Search

Abstract: Ferroelasticity involves the generation of spontaneous strain in a solid by the application of mechanical stress. The phenomenon has been well‐studied in metal alloys but relatively neglected in organic solid‐state chemistry. Herein we present multiple discrete modes of mechanical twinning and a mechanistic analysis of ferroelasticity in 1,4‐diethoxybenzene. Single crystals of the compound can be almost freely deformed, as multiple different twin domains are generated simultaneously. Within each domain, single‐crystal character is preserved. Such extremely versatile, ferroelastic deformability is unprecedented in single crystals of any kind and defies the fragility and anisotropic mechanical behaviour of most organic crystals. The dissipated energy and critical stress associated with twinning deformation in 1,4‐diethoxybenzene suggests that organic solids could be developed for absorbing weak mechanical shocks in such applications as mechanical damping and soft robotics. [ABSTRACT FROM AUTHOR]

Abstract: Ferroelasticity involves the generation of spontaneous strain in a solid by the application of mechanical stress. The phenomenon has been well‐studied in metal alloys but relatively neglected in organic solid‐state chemistry. Herein we present multiple discrete modes of mechanical twinning and a mechanistic analysis of ferroelasticity in 1,4‐diethoxybenzene. Single crystals of the compound can be almost freely deformed, as multiple different twin domains are generated simultaneously. Within each domain, single‐crystal character is preserved. Such extremely versatile, ferroelastic deformability is unprecedented in single crystals of any kind and defies the fragility and anisotropic mechanical behaviour of most organic crystals. The dissipated energy and critical stress associated with twinning deformation in 1,4‐diethoxybenzene suggests that organic solids could be developed for absorbing weak mechanical shocks in such applications as mechanical damping and soft robotics. [ABSTRACT FROM AUTHOR]

In solid-state science, most changing phenomena have been mysterious. Furthermore, the changes in chemical composition should be added to mere physical changes to also cover the chemical changes. Here, the first success in characterizing the nature of gas inclusion in a single crystal is reported. The gas inclusion process has been thoroughly investigated by in situ optical microscopy, single-crystal X-ray diffraction analyses, and gas adsorption measurements. The results demonstrated an inclusion action of a first-order transition behavior induced by a critical concentration on the phase boundary. The transfer of phase boundary and included gas are strongly related. This relationship can generate the dynamic features hidden in the inclusion phenomena, which can lead to the guest capturing and transfer mechanism that can apply to spatiotemporal inclusion applications by using host solids. [ABSTRACT FROM AUTHOR]

In solid-state science, most changing phenomena have been mysterious. Furthermore, the changes in chemical composition should be added to mere physical changes to also cover the chemical changes. Here, the first success in characterizing the nature of gas inclusion in a single crystal is reported. The gas inclusion process has been thoroughly investigated by in situ optical microscopy, single-crystal X-ray diffraction analyses, and gas adsorption measurements. The results demonstrated an inclusion action of a first-order transition behavior induced by a critical concentration on the phase boundary. The transfer of phase boundary and included gas are strongly related. This relationship can generate the dynamic features hidden in the inclusion phenomena, which can lead to the guest capturing and transfer mechanism that can apply to spatiotemporal inclusion applications by using host solids. [ABSTRACT FROM AUTHOR]

Deformation twinning, which is a type of plastic deformation, has been particularly investigated in metal materials. However, only a few examples are found in organic solids. We observed mechanical twinning deformation on a simple ferrocene crystal, which is considered the most representative organometallic compound, and evaluated the crystal structures under the twinning state and the shear deformation characteristics by single-crystal X-ray diffraction analysis and uniaxial compression tests. The structural analyses showed the molecular rearrangement during twinning deformation. The shear deformation properties depend on the rotational mobility of the cyclopentadienyl rings in comparison with crystals of nickelocene, ruthenocene, and mixed crystals of ferrocene/ruthenocene. [ABSTRACT FROM AUTHOR]

A novel microporous single crystal of [Cu(ii)2(1-NA)4(pyz)]n (1-NA: 1-naphthoate, pyz: pyrazine) exhibited bending and straightening action on a macroscopic scale during the first-order crystal phase transition induced by methanol vapor sorption. [ABSTRACT FROM AUTHOR]

Superelastic materials (crystal-to-crystal transformation pseudo elasticity) that consist of organic components have not been observed since superelasticity was discovered in a Au-Cd alloy in 1932. Superelastic materials have been exclusively developed in metallic or inorganic covalent solids, as represented by Ti-Ni alloys. Organosuperelasticity is now revealed in a pure organic crystal of terephthalamide, which precisely produces a large motion with high repetition and high energy storage efficiency. This process is driven by a small shear stress owing to the low density of strain energy related to the low lattice energy. [ABSTRACT FROM AUTHOR]

Superelastic materials (crystal-to-crystal transformation pseudo elasticity) that consist of organic components have not been observed since superelasticity was discovered in a Au-Cd alloy in 1932. Superelastic materials have been exclusively developed in metallic or inorganic covalent solids, as represented by Ti-Ni alloys. Organosuperelasticity is now revealed in a pure organic crystal of terephthalamide, which precisely produces a large motion with high repetition and high energy storage efficiency. This process is driven by a small shear stress owing to the low density of strain energy related to the low lattice energy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Soft crystals exhibiting luminescence chromism based on stress magnitude are reviewed. • Some ground crystalline solids spontaneously recover initial luminescence property. • Ultra-high pressure reducing π-π stacking distance can control luminescence color. • Bending elastic crystals can cause reversible luminescence chromism. • "Superelastochromism" by reversible crystal-to-crystal phase transfer is reviewed. Mechano-responsive luminescence, or mechanochromic luminescence (MCL), is a type of luminescence that can be reversibly controlled by the addition of mechanical stimuli. Organic materials exhibiting MCL have been an ongoing area of development since the early 2000s, and the number of reports into such materials has been steadily increasing. While the majority of MCL systems rely on the brittle nature of organic crystalline solids, there is a growing interest in "flexible" organic crystals that exhibit mechanical bending or shape deformation owing to their elasticity/plasticity. Such non-destructive deformed crystals may exhibit a new type of MCL that can be controlled by the magnitude of the force stress. In this review, we describe MCL systems capable of the spontaneous recovery of changes in their luminescent properties in response to the loading/unloading of mechanical stress. We particularly focus on the MCL of flexible crystals based on the density gradient of molecular packing (i.e., elastic and plastic crystals) and an emerging system known as "superelastochromism," which is based on spontaneously reversible crystal polymorphism. This emerging research area has the potential to play an important role in the promotion of next-generation soft crystals. [ABSTRACT FROM AUTHOR]

Abstract: A homoleptic hexanuclear Cu cluster, [(Cu(DSB)(CBT))2(Cu2Br)2][PPh4]2 (1-PPh4 ) [DSB=2,3-disulfidobenzoate; CBT=3-carboxybenzene-1,2-bis(thiolate)] was synthesized as dark green crystals by the reaction of CuCl2 with 2,3-dimercaptobenzoic acid in acetate buffer solution. The X-ray crystal study of 1-PPh4 revealed its unique structural features: (1) one of two types of crystallographically distinct Cu centers adopted a square planer geometry and the other center had a tetrahedral geometry, and (2) intermolecular H-bonding interactions connected between carboxylic acid group of CBT and the carboxylate group of DSB led to the construction of an unprecedented topologic architecture of a zigzag patterned infinite sheet. In addition, taking into account the total charge of the molecule, which contained 2,3-disulfidobenzoate and 3-carboxybenzene-1,2-bis(thiolate), and the diamagnetic nature of 1-PPh4 , 1-PPh4 led to it is assignment as a mixed-valence Cu(I)/Cu(III) cluster. Such mixed valence states of Cu atoms were also examined by density functional theory calculation. [Copyright &y& Elsevier]

For the purpose of investigating the correlation between host gas adsorption ability and structural flexibility, the combination of metal benzoate complexes [M2II(bza)4] (MII = Rh (a), Cu (b); bza = benzoate) and pyrazine derivatives (pyz = pyrazine (1), 2-mpyz = 2-methylpyrazine (2), 2,3-dmpyz = 2,3-dimethylpyrazine (3)) yields a series of one-dimensionally assembled complexes. The study of the adsorption properties of this series was examined for CO2, H2, N2, O2, and Ar gases at 195 K (CO2) or at 77 K (all others). The adsorption manners of these complexes are similar for each gas, while the pressure at which adsorption started or rapidly grew increased with a rise in the number of methyl groups in the case of adsorbable gases. The maximum amount of adsorption was a positive integer, e.g., 3 molecules per M2 unit for 1 and 2 and 2 molecules per M2 unit for 3 in the case of CO2 adsorption for all complexes at 0.1 MPa of adsorbable gases. Structural transformation was observed accompanying gas adsorption. This transformation was observed when the adsorption amount reached 1 molecule per M2 unit, suggesting a correlation of the adsorption amount and dynamic adsorption behavior. Single-crystal X-ray analyses of nonincluded crystals and CO2 inclusions for all hosts (1-3) revealed that large structural changes occurred through CO2 adsorption to increase the inner space for adsorption gases, depending on the substituents on the pyrazine ring. These facts were confirmed as a transition by DSC measurements using a mixed CO2/N2 gas atmosphere. Solid-state ¹H and ²H NMR studies of the crystalline sample of 1a and its partially deuterated samples of 1a′ (deuterated phenyl group) and 1a″ (deuterated pyrazine) revealed rapid 180°-flip motions of the aromatic rings of the host skeletons, which form the walls of the channels. These "rotating" motions would help the diffusion of CO2 molecules through a narrow channel at relatively low pressure. Indeed, the motions of phenyl groups and methyl-substituted pyrazine moieties of phenyl deuterated 3a were confirmed to be very slow by solid-state ¹H and ²H NMR spectra, where the amount of adsorbed gas molecules was small for 3a at 0.1 MPa of CO2. [ABSTRACT FROM AUTHOR]

In order to investigate the methane-included condition in porous materials and its response to external stimuli, the methane adsorption state of a single-crystal adsorbent, [Cu(II)2(bza)4(pyz)]n, was studied by single-crystal X-ray analysis and adsorption measurement as functions of temperature (90-298 K) and pressure (3.2-42 MPa). The included methane molecule was encapsulated into the channel of the adsorbent and stabilized through the interactions between the surrounding aromatic rings. The single-crystal host readily adsorbed methane gas and easily achieved the saturated condition with the included amount of 2 methane molecules per Cu2 unit. The results from the gas adsorption measurements were consistent with the results from the crystallographic structures. Single-crystal X-ray analysis showed that the methane-saturated crystal has a critical temperature of the crystal phase transition from the C2/c to the P−1 space group between 150 and 200 K. In temperature swinging, the thermal factors of the atoms of the guest methane and host skeleton monotonically decreased as the temperature decreased. In contrast, in pressure swinging at 298 K, the thermal factors gradually decreased as the pressure increased, after passing 11 MPa only the thermal factor of the guest methane decreased in response to an increase in gas pressure while those of the host skeleton remained almost constant. It is suggested that the channel acts as "force guide," propagating the outside gas pressure into the crystal inside through a guest-guest interaction in the included gas array. In addition, the difference in the pressure dependencies of the thermal factors on the host and guest suggested that the structural susceptibility to external gas pressure and temperature is different between open porous solids and non-porous solids. [ABSTRACT FROM AUTHOR]

We report the magnetic behaviors of O2 molecules, which aligned in the channels of four types of single-crystal adsorbents, [M2(bza)4(pyz)]n (bza = benzoate; pyz = pyrazine; M = RhII (1a) and CuII (1b)) and [M2(bza)4(2-mpyz)]n (2-mpyz = 2-methylpyrazine; M = RhII (2a) and CuII (2b)). The X-ray single-crystal structures at various temperatures from 10 to 298 K were determined for O2-included crystals of 1a and 2a. All adsorbed O2 molecules exhibited abnormal magnetic phases above 4 T in the temperature range around 55-105 K. The magnetic behaviors of adsorbed O2 molecules between four inclusions were discussed. The existence of the metastable state, which was also suggested by hysteresis on the M-H curves, was revealed by analysis of the time course of the magnetization. Considering that the abnormal magnetic behavior occurred at relatively high temperatures and a low magnetic field, it was suggested that these behaviors were induced because of the changes of magnetic interaction of included O2 aggregates involving transformation which is supported by the surrounding of the channels of the single-crystal hosts under the applied magnetic field. [ABSTRACT FROM AUTHOR]

Abstract: Adsorption properties of magnetic species in nano-porous crystals were studied theoretically. The crystal [Rh2bza4pyz] n , which had been reported by Mori, Takamizawa and their co-workers in detailed, was employed in this study. As adsorbed magnetic radicals, a oxygen molecule (O2; S =1) was treated. From the results by our MO calculations, weak magnetic interactions between O2 molecules in cavities existed. Two types of magnetic interactions (ferro- and antiferro-magnetic) made alignment of trimer spin structure. Our theoretical calculations analyzed not only position but also orientation of the adsorbed O2 molecules. For the position, cloud of mass densities of O2 molecules by MD simulation showed stacking styles in nano-pores statistically. Number of adsorbed gas was estimated to be 3.00 molecules/unit. For the orientation, a certain adsorbed O2 molecule was stabilized by contribution of the two next O2 molecules as well as four phenyl groups. [Copyright &y& Elsevier]

The ethanol vapor adsorption behavior and the inclusion crystal structure of a 1 D-transformable coordination polymer host were characterized. The adsorption jump was observed during phase transition or two-phase equilibrium with abnormal adsorption enthalpy caused by the nature of ‘mass induced phase transition.’ The included ethanol guests selectively form O—H···O hydrogen bonded pairs inside channels, suggesting selective construction of a specific cluster/aggregate in pores under control of thermodynamic factors and cooperative intermolecular interactions among the guest and channel surface. [ABSTRACT FROM AUTHOR]

The structural determination of saturated adsorbed methane inside a metal-organic cavity by the forcible pressure swing adsorption method (ca. 13 MPa) through a gas-adsorption equilibrium state gives a methane inclusion crystal even at 298 K. The adsorbed methane molecules regularly locate in the pocket-like narrow corners of the necks of the 1-D channel without disorder. The thermal motion of the pseudo-spherical methane molecules seems to be effectively suppressed in its translation mode but allowed rotation. In cooling to 90 K, the crystal structure remained essentially unchanged while the thermal motion decreased, indicating that a lower temperature reduces the rotation of the adsorbed pseudo-spherical methane. The observed crystal structure could also be influenced by a reduction of the vibrational magnitude, and a phase transition from a static disordered structure to an ordered state might occur. The observed crystal state at a higher temperature should have a plastic crystal nature in terms of the randomness of the orientation of incorporated guests. The single-crystal adsorbent is effective for crystallographic observation of the thermal activated guest forced into regular alignment in the crystal lattice, which can be used as a model of the supercritical fluid. [ABSTRACT FROM AUTHOR]

A new series of microporous materials containing infinite chains of mononuclear metal (Cu(II), Zn(II), Ni(II))-pyridine unit bridged by dicarboxylates, copper(II) terephthalate-pyridine, [CuII(OOCC6H4COO)(C5H5N)2(H2O)] · C5H5N · H2O (1), copper(II) terephthalate-4-phenylpyridine, [CuII(OOCC6H4COO)(C11H9N)2(H2O)] · (MeOH)2 (2), zinc(II) fumarate-pyridine, [ZnII(OOCC2H2COO)(C5H5N)3] · C5H5N · (H2O)0.5 (3), zinc(II) terephthalate-pyridine, [ZnII(OOCC6H4COO)(C5H5N)2(H2O)2] · (C5H5N)2 · (H2O)2 (4), nickel(II) fumarate-pyridine, [NiII(OOCC2H2COO)(C5H5N)3] · C5H5N · (H2O)2 (5), and nickel(II) terephthalate-pyridine, [NiII(OOCC6H4COO)(C5H5N)3]6 · (C5H5N)2 · (DMF)6 · (H2O)9 (6), have been prepared. A porous structure, which is formed by stacking and self-assembly of the linear metal(II) dicarboxylates, has been determined by X-ray crystallography. When released with guest solvents, these complexes, except for 5, occlude large amounts of gases such as N2 and Ar. The maximum amount of N2 gas is 0.7–10.7 mol per mole of metal(II) salt, indicating the presence of a large number of micro- and/or mesopores. The magnetic susceptibilities of 1 and 2 obey the Curie–Weiss law over the range of 70–300 K (θ=-1.4 K and θ=+5.5 K, respectively); the obtained Weiss constants (θ) indicate the existence of small antiferromagnetic interactions (1), and ferromagnetic interactions (2). The different magnetic behaviors between 1 and 2 demonstrate that hydrogen bonding between the carboxylate groups and coordinated water molecules plays an important role in determining the bridge geometries and superexchange interaction between the Cu(II) ions through the Cu–O–C–O–H–O–Cu pathways. In contrast to those of the copper(II) complexes, the magnetic susceptibilities of 5 and 6 obey the Curie law.Novel inclusion complexes between host microporous molybdenum(II) dicarboxylates (fumarate (7), terephthalate (8), trans–trans-muconate (9), and pyridine-2,5-dicarboxylate (10)) and guest organic polyethers (poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG)) of various molecular weights have been synthesized. The rate of complex formation depends on the shapes of the micropores and polyethers. The amount of included polyethers increases with their molecular weight, and reaches up to a saturated amount, with the exception that complex 10 does not form complex with bulky PPG. The amount of absorbed argon in the microporous molybdenum(II) dicarboxylates decreases with increase in the amount of include polyethers. The 13C CP/MAS NMR measurement of complex 8 with PEG has demonstrated that PEG chains are included in the capillaries. This is an effective method for synthesizing supramolecular complexes.Three dimensional microporous polymers of Rh fumarate (Rh(f)) (11), Rh terephthalate (Rh(t)) (12), and a novel porphyrin rhodium coordination polymer, [Rh2(H2TCPP)] (H2TCPP=4,4′,4″,4‴-(21H,23H-porohine-5,10,15,20-tetrayl)tetrakis benzoic acid) complexes (13) have exhibited high catalytic activities for hydrogen exchange and hydrogenation of olefins (ethylene, propene, and butene) at 200 K. The turnover frequencies of complexes 11, 12, and 13 for hydrogenation of ethylene at 194 K are much higher than those of other published Rh-containing materials. The microwave spectroscopic analyses of the deuterium isotopic distribution of formed propene-d1 during C3H6–C3D6 reaction over complexes 11 and 12 reveal that the hydrogen exchange reactions take place only inside the nanopores of complexes 11 and 12 without complete scission of C–H bond of olefin molecule. Such a novel bimolecular pathway may play an important role for development of new heterogeneous hydrogenation catalysts. [Copyright &y& Elsevier]

A novel inclusion crystal, {[Rh(II)2(bza)4(pyz)]n · 3n(N2O)} (1), was prepared and characterized by single-crystal X-ray diffraction analysis; linear alignment (N2O)n coherently generates in the channels of host rhodium benzoate pyrazine and there is a high possibility of the existence of an intermediate phase induced by a slight amount of adsorbed N2O inside the crystal even at room temperature. [Copyright &y& Elsevier]

A novel porous solid of ruthenium(II, III) dimer complex, [Ru2(p-O2CC6H4NHCOtBu)4Cl], constructed by intermolecularly linking the hydrogen bonds of NH ⋯ O and NH ⋯ Cl was synthesized and the porous structure was crystallographically determined. The dried crystalline solid shows a high BET surface area determined by measuring the adsorption of nitrogen gas and water vapor. [Copyright &y& Elsevier]

Generally, superelastic behavior cannot be expected in mechanically twinned crystals because there is essentially no strain on the interface that is a driving force for spontaneous shape recovery. However, we found that single crystals of 3,5-difluorobenzoic acid are superelastic organic crystals under mechanical twinning. The unexpected shape recovery can be explained by molecular distortion on the twinning interface, which suggests a new mechanism for superelasticity in molecular materials. [ABSTRACT FROM AUTHOR]

Generally, superelastic behavior cannot be expected in mechanically twinned crystals because there is essentially no strain on the interface that is a driving force for spontaneous shape recovery. However, we found that single crystals of 3,5-difluorobenzoic acid are superelastic organic crystals under mechanical twinning. The unexpected shape recovery can be explained by molecular distortion on the twinning interface, which suggests a new mechanism for superelasticity in molecular materials. [ABSTRACT FROM AUTHOR]

Analyses the chemical reactions of the rubredoxin model complexes with reference to the molecular properties of this complex. Description of the complexes; Information on the formation of the structure of a novel chelating amido(thiolato) complex; Identification of this complex.

A novel molecular crystal membrane [Cu(ii)2(9-AC)4(pyz)]n (9-AC: 9-anthracenecarboxylate, pyz: pyrazine) shows high permselectivity for H2/CO (79.0), H2/CH4 (137), and H2/CO2 (12.1) due to the high rate of H2 permeation (3820 Barrer) while inhibiting the permeation of such a large gaseous particle even in its wider channel than the Lennard-Jones diameter of each gas. [ABSTRACT FROM AUTHOR]

The CO2 adsorption behavior and inclusion structure of a flexible single-crystal host [Cu2(bza)4(pyz)]n were studied under various conditions (203-373 K, o15.4 MPa) and the correlation between changes in gas adsorption behavior and the structures of guest arrangement and host component packing were investigated. [ABSTRACT FROM AUTHOR]

The adsorption behavior of a single-crystal host [Cu2(bza)4(pyz)]n under vapor was studied by adsorption measurements and single-crystal X-ray analyses, demonstrating the sharp replacement of the included guest by mixing the surrounding vapor. [ABSTRACT FROM AUTHOR]

The adsorption behavior of a single-crystal host [Cu2(bza)4(pyz)]nunder vapor was studied by adsorption measurements and single-crystal X-ray analyses, demonstrating the sharp replacement of the included guest by mixing the surrounding vapor. [ABSTRACT FROM AUTHOR]

By the addition of a "leverage" mechanism in a host component of a metal-organic crystal, a channel-switching property was developed in a porous single-crystal adsorbent driven by incorporated guest gas stress, which may provide new single-crystal devices with the active controllability of anisotropic guest diffusivity. [ABSTRACT FROM AUTHOR]

A crystalline solid, [Rh(II)2(bza)4(1,5-nptd)]n (bza and 1,5-nptd=benzoate and 1,5-naphthyridine), was synthesized and characterized by single-crystal X-ray diffraction analysis; the microporous compound demonstrates gas adsorbency with a N2 BET surface area of 291.6 m2 g−1. [Copyright &y& Elsevier]

A novel gas inclusion solid was generated by cooling an empty host crystal of copper(II) benzoate–pyrazine in a carbon dioxide environment and characterized by single-crystal X-ray diffraction analysis. [Copyright &y& Elsevier]

A novel crystalline solid, [Cu(II)2(O2CPh)4(2,5-dmpyz)]n (2,5-dmpyz = 2,5-dimethyl-pyrazine), was synthesized and characterized by single-crystal X-ray diffraction analysis. The compound demonstrates multistep phase transition induced by CO2 adsorption, which readily obeys the Clausius–Clapeyron equation in terms of the set of partial pressures of CO2 and transition temperatures. [Copyright &y& Elsevier]

A novel crystalline solid, [Cu(II)2(O2CPh)4(pyz)]n, was synthesized and characterized by single-crystal X-ray diffraction analysis; the compound demonstrates thermal phase transition that is correlated with CO2 adsorption. [Copyright &y& Elsevier]

A unique mechanical property of superelasticity is observed not only in so-called shape-memory alloys but also in molecular crystals. In contrast, superelasticity can coexist with various attractive functions derived from molecules in the latter. Herein we demonstrate a photoluminescent organosuperelastic crystal of a pure organic compound: 7-amino-4-methylcoumarin. UV light irradiation causes a negligible effect on a stress–strain curve with a typical superelastic hysteresis loop in the crystal. The emission color of yellow-green is visually unchanged during the superelastic deformation because of the twinning nature. Superelasticity coexisting with photoluminescence properties is unprecedented in the conventional SMAs and indicates promising practical applications of molecular crystals as the next generation superelastic materials. [ABSTRACT FROM AUTHOR]

The article presents a study which describes the anistropic permeation properties of gases through a single-crystalline membrane. It states that in the X-ray structural analysis, gas permeability on the channel direction and barrier properties vertical to the direction were observed in the single-crystal membrane, which corresponds to the measured permeability. It concludes the successful permeation of various gases over one-dimensional channels, despite the narrow diameter of sample gases.

Molecular crystals of Pt(II) complexes with metallophilic interactions can provide bright assembly-induced luminescence with colour tunability. However, the brittleness of many of these crystals makes their application in flexible optical materials difficult. Herein, we have achieved the elastic deformation of crystals of polyhalogenated Pt(II) complexes exhibiting bright assembly-induced luminescence. A crystal of [Pt(bpic)(dFppy)] (Hbpic = 5-bromopicolinic acid, HdFppy = 2-(2,4-difluorophenyl)pyridine) and a co-crystal of [Pt(bpic)(dFppy)] and [Pt(bpic)(ppy)] (Hppy = 2-phenylpyridine) were found to exhibit significant elastic deformation due to their highly anisotropic interaction topologies. While the crystal of [Pt(bpic)(dFppy)] exhibited monomer-based ligand-centred 3ππ* emission with an emission quantum yield of 0.40, the co-crystal exhibited bright, triplet metal–metal-to-ligand charge transfer (3MMLCT) emission owing to Pt⋯Pt interactions, thereby achieving a significantly higher emission quantum yield of 0.94. [ABSTRACT FROM AUTHOR]

Herein, we report our results on the synthetic studies of the originally proposed structure of protoaculeine B, isolated from a marine sponge. Starting from tryptophan, two candidates of the suitably protected heterotricyclic subunits were stereoselectively synthesized over 8 and 16 steps, respectively. Furthermore, two diastereomeric heterotricyclic amino acids, finally synthesized, were found to be neuroactive: the (9S*,11S*)‐isomer with natural‐type configuration was hyperactive, whereas diastereomeric (9S*,11R*)‐isomer was hypoactive upon mice intracerebroventricular injection. [ABSTRACT FROM AUTHOR]

Abstract: The first total syntheses of (−)-dysibetaine CPa and the antipode have been achieved using enantioselective solvolysis of meso-cyclic anhydride mediated by quinine derivative as an organocatalyst. The synthesis features a demonstration of an enantiodivergent organic synthesis of both enantiomers of dysibetaine CPa whereby the absolute configurations of natural product were elucidated as (3R,4R). Application of the present methodology to an enantiomerically pure novel GABA analog is also reported. [Copyright &y& Elsevier]

Single crystals showing elastic flexibility have attracted increasing attention as next-generation soft materials. Herein, we successfully developed a series of polyhalogenated platinum(II)–bipyridine complexes showing solvent-of-crystallisation-dependent elastic flexibility. Notably, methanol-solvated crystals were the first examples of flexible crystals showing assembly-induced luminescence arising from the triplet metal–metal-to-ligand charge transfer (3MMLCT) excited state. Furthermore, factors inducing elastic deformability based on the packing structures of the crystals were explored. [ABSTRACT FROM AUTHOR]

Two porous supramolecular isomeric frameworks show unique sorption properties, one with temperature dependent stepwise and hysteretic selective sorption of CO2while the other one shows gas uptake capacity for CO2, N2, H2and CH4at low temperature and selective sorption of CO2over N2around room temperature. [ABSTRACT FROM AUTHOR]

A unique 4-fold interpenetrated (10,3)-bcopper(ii) framework exhibits reversible dehydration and rehydration in a single-crystal-to-single-crystal (SC–SC) process, and the dehydrated material can encapsulate CH3OH molecules, again in a SC–SC fashion, and shows selective adsorption of H2and CO2over N2. [ABSTRACT FROM AUTHOR]

A highly stable copper(ii) microporous framework with cylindrical channels constructed from 1,4-di(1H-imidazol-4-yl)benzene (H2L) and CuCl2·2H2O is composed of Cu(ii)-imidazolate tubes interconnected by the 1,4-phenylene group of L2−, and shows temperature dependent selective gas sorption properties. [ABSTRACT FROM AUTHOR]

Mechanically adaptable molecular crystals have potential applications in flexible smart materials and devices. Here, we report the mechanism of plastic deformation in single crystals of a small organic molecule (N-(4-ethynylphenyl)-3-fluoro-4-(trifluoromethyl)benzamide) that can be repeatedly irreversibly bent and returned to its original shape without concomitant delamination or loss of integrity. Along with the quantification of the crystals' local and bulk mechanical properties (hardness, indentation modulus and Young's modulus), micro-focus synchrotron X-ray diffraction mapping show that upon deformation, molecular layers lined with trifluoromethyl groups cooperatively slip past one another resulting in their impressive plastic malleability. [ABSTRACT FROM AUTHOR]

Ferroelasticity has been reported for several types of molecular crystals, which show mechanical‐stress‐induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light‐emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N‐heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X‐ray diffraction analyses and stress‐strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build‐up of strain. A comparison with single‐crystal structures of related gold‐NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior. [ABSTRACT FROM AUTHOR]

Ferroelasticity has been reported for several types of molecular crystals, which show mechanical‐stress‐induced shape change under twinning and/or spontaneous formation of strain. Aiming to create materials that exhibit both ferroelasticity and light‐emission characteristics, we discovered the first examples of ferroelastic luminescent organometallic crystals. Crystals of arylgold(I)(N‐heterocyclic carbene)(NHC) complexes bend upon exposure to anisotropic mechanical stress. X‐ray diffraction analyses and stress‐strain measurements on these ferroelastic crystals confirmed typical ferroelastic behavior, mechanical twinning, and the spontaneous build‐up of strain. A comparison with single‐crystal structures of related gold‐NHC complexes that do not show ferroelasticity shed light on the structural origins of the ferroelastic behavior. [ABSTRACT FROM AUTHOR]

Mechanical twinning changes atomic, molecular, and crystal orientations along with directions of the anisotropic properties of the crystalline materials while maintaining single crystallinity in each domain. However, such deformability has been less studied in brittle organic crystals despite their remarkable anisotropic functions. Herein we demonstrate a direction‐dependent mechanical twinning that shows superelasticity in one direction and ferroelasticity in two other directions in a single crystal of 1,3‐bis(4‐methoxyphenyl)urea. The crystal can undergo stepwise twinning and ferroelastically forms various shapes with multiple domains oriented in different directions, thereby affording a crystal that shows superelasticity in multiple directions. This adaptability and shape recoverability in a ferroelastic and superelastic single crystal under ambient conditions are of great importance in future applications of organic crystals as mechanical materials, such as in soft robotics. [ABSTRACT FROM AUTHOR]

Mechanical twinning changes atomic, molecular, and crystal orientations along with directions of the anisotropic properties of the crystalline materials while maintaining single crystallinity in each domain. However, such deformability has been less studied in brittle organic crystals despite their remarkable anisotropic functions. Herein we demonstrate a direction‐dependent mechanical twinning that shows superelasticity in one direction and ferroelasticity in two other directions in a single crystal of 1,3‐bis(4‐methoxyphenyl)urea. The crystal can undergo stepwise twinning and ferroelastically forms various shapes with multiple domains oriented in different directions, thereby affording a crystal that shows superelasticity in multiple directions. This adaptability and shape recoverability in a ferroelastic and superelastic single crystal under ambient conditions are of great importance in future applications of organic crystals as mechanical materials, such as in soft robotics. [ABSTRACT FROM AUTHOR]

As altering permanent shapes without loss of material function is of practical importance for material molding, especially for elastic materials, shape‐rememorization ability would enhance the utility of elastic crystalline materials. Since diffusionless plastic deformability can preserve the crystallinity of materials, the interconversion of diffusionless mechanical deformability between superelasticity and ferroelasticity could enable shape rememorization of superelastic single crystals. This study demonstrates the shape rememorization of an organosuperelastic single crystal of 1,4‐dicyanobenzene through time‐reversible interconversion of superelasticity–ferroelasticity relaxation by holding the mechanically twinned crystal without heating. The shape‐rememorization ability of the organosuperelastic crystal indicates the compatibility of superelasticity (antiferroelasticity) and ferroelasticity as well as the intrinsic workability of organic crystalline materials capable of recovering their crystal functions under mild conditions. [ABSTRACT FROM AUTHOR]

As altering permanent shapes without loss of material function is of practical importance for material molding, especially for elastic materials, shape‐rememorization ability would enhance the utility of elastic crystalline materials. Since diffusionless plastic deformability can preserve the crystallinity of materials, the interconversion of diffusionless mechanical deformability between superelasticity and ferroelasticity could enable shape rememorization of superelastic single crystals. This study demonstrates the shape rememorization of an organosuperelastic single crystal of 1,4‐dicyanobenzene through time‐reversible interconversion of superelasticity–ferroelasticity relaxation by holding the mechanically twinned crystal without heating. The shape‐rememorization ability of the organosuperelastic crystal indicates the compatibility of superelasticity (antiferroelasticity) and ferroelasticity as well as the intrinsic workability of organic crystalline materials capable of recovering their crystal functions under mild conditions. [ABSTRACT FROM AUTHOR]

The control of coercive stress in organoferroelasticity is demonstrated in single crystals of trans-1,4-cyclohexanedicarboxylic acid with bulky cyclohexane rings. Flipping difficulty, due to the bulkiness, increased coercive stress, which can improve mechanical damping. Crystals also undergo the spontaneous disappearance of a twinned domain upon unloading before the completion of domain formation. [ABSTRACT FROM AUTHOR]