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The paper reports the relationship between single-walled carbon nanotube (SWNT) doping and capsulate crystal structure in RbxAg1−xI@SWNT composites. The structures of one dimensional (1D) RbI, AgI and RbAg4I5 crystals inside single-walled carbon nanotubes were established by high-resolution transmission electron microscopy (HRTEM) and high-resolution scanning transmission electron microscopy (HAADF HRSTEM), and confirmed by image simulation. Opposite to one-dimensional RbI and AgI, inheriting the structure of bulk analogues, 1D RbAg4I5 forms a new phase within a confined space of the SWNT channel, which differs from the bulk RbAg4I5 structure and can be described by a deformed cubic 1D lattice. X-ray absorption, XPS, optical absorption and Raman spectroscopies were used for comprehensive study of the composites' electronic structures. The study reveals the donor behavior of RbI capsulate and the acceptor behavior of RbAg4I5 and AgI. Quantification of doping levels indicated the prevalence of the effect of the chemical composition of the capsulate on the overall doping efficiency, while a structural effect is mostly prominent in potential distribution on nanotube walls and partial charges on SWNT atoms. [ABSTRACT FROM AUTHOR]

The sole crystal structure generally observed for a chemical compound (actual crystal structure) corresponds to only one of the many minima present in the crystal energy landscape of that compound. A challenging problem of crystallography is to explain why the many other possible crystal structures (in terms of energy and density) present in the landscape (virtual structures) are not observed as polymorphs. In the present paper, with specific reference to semicarbazides of substituted benzoic acids, the concept of actual and virtual structures is extended and it is proven that optimization of a molecule in a different crystal packing of another molecule (interchangeability of molecules and packings) can lead to low minima of the lattice energy and to a high lattice density also in the case of molecules significantly different in shape (para/meta substituted compounds). This suggests that a crystal structure can be viewed as a sort of elastic system that can be deformed to fit molecules of different electronic character and shape. Surprisingly, in many cases, this deformation is accomplished at low cost of energy and density. Our results also suggest that the small number of polymorphs cannot be explained only by inspection of the crystal energy landscape, which would otherwise suggest many, but also, and perhaps mostly, by the analysis of the initial steps of crystal formation even before nucleation, when many different molecular clusters corresponding to different packings are in competition with each other. [ABSTRACT FROM AUTHOR]

This work deals with the synthesis and crystal structure study of new bismuth oxo-arsenates and their homologous oxo-phosphates: Bi6ZnO7(AsO4)2vs. Bi6ZnO7(PO4)2 and Bi3.667Cd3O4(AsO4)3vs. Bi3Cd4O4(PO4)3. Their crystal structures were solved using single crystal X-ray diffraction. These are two other examples of crystal structures built on ribbon-like polycations formed of the linkage of oxo-centered O(Bi,M)4 tetrahedra sharing edges and surrounded by isolated XO4 groups (X = As or P), where the O(Bi,M)4 units are derived from the fluorite topology structure. Dealing with Bi6ZnO7(PO4), its acentric space group was confirmed by preliminary second harmonic generation (SHG). The P/As substitution led to a centrosymmetric space group due to local reorientation of oxo-anions. This is strongly related to steric effects between AsO4 (d As–O = 1.6–1.7 Å) and PO4 (d P–O = 1.4–1.5 Å). Concerning Bi3.667Cd3O4(AsO4)3 and Bi3Cd4O4(PO4)3, they show a second example of the reorientation of the XO4 groups depending of the X chemical nature. Finally, we present an original topology of oxo-centered units obtained with Bi5KO5(AsO4). The photoluminescence properties of Bi5KO5(AsO4) and Bi6ZnO7(AsO4)2 were also investigated. The first one emits at room temperature in the reddish-orange range (single band peak at 615 nm assigned to the Bi3+: 3P1→1S0 transition) whereas the second exhibits a weak emission in the green range (peak at 530 nm). Its intriguing temperature dependence is discussed in the paper. [ABSTRACT FROM AUTHOR]

Control of crystal structures is essential to tailor the properties of inorganic polymorphic materials for specific applications. For conventional solid transformations, re-arrangement of structural units is usually done at high temperatures and/or pressures (Dalton Trans., 2012, 41, 11927–11948). Such a case could become relatively mild when using solution chemistries, as there is unique reaction medium that allows for formation or transformation to the desired crystal phase through atomic-level cation–anionic interaction, providing potential opportunities for crystal structure control. In this paper, research progress of solution chemistry is highlighted in crystal phase-controlled synthesis of inorganic nano-compounds such as simple metal oxides, chalcogenides, halides, oxysalts etc. After briefly introducing crystal phase diversity and phase-dependent properties of inorganic nano-compounds, the discussion focuses on the critical driven items in the solution reactions such as precursor, pH value, solvents, ions, and water, as well as kinetic factors. Eventually, based on the current research status of the crystal phase-controlled synthesis of inorganic nano-compounds, some perspectives are provided on the challenges and opportunities in this emerging research field. [ABSTRACT FROM AUTHOR]

The synthesis, single-crystal structure characterization and detailed magnetic study of a homometallic hexanuclear CuII cluster [Cu6(μ3-OH)2(ppk)6(H2O)2(NO3)4] (1) and a three-dimensional (3D) compound [{MnCu2(dpkO2H)2(dpkO2)N3}·(NO3)·H2O]n (2) (ppk = phenyl-2-pyridyl ketoxime; dpk = di-2-pyridyl ketone) consisting of heterometallic MnII–CuII hexanuclear cores as secondary building units are reported in this paper. In compound 1, two symmetry-related Cu3 triangles consisting of a hydroxido-bridged trinuclear unit, [Cu3(μ3-OH)(ppk)3(H2O)(NO3)]+, are assembled through nitrate bridging giving rise to the homometallic Cu6 cluster. Compound 2 contains heterometallic {MnII2CuII4} cores, which are further connected to each other through an azido bridging ligand in all the crystallographic directions, resulting in a 3D metal–organic framework. Construction of such a heterometallic 3D framework from {MnII2CuII4} units is until now, unknown. Magnetic studies of both 1 and 2 were performed in detail and both compounds show dominant antiferromagnetic interaction in the respective clusters. Compound 1 reveals significant spin frustration and anti-symmetric exchange interaction in the trinuclear cores, with a significantly high value of Jav (−655 cm−1). Furthermore, compound 2 exhibits a dominant antiferromagnetic interaction, which is also supported by an extensive magneto-structural correlation which considers the different magnetic pathways. [ABSTRACT FROM AUTHOR]

The photodimerization of 9-tert-butyl-anthracene ester in molecular crystal nanorods can cause expansions of up to 15%. This expansion results from the formation of a metastable crystalline intermediate, the solid-state reacted dimer (SSRD). In this paper, a combination of powder X-ray diffraction, solid-state nuclear magnetic resonance, and computational modeling is used to determine the crystal structure of the SSRD intermediate. An ensemble of six possible structures is obtained, which differ only in small packing details that lead to different crystal space groups. The structure with the best overall agreement with the experimental data belongs to the Pccn space group and, like the other members of the ensemble, retains a packing motif close to that of the monomer crystal. This crystal structure allows us to conclude that the SSRD crystal density is slightly greater than that of the monomer crystal and that gross changes in the volume or unit cell parameters of the SSRD are not responsible for the photoinduced expansion. [ABSTRACT FROM AUTHOR]

Since their first appearance in the chemistry scene thirty years ago, resorcinarene-based cavitands have been recognized to be a highly versatile class of compounds. Endowed with a rigid cavity of molecular dimensions, which can be decorated at the upper and lower rims with a variety of functional groups, they are efficient molecular receptors for chemical sensing, as well as tunable building blocks in the formation of covalent and supramolecular architectures. In this paper, we highlight and discuss “classic” and recent results concerning their chemistry, applications and crystal structure. [ABSTRACT FROM AUTHOR]

In this review, aspects of the syntheses, structures and magnetic properties of giant 3d and 3d/4f paramagnetic metal clusters in moderate oxidation states are discussed. The term “giant clusters” is used herein to denote metal clusters with nuclearity of 30 or greater. Many synthetic strategies towards such species have been developed and are discussed in this paper. Attempts are made to categorize some of the most successful methods to giant clusters, but it will be pointed out that the characteristics of the crystal structures of such compounds including nuclearity, shape, architecture, etc. are unpredictable depending on the specific structural features of the included organic ligands, reaction conditions and other factors. The majority of the described compounds in this review are of special interest not only for their fascinating nanosized structures but also because they sometimes display interesting magnetic phenomena, such as ferromagnetic exchange interactions, large ground state spin values, single-molecule magnetism behaviour or impressively large magnetocaloric effects. In addition, they often possess the properties of both the quantum and the classical world, and thus their systematic study offers the potential for the discovery of new physical phenomena, as well as a better understanding of the existing ones. The research field of giant clusters is under continuous evolution and their intriguing structural characteristics and magnetism properties that attract the interest of synthetic Inorganic Chemists promise a brilliant future for this class of compounds. [ABSTRACT FROM AUTHOR]

This paper describes the crystal growth, structure and properties of a new semi-organic hybrid crystal with an accurate molecular formula of ZnMnCl4(TPPO)4 by a guest–host combination of ZnCl2(TPPO)2 and MnCl2(TPPO)2 for the first time and its formation is bidirectional. It crystallizes in the acentric space group Fdd2. The 3D framework of the crystal structure is formed by triphenylphosphine oxide (TPPO), linked with a mixture of zinc(ii) chloride and manganese(ii) chloride. A mixed occupancy of zinc and manganese atoms was designed to form a noncentrosymmetric coordination compound, which exhibits relatively strong second-order nonlinear properties. The powder of this crystal shows a phase-matchable SHG effect that is twice that of KH2PO4 (KDP). The crystal has a broad optical transmission range, relatively good stability and a wide band gap. It is also magnetic and luminescent. The properties of this new crystal make it a potential candidate for improved or even novel devices. [ABSTRACT FROM AUTHOR]

The effects of crystallization on the formation of geochemical, biological, and synthetic materials have been motivating decades of research into crystal nucleation and growth processes. The development of crystal growth theories and models can deepen the understanding of physicochemical interactions during the crystal growth process, which facilitates the designing of crystallization approaches in material production. The chemical bonding theory of single crystal growth emphasizes the dominant role of dynamic chemical bonding mechanisms at the growing interfaces. In this paper, we highlight the chemical bonding theory of single crystal growth from the chemical reaction viewpoint, by focusing on the atomic level of the growing interface between the liquid and crystal phases. Using ZnO, CeO2, MnO2 and Y3Al5O12 as examples, we review some typical applications of the chemical bonding theory of single crystal growth in calculating crystal habits, evaluating crystal properties, and guiding practical single crystal growth. Microscopically speaking, the essence of crystal growth and design is to create ideal chemical bonding architectures at both the crystal surface and the growing interface via both thermodynamic and kinetic strategies. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate framework-L (ZIF-L) is an emerging ZIF material possessing a unique two-dimensional layered crystal structure and a leaf-like crystal morphology. This paper reports a novel approach towards the incorporation of single-walled aluminosilicate nanotubes (AlSiNTs) into the interlayer of ZIF-L for the synthesis of AlSiNT@ZIF-L nanocomposites. The interlayer in ZIF-L is formed by hydrogen bonding between adjacent imidazoles. The resulting nanocomposites were subjected to a number of solid-state characterization techniques (SEM, TEM, powder XRD, EDS, TGA, nitrogen physisorption, and FT-IR) to elucidate the conformation of their microstructure. It was found that the AlSiNT@ZIF-L composite possesses an average crystal size considerably smaller than that of pure ZIF-L (1.1 μm for AlSiNT@ZIF-L and 7.8 μm for pure ZIF-L). Interestingly, ZIF-L and AlSiNTs are both microporous; however, the mesoporosity was achieved through the incorporation of AlSiNTs into ZIF-L crystals. A control experiment related to the synthesis of AlSiNT@ZIF-8 composites was performed to gain insight into the assembly pathway towards the formation of AlSiNT@ZIF-L crystals. Failure in the formation of AlSiNT@ZIF-8 supports the supposition that the assembly pathway involves the incorporation of AlSiNTs into the interlayer of ZIF-L, thereby facilitating the nucleation of ZIF-L crystals. [ABSTRACT FROM AUTHOR]

In this paper, hierarchical MnCo2O4@MnO2 core–shell nanowire arrays (MnCo2O4@MnO2 NWAs) with mesoporous and large surface area are synthesized on 3D nickel foam via a facile, two-step hydrothermal approach without any adscititious surfactant and binder. The electrode architecture takes advantage of the synergistic effects contributed from both the porous MnCo2O4 nanowire core and the MnO2 shell layer. The fabricated MnCo2O4@MnO2 NWA electrode for supercapacitors in aqueous electrolyte exhibits a significantly enhanced specific capacitance (858 F g−1 at 1 A g−1), high energy density (36.0 Wh kg−1 at 252 W kg−1) and long-life cycling stability (retaining 88% of the initial capacitance after 5000 cycles). Then, a symmetrical supercapacitor is fabricated by assembling two MnCo2O4@MnO2 NWA-based electrodes, which shows a high specific capacitance of 678 F g−1 at 1 A g−1 and a high energy density of 135.6 Wh kg−1 at 513 W kg−1. Thereby, the hierarchical core–shell MnCo2O4@MnO2 NWAs are very promising as next generation high-performance long-life cycling supercapacitors. [ABSTRACT FROM AUTHOR]

Controllable synthesis of materials with designed structures is a long-term dream of scientists and engineers. The challenges faced by dreamers are the complexity of material formation and the diversity of material structures. One way to discover this complexity is to simplify the reaction system. Electrochemical reduction is one of the simple reaction systems in which electrons are used as the reductant to avoid the complexity of chemical effects. We design a two-cell electrochemical reactor. The cathode and the anode are placed in different cells connected by a salt bridge. Electrons are introduced into the cell containing silver ions. With this approach, silver particles are synthesized on the cathode. The reduction rate of silver ions is regulated by varying the current density over two orders of magnitude. At various current densities, silver particles with different morphologies are synthesized. The dependence of silver morphology on current density is ascribed to the influence of current density on the nucleation and growth of silver particles, which is confirmed by subsequent experiments. The results in this paper show that the electron is a simple and green reductant and the current density is an effective tool for regulating reaction rates to shape materials. [ABSTRACT FROM AUTHOR]

Zeolitic imidazolate frameworks (ZIFs) have attracted considerable attention for many potential applications because they have a unique porous structure and excellent thermal and chemical stabilities. In recent years, significant efforts have been made to develop different methods for the controllable synthesis of ZIFs with desirable crystal structure and morphologies, and for decreasing the excessive amounts of organic ligands and solvents used in the synthesis process to reduce the costs and environmental impacts. This paper highlights the strategies recently reported, including the controllable synthesis of ZIFs with desirable morphologies and pore structure using a surfactant and a template in aqueous solution, the synthesis of ZIF particles and nanocrystals in base solution, and the dry gel and mechanochemical syntheses of ZIFs with minimal solvent usage. [ABSTRACT FROM AUTHOR]

Cylindrical SrTiO3 single crystals with diameters and lengths exceeding one inch were grown from non-stoichiometric melts below 1800 °C using the high temperature top-seeded solution growth (TSSG) method. Despite the large crystal diameter the quality has been improved compared to Verneuil grown crystals. Typical etch pit density (EPD) values are in the range between 2 × 104 and 2 × 105 cm−2 for bulk crystals pulled in the ＜100＞ direction and using seeds with EPD values of 5 × 105 cm−2. So far pulling SrTiO3 crystals from the melt suffers from growth instabilities like foot formation and subsequent spiraling. To avoid them an effective heat transport via the crystal is indispensable. Especially at elevated temperatures it requires a high optical transparency in the infrared region. In this paper we report the correlation between oxygen partial pressure, composition, IR-transmittance and coloration of the crystals. The growth at a sufficiently high oxygen partial pressure leads to an increase in the optical transparency of the crystals and can thereby suppress foot or spiral formation. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesized a new garnet structure compound Ca3Hf2SiAl2O12 and a series of Ce3+-doped Ca3Hf2SiAl2O12: xCe3+ phosphors. The crystal structure and luminescence properties of the Ca3Hf2SiAl2O12: xCe3+ are investigated in detail. Transmission electron microscopy analysis and XRD Rietveld refinement shows that Ca3Hf2SiAl2O12 is body-centered cubic and belongs to Ia3̅d (230) space-group with a = 12.3666 Å. Ca3Hf2SiAl2O12: xCe3+ has broad excitation bands at 330 and 400 nm attributed to the characteristic Ce3+ 5d–4f transition and can produce cyan emission under 400 nm UV light excitation. The emission intensity of CHSA: 1%Ce3+ phosphor can reach 68.9% of YAG: Ce3+ (commercial) and 72.1% of Ca8Mg(SiO4)4Cl2: Eu2+ (commercial). The average decay lifetime of Ca3Hf2SiAl2O12: 1%Ce3+ is 48.91 ns, which is consistent with the nanosecond peculiarity of Ce3+. In the process of increasing the temperature from 25 °C to 250 °C, the integrated emission intensity of Ca3Hf2SiAl2O12: 0.5%Ce3+ only decreases to 57.8% (250 °C) and shows nice thermal stability compared with commercial YAG: Ce3+(P46-Y3). Furthermore, Ca3Hf2SiAl2O12: 0.5%Ce3+ exhibits outstanding quantum efficiency (74.7%). It reveals that Ca3Hf2SiAl2O12: xCe3+ possesses remarkable optical properties and can be utilized in UV-LEDs. [ABSTRACT FROM AUTHOR]

A novel biotemplating method for fabricating gold nanoshells (AuNSs) through direct co-incubation of AuCl3 solution and an adenovirus shuttle vector-GFP (Adv) template in water, followed by the reduction of the mixture using fresh NaBH4, has been investigated in this paper. For comparison, different adenovirus-templated gold nanoshells (Adv-AuNSs) were prepared by modifying Adv with chitosan or changing the ionic conditions of the reaction system. The morphology and structure of the prepared AuNSs were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). The result indicated that Adv-AuNSs prepared by co-incubation of naked Adv and 7.5 mM AuCl3 solution had a uniform structure of approximately 120 nm diameter and face-centered cubic (fcc) crystal structure in the XRD pattern. A study of the biocompatibility of the prepared Adv-AuNSs demonstrated that there was no significant cytotoxicity. In addition, the photothermal therapy efficacy of the Adv-AuNSs on tumor cells was investigated in detail, revealing that all tumor cells could be killed when the power of near-infrared light irradiation was 4 W cm−2. Therefore, the prepared Adv-AuNSs will have very promising applications in the photothermal therapy of tumors. [ABSTRACT FROM AUTHOR]

The focus of this paper is on the analysis of the structural and electronic order–disorder effects at long, medium and short ranges of titanium dioxide (TiO2) nanoparticles synthesized by the sol–gel process followed by the microwave-assisted solvothermal (MAS) method at low temperatures and short reaction times. X-ray diffraction (XRD), Rietveld refinement, micro-Raman (MR) spectroscopy, transmission electron microscopy (TEM) and X-ray spectroscopy (EDX) were used to characterize the TiO2 nanoparticles. Optical properties were investigated by ultraviolet-visible (UV-vis) and photoluminescence (PL) measurements performed at room temperature. XRD and Rietveld refinement confirmed the presence of the anatase and brookite phases; nonetheless anatase is the major phase. The X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of only Ti4+ but the nonstoichiometry revealed that TiO2 NPs contain defects assigned to oxygen vacancies that lead to structural and electronic order–disorder effects observed by band gap narrowing and PL wide band emission. These intermediary energy levels (shallow and deep levels) created within the band gap act as acceptors/donors of electrons and recombination centers. The oxygen vacancies (VOx, VOṖ and VOṖṖ) responsible by degree of structural order–disorder are related to distortions (tilts) on the [TiO6] octahedron and changes in the bond lengths and bond angles between oxygen and titanium atoms that gave rise to new species of cluster makers such as [TiO6]′, [TiO5·VOx], [TiO5·VOṖ] and [TiO5·VOṖṖ]. This structural transformation is consistent with a redistribution of electron density from highly ordered [TiO6]x clusters which form distorted [TiO6]′ as well as complex [TiO5·VOx], [TiO5·VOṖ] and [TiO5·VOṖṖ] clusters assigned to oxygen vacancies which were understood as displacements in the oxygen atoms’ position in the bond lengths (Ti–O). [ABSTRACT FROM AUTHOR]

Porous cobalt oxide (Co3O4) nanorod (50-100 nm) and nanosheet-like (70-100 nm) particles were synthesized by a facile hydrothermal method at 150 °C for 2-5 h and 12-24 h, respectively, using aqueousbased precursors like cobalt nitrate, urea and water in the absence of any templating agents followed by their calcination at 300 °C. Morphology and textural properties were tuned by changing the synthesis time at 150 °C. A 3D architecture of Co3O4 was formed by the self-assembly of nanostructured (nanorod and nanosheet) particles. The BET surface area, pore volume and pore diameter of the sample prepared at 150 °C for 5 h were 112 m² g-1, 0.5 cm³ g-1 and 7.4 nm, respectively, and it exhibited the highest catalytic performance with a rate constant of 56.8 × 10-3 min-1 for the degradation of Chicago Sky Blue 6B, a carcinogenic azo dye used in the textile, paper and food industries. Rod-like particles with a mesoporous structure rendered a better catalytic efficiency than sheet-like particles having both microporous and mesoporous structures. An interrelationship amongst the morphology, textural properties and the catalytic efficiency of Co3O4 was established. [ABSTRACT FROM AUTHOR]

Scheelite related alkali-metal rare-earth double molybdate compounds with a general formula of ALn-(MoO4)2 can find wide application as red phosphors. The crystal chemistry and luminescence properties of red-emitting CsGd1-xEux(MoO4)2 solid-solution phosphors have been evaluated in the present paper. A detailed analysis of the structural properties indicates the formation of isostructural scheelite-type CsGd1-xEux(MoO4)2 solid-solutions over the composition range of 0 = x = 1. The photoluminescence emission (PL) and excitation (PLE) spectra, and the decay curves were measured for this series of compounds. The critical doping concentration of Eu3+ is determined to be x = 0.6 in order to realize the maximum emission intensity. The emission spectra of the as-obtained CsGd(1-x)Eux(MoO4)2 phosphors show narrow high intensity red lines at 592 and 615 nm upon excitation at 394 or 465 nm, revealing great potential for applications in white light-emitting diode devices. [ABSTRACT FROM AUTHOR]

Compounds with isolated anionic groups often exhibit special linear and nonlinear optical properties and possess potential applications such as birefringence, second harmonic generation and stimulated Raman scattering crystals. In this paper, two new alkali and alkaline earth mixed-metal borates, Li3KB4O8 and LiNa2Sr8B12O24F6Cl, with isolated (B12O24)12- anionic groups have been successfully synthesized by spontaneous crystallization. Their structures were determined by single crystal X-ray diffraction and they both crystallize in the same space group, R3. More interestingly, further structure comparison shows that the discovered anhydrous borates with the (B12O24)12- groups also crystallize in the same space group R3, which is related with the local symmetry of the (B12O24)12- groups. These structural features suggest that the crystal structures of the family of compounds depend more on their anionic groups. In addition, the property characterizations of the two new borates were investigated by TG-DSC, IR and UV-vis-NIR diffuse reflectance. [ABSTRACT FROM AUTHOR]

This paper presents the syntheses and crystal structures of four copper(ii)–uranyl(vi) compounds [{CuIILOEt–en}2·{(UVIO2)(NO3)2(H2O)2}] (1), [CuII(MeCN)LOEt–pn(UVIO2)(NO3)2] (2), [(UVIO2)2(μ-H2O)2(NO3)4]·4[CuIILOEt–py(H2O)]·2MeCN (3) and {[CuIILOMe–en(UVIO2)(NO3)]2[(UVIO2)2(μ-HO)2(NO3)4]}n (4), where H2LOEt–en, H2LOEt–pn, H2LOEt–py and H2LOMe–en are 3-ethoxysalicylaldehyde-diamine (H2LOEt) or 3-methoxysalicylaldehyde-diamine (H2LOMe) ligands in which the diamine functionality are ethylenediamine, 1,3-diaminopropane, 2,3-diaminopyridine and ethylenediamine, respectively. Compound 1 is a [1 × 2 + 1 × 1] trinuclear cocrystal containing two mononuclear [CuIILOEt–en] and one mononuclear [(UVIO2)(NO3)2(H2O)2] moiety; two coordinated water molecules interact with two O4 compartments by forming hydrogen bonds. Compound 2 is a dinuclear system in which two phenoxo oxygen atoms coordinate with the uranium(vi) centre. Compound 3 is a [2 × 1 + 1 × 4] hexanuclear cocrystal of four mononuclear [CuIILOEt–py(H2O)] units and one dinuclear [(UVIO2)2(μ-H2O)2(NO3)4] moiety; O–H…O and C–H…O interactions interlink the five units here. In 4, there are two dinuclear [CuIILOMe–en(UVIO2)(NO3)]+ cations and one dinuclear [(UVIO2)2(μ-HO)2(NO3)4]2− anion, which are self-assembled to generate a one-dimensional topology. Interesting structural aspects including the weak interaction directed self-assemblies and most importantly, the competition between hydrogen bond and coordinate bond formation and the influence of the reactant ratio in governing that competition are discussed. The diffuse reflectance or solution transmission spectra (for the d–d band) of 1–4 and the corresponding mononuclear copper(ii) precursors are also described. [ABSTRACT FROM AUTHOR]

The crystal structure of Mosher's salt 3, prepared from (R)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid [(R)-MTPA, (R)-1] and (R)-1-phenylethylamine [(R)-PEA, (R)-2], was determined using X-ray crystallography. In crystalline salt 3, the bifurcated hydrogen bond (i.e., the methoxy-group-assisted salt bridge) and the aromatic C–H…π interaction formed the closest ion pair of the MTPA anion and PEA cation. The crystal packing of salt 3 was also determined. The conformations of the crystalline (Racid)-MTPA esters were then statistically examined using the Cambridge Structural Database (CSD). For secondary alcohols, ca. 65% of the dihedral angles between the ester carbonyl groups and the trifluoromethyl groups ranged between −30° and 0°. The other conformational properties associated with the trifluoromethyl, methoxy, and phenyl groups were examined in detail. The conformation of the MTPA ester prepared from the tertiary alcohol is also discussed in this paper. [ABSTRACT FROM AUTHOR]

Constructing novel materials with a hierarchical structure has become an increasingly hot research topic, because the hierarchical structures have wide potential applications in the fields of bionics, electronics, photocatalysis, solar cells, and lithium ion batteries. In this paper, we report on the fabrication of rhombohedral corundum-type indium oxide (rh-In2O3) hierarchical rod-aggregates by annealing oxyhydroxide (InOOH) counterparts prepared through a simple solvothermal route without surfactant. The formation mechanism of the InOOH hierarchical structures is suggested. The rh-In2O3 hierarchical crystals were tested in the role of sensing ammonia gas, and were found to show an excellent gas-sensitivity to NH3 as compared to the cubic bixbyite-type indium oxide (c-In2O3) analogues. [ABSTRACT FROM AUTHOR]

This paper reports, for the first time, the nonlinear optical property of β-HgBrCl, which was synthesized by a reaction of Hg2Cl2 and Br2 in EtOH. This reaction also gave α-HgBrCl. And the single crystal structures of both α- and β-HgBrCl are presented and compared. β-HgBrCl shows phase-matchable powder second harmonic generation (SHG) effect of about 2 times that of KH2PO4 (KDP). Its absorption edge in UV-vis spectrum locates at 366 nm, implying a wide band gap and therefore higher laser damage threshold. It also exhibits a relatively wide transparent window (from 0.4 to 20 μm) and relatively good thermal stability. [ABSTRACT FROM AUTHOR]

Gold phosphide (Au2P3) is known as a crystalline metastable phase at the macroscale. In this paper, the formation of Au2P3 nanostructures is investigated. Here, white phosphorus (P4) is used as a soluble phosphorus donor and reacted on 16 nm gold nanoparticles, in a strategy similar to the one previously used for the production of various metal phosphide nanoparticles including Ni2P, Pd5P4, PdP2, Cu3P and InP. Moderate temperature (250 °C for up to 6 h) gives a reaction limited to the surface of the nanoparticles, while the unreacted P4 stays in solution. This surface modification is then optimized by reducing the stoichiometry of P4 to Au : P = 10 : 1 and lowering the temperature to 110 °C. Interestingly, this surface modification shields the plasmon band against ligand exchange with thiols, providing more robust nanoparticles. The reaction is then conducted under harsh conditions (320 °C for 3 h) to produce crystalline Au2P3. This triggered the aggregation of the starting nanoparticles into larger nanostructures such as nanowires. Moreover, the formation of composite Au2P3–Au nanostructures is observed, where the gold phosphide domains are systematically larger than the unreacted gold nanoparticles. This suggests that gold is particularly reluctant to form gold phosphide, which relates to the metastable character of this phase. [ABSTRACT FROM AUTHOR]

A survey of the Cambridge Crystallographic Database reveals that there are 17 1H-indazoles forming dimers (7), trimers (4) and catemers or chains (6). Amongst the catemers there is one centrosymmetric compound and five non-centrosymmetric ones that crystallize in chiral helices, either M or P, including indazole itself, whose structure has been determined anew. An explanation will be provided for how an achiral molecule crystallizes in a chiral space group. The second part of the paper is devoted to the use of Vibrational Circular Dichroism (VCD) for determining the absolute configuration of a crystal of indazole. This previously needs the complete assignment of its IR and Raman spectra in solution and in the solid-state based on B3LYP/6-31G(d) calculations of indazole dimers and trimers, which are already chiral. [ABSTRACT FROM AUTHOR]

This paper details the synthesis, characterisation including crystal structure, and testing for antimicrobial efficacy of two compounds: a zinc centred bis(N-allylsalicylideneiminato)-zinc (ZSB) and its known copper analogue, bis(N-allylsalicylideneiminato)-copper (CSB). Differences in antimicrobial efficacy of the two compounds were observed, suggesting possible mechanisms for antimicrobial activity. The ZSB system was plasma deposited under various pulse conditions onto non-woven fabric, and the antimicrobial efficacy of the resultant film measured for Staphylococcus aureus and Pseudomonas aeruginosa. These results suggest the potential utility of this compound as an effective antimicrobial thin film, and confirm the critical role the ligands play in effecting antimicrobial activity. [ABSTRACT FROM AUTHOR]

In this paper, hexagonal bipyramids and X- and polycrystal-shaped twins of cholic acid are acquired through the acidic hydrolysis of its ester hydrogel. The growth mechanism is proposed on the basis of the hydrophobic swallowtail-shaped tetramers found in the single-crystal structure. [ABSTRACT FROM AUTHOR]

In this paper we describe several new pieces of software that allow the Cambridge Structural Database (CSD) to be searched for solvated and unsolvated crystal structures. One program finds all pairs of solvated and unsolvated crystal structures of the same chemical compound for a given solvent; another program finds all crystal structures that were grown from a particular solvent. In addition, an algorithm was implemented to determine the stereochemistry of a crystal structure from its 3-D atomic coordinates. Results for water as the solvent molecule are presented. It is found that about 25% of all crystal structures grown from water form hydrates. If a chemical compound is soluble in water, it seems almost impossible to predict if it will form a hydrate or not, although presence of both donors and acceptors in the host compound appears to be required. Chiral molecules produce significantly more hydrates, presumably including water to achieve close packing in spite of the lack of inversion centres. [ABSTRACT FROM AUTHOR]

This paper reports the growth and spectral properties of the Cr3+:CaMgSi2O6 (Cr3+:CMS) crystal. The Cr3+:CMS crystal was grown by the Czochralski method. Investigation of its spectral properties shows that the Cr3+:CMS crystal has broad, strong absorption and emission cross-sections. It has two broad absorption bands which center at 460 nm and 652 nm. The emission cross-section σe at 986.1 nm is 14.39 × 10-20 cm2 at 300 K. The emission FWHM is up to 212 nm. Therefore, the Cr3+:CMS crystal can be considered as a potential tunable and ultrashort pulse laser crystal. [ABSTRACT FROM AUTHOR]

In this paper we report a novel heterocluster H5[Na17MnII 43-(PO4)36] (1), which is the first example of a crystal incorporating manganese clusters and hexametallic sodium wheels simultaneously, and these building blocks are connected to each other through phosphate groups to form a three-dimensional network. Its complicated but aesthetically pleasing architecture exhibits a perfect combination of hexamers. [ABSTRACT FROM AUTHOR]