both latitude ( P= 0.33) and hemisphere ( P= 0.63). These data are inconsistent with the idea that twining direction is determined by either the relative passage of the sun through the celestial sphere or by the Coriolis effect. Thus, we reject all three of our hypotheses. Main conclusions The predominance of right-handed helical growth in climbing plants cannot be explained by hypotheses attempting to link plant growth behaviour and global location. One alternative hypothesis for our findings is that the widespread phenomenon of anticlockwise twining arises as a function of microtubule orientation operating at a subcellular level. [ABSTRACT FROM AUTHOR]

Molecules of (R)-2,3,4,5-tetrahydro-2,2,4-trimethyl-1,5-benzothiazepine, C12H17NS, are linked into spiral C(5) chains by a single N-H···S hydrogen bond, while molecules of rac5-benzoyl-2,3,4,5-tetrahydro-2,2,4-trimethyl-1,5-benzothiazepine, C19H21NOS, are linked into zigzag chains by a CH···π(arene) hydrogen bond. . [ABSTRACT FROM AUTHOR]

The 20-membered ring in 1,7,11,17-tetraoxa-2,6,12,16-tetraazacycloeicosane tetrahydrochloride, C12H32N4O44·4Cl-, adopts an endo conformation, while the 18-membered ring in 1,6,10,15-tetraoxa-2,5,11,14-tetraazacyclooctadecane tetrahydrochloride, C10H28N4O44+·4Cl-, lies about an inversion centre and adopts a symmetrical conformation. In the crystal structures of both compounds, the cations and chloride anions are linked by N-H···Cl hydrogen bonds into planar sheets of molecules; the sheets are linked into three-dimensional networks via C-H···Cl hydrogen bonds. [ABSTRACT FROM AUTHOR]

Studies the structures of the compounds {Bis[(S)-2-(4-tert-buyl-4,5-dihydro-oxazol-2-yl)phenyl]phenylphoshine-κ²N,P}(1,3-dimethyl-π-allyl-κ[sup 3]C)-palladium(II) hexafluorophosphate and (S)[sub P]-{bis[(S)-2-(4-tert-butyl-4,5-dihydrooxazol-2-yl)phenyl]-phenylphosphin e-κ²N,P}dichloro-palladium(II). Data showing that the bis(dihydro-oxazolyl)phosphine ligand is N,P-bidentate, with S chirality on the P atom.

Focuses on chirality-induced forbidden reflections or anisotropy of the tensor of the susceptibility in X-ray resonant scattering. Structure amplitudes of Bragg reflections; Distinction between the global anisotropy/chirality of a crystal and the local atomic anisotropy/chirality accessible only via X-ray diffraction.

Lipase from Candida cylindracea catalyzes the acidolysis between racemic 2-methylalkanoates and fatty acids in heptane with a preference for the (S)-configurated esters. Velocity and enantioselectivity of the acyl transfer are strongly influenced by the structures of the initial substrates. The potential of this strategy for kinetic resolution of the enantiomers of chiral 2-methylalkanoates is demonstrated. Limitations of the procedure due to the reversible character of the reaction are discussed. [ABSTRACT FROM AUTHOR]

Both methionine residues in phospholipase A2 (PLA2) from porcine pancreas have been replaced by leucines with retention of full enzymatic activity. The methionine-less mutant has been expressed as a Cro-LacZ fusion protein in Escherichia coli, from which a pro-PLA2 was liberated by chemical cleavage with CNBr. The general applicability of CNBr cleavage of proteins lacking mcthionine residue(s) was demonstrated by replacing the single Met8 in human platelet phospholipase A2 (HPPLA2) by a leucine residue, and the introduction of a methionine at a position just preceding the HPPLA2 sequence. This protein was expressed in E. coil as a 68-kDa Cro-LacZ fusion protein. CNBr cleavage liberated the HP-PLA2 fragment which was reoxidized in vitro. The [Met8→ Leu]HP-PLA2 is monomeric in aqueous solutions, requires calcium ions in the millimolar range for enzymatic activity and has optimal activity around pH 8, ρ-Bromophenacyl bromide rapidly inactivates the enzyme with calcium ions having a protective effect. The highest specific activities, 2400 U/mg and 9300 U/mg, were found with pure micelles of 1,2-dioctanoyl-sn-glycero-3-phosphoglycol and with mixed micelles of taurodeoxycholate and 1,2-dioctanoyl-sn-glycero-3-phosphoglycol, respectively. In mixed micelles the activity on dioleoyl phospholipids decreases in the order phosphatidylglycerol > phosphatidylethanolamine » phosphatidylcholine. The enzyme has low activity on monomeric 1,2diheptanoyl-sn-glycero-3-phosphocholine as a substrate, but high activity on micelles with a distinct jump in activity at the critical micellar concentration. The binding of the HP-PLA2, porcine pancreatic PLA2 and PLA2 from Naja melanoleuca venom to lipid/water interfaces was determined with micellar solutions of the substrate analog n-hexadecylphosphocholine. The HP-PLA2 has a high apparent Kd (2 mM) compared to pancreatic (0.2 mM) and venom (0.03 mM) PLA2. In mixed micelles of taurodeoxycholate and 1,2-didodecanoyl-sn-glycero-3-phosphocholine, the competitive inhibition of HP-PLA2 by the R and S enantiomers of 2-tetradecanoylaminohexanol-l-phosphocholine, its phosphoglycol, and its phosphoethanolamine derivatives were tested. The S enantiomers are only weak inhibitors, whereas the R enantiomers are potent inhibitors. The inhibitory power depends on the nature of the polar head group and increases in the order phosphocholine « phosphoethanolamine < phosphoglycol. The best inhibitor, (R)-2-tetradecanoylaminohexanol-l-phosphoglycol, binds 2200 times stronger than the substrate to the HP-PLA2 active site. [ABSTRACT FROM AUTHOR]

The enantiomeric error frequency of aspartate aminotransferase (mitochondrial isoenzyme from chicken) was assessed by adding the enzyme in high concentration (0.89 mM) to a mixture of L-glutamate and 2-oxoglutarate (12 and 1.2 mM, respectively, at pH 7.5 and 25°C). The substrates continuously undergo the transamination cycle under these conditions. Thereby, L-glutamate is progressively racemized, a 1:1 ratio of two enantiomers being reached within 240 h. The enantiomeric error frequency, i.e. the ratio of the rate of D-glutamate production and the rate of the transamination reaction with glutamate and 2-oxoglutarate as substrates, is 1.5 x 10-7. D-Glutamate is also converted to a 1:1 racemic mixture. The racemizing activity of a mixture of free pyridoxal 5′-phosphate and pyridoxamine 5′-phosphate is about two orders of magnitude lower than that of aspartate aminotransferase. The error frequency of the enzyme in the case of the C4 substrate pair aspartate and oxalacetate is 3.4 x 10-8, i. e. 4 times lower than that with the C5 substrate pair. [ABSTRACT FROM AUTHOR]

The article presents abstracts on topics related to organic chemistry including the introduction of chirality by the ring-expansion, the classical reactions' metal-mediated analogues, and the aryl triflates conversion into fluorides.

In the title compound, C14H10N2O5, the mol­ecules are linked by a combination of one N—H⋯O and one O—H⋯O hydrogen bond into sheets containing a single type of R44(22) ring. [ABSTRACT FROM AUTHOR]

Mol­ecules of the title compound, C26H18Cl3NO2, are linked into sheets of R44(26) rings by a combination of C—H⋯N and C—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the title compound, C11H10N4O·H2O, there are five independent hydrogen bonds, of O—H⋯O, O—H⋯N and N—H⋯O types, which link the components into complex sheets parallel to (001). [ABSTRACT FROM AUTHOR]

In the title adduct, C6H12N2·C7H8O2, the orcin and 1,4diazabicyclo[2.2.2]octane moieties are held together by OH···N hydrogen bonds. One-dimensional chiral hydrogenbonded chains are formed along the b axis. Neighbouring chains are held together principally by van der Waals interactions and are interrelated by translation, resulting in a chiral layer. [ABSTRACT FROM AUTHOR]

The molecular structures of the title compounds, C25H46N6 and C15H30N6, respectively, show the two guanidyl moieties each connected by propyl bridges. The different substitution pattern of the guanidyl groups has no influence on the distinct localization of their C=N double bonds. Both compounds exhibit approximate twofold symmetry and the crystal packing shows no prominent hydrogen-bonding interactions. [ABSTRACT FROM AUTHOR]

The title compound, C13H9NO5, crystallizes in space group P&1macr;, with Z' = 3. The molecules are linked by O-H···O hydrogen bonds [H···O = 1.79-1.81 Å, O···O = 2.625 (3)-2.648 (3) and O-H···O = 172-176°] into two types of R2²(8) dimer, only one of which is centrosymmetric. An extensive series of soft hydrogen bonds, of C-H···O and C-H···π(arene) types, links the dimers into a three-dimensional framework. [ABSTRACT FROM AUTHOR]

Molecules of the title compound (also known as 2-bromoresorcinol), C6H5BrO2, are essentially planar and possess normal geometrical parameters. The crystal packing is influenced by O-H···O and O-H···O/Br hydrogen bonds and π-π stacking interactions, resulting in a distinctive highsymmetry structure containing R44(8) rings and helical C(2) chains. [ABSTRACT FROM AUTHOR]

The crystal structure of the title compound, alternatively called 1,2,3-triiodo-5-(triphenylmethyl)benzene, C25H17I3, is analysed in terms of I···I and I···π interactions and the herring-bone T motif between phenyl groups. There are two molecules in the asymmetric unit, denoted A and B. Inversionrelated A molecules are connected via an I···π interaction (3.641 Å, to a C-C bond mid-point) to form an I···π dimer, and these dimers are connected through symmetry-independent B molecules via I···I [3.5571 (15) Å] and I···π (3.561 Å, to a C-C bond mid-point) interactions. [ABSTRACT FROM AUTHOR]

Molecules of the title compound, C21H30N2O6S2, adopt a skeletal conformation which does not possess even approximate internal symmetry. The molecules are linked by two NH···O=S hydrogen bonds [H···O = 1.97 Å (×2), N··· 2.865 (2) and 2.864 (2) Å, and N-H···O = 160 and 159°] into molecular ladders, alternatively described as chains of edgefused R2²(20) rings. [ABSTRACT FROM AUTHOR]

A carbohydrate-derived optically active P-chiral dioxophenylphospholane-borane complex, C27H32BO6P, was prepared from bis(diethylamino)phenylphosphine and methyl 2,6-diO-benzyl-½-D-galactopyranoside. The phosphinite was prepared with high diastereoselectivity and in good yield. The absolute configuration (R) at the P atom was deduced from the known configuration of the sugar moiety. Weak intermolecular interactions link the molecules into a threedimensional network. [ABSTRACT FROM AUTHOR]