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Through tuning the conformations of N-donor ligands and the coordinative preferences of metal ions, three new metal–organic frameworks with different dimensionalities, namely, {[Co(L1)(bpp)(H2O)]·0.63H2O}n(1), [Ni(L1)(bpp)(H2O)(CH3OH)]n(2) and {Co2(L1)2(bpe)2(H2O)2}·(H2O)(CH3CN)}n(3) (H2L1 = 1,2-bis(4-carboxy-phenoxy)ethane, bpp = 1,3–bis(4-pyridyl)propane and bpe = 1,2–bis(4-pyridyl)ethene), have been synthesized and structurally characterized. Compound 1exhibits a 2D → 2D parallel interpenetrating motif containing two kinds of double helixes. Polymer 2displays 2D → 3D interpenetrating framework. Compound 3is composed of 3D unusual self-interpenetrating net with (4,6)-connected (54·68)(56·65·72·82) topology. This work evidently indicates that the effect of secondary ligands and geometric preferences of metal centers are critical in construction of polymeric arrangement. In addition, the stabilities of these compounds and the magnetic behaviour of 3are discussed. [ABSTRACT FROM AUTHOR]

Magnéli phase titanium oxide (TinO2n−1, 4 ≤ n ≤ 10) has wide application prospects in energy storage, catalysis and other fields. During the preparation of the TinO2n−1 phase from TiO2 by the carbothermal reduction reaction (CRR), the coexistence of multiple phases caused by the change in the reduction degree is the theoretical and practical basis for obtaining TiO2/TinO2n−1 composite materials. In this work, the H2Ti3O7 nanofiber has been employed as a precursor for the following CRR process. The X-ray diffraction (XRD), Raman spectroscopy, Thermogravimetric (TG) and Differential Scanning Calorimetry (DSC) analysis results confirmed the phase transformation process of H2Ti3O7 → TiO2(B) → anatase → rutile → TinO2n−1. Comprehensive transmission electron microscopy (TEM) characterization was carried out to investigate the phase composition and interface structures of the products calcinated at different temperatures. TiO2/Ti5O9 and λ-Ti3O5/γ-Ti3O5 interfaces with specific orientation relationships have been observed. In addition, the phase transition mechanism has also been revealed based on the structural analysis results. By carefully considering the crystal structure and symmetry of the parent and new phase, the initial lattice strain matrix based on the two observed interfaces has been established accordingly. The crystallographic features of the two types of interfaces have been calculated based on modified invariant line theory, which has confirmed the consistency of the experimental observation and calculated results. The research in this paper can further expand the applicability of the three-dimensional invariant line theory in low symmetry crystal materials. [ABSTRACT FROM AUTHOR]

A bibliographic and literature-based analysis of the impact of the Cambridge Structural Database (CSD) and the papers associated with crystal structures in the CSD has been undertaken. The analysis shows the broad impact of the CSD in the chemical sciences and also highlights how areas where the CSD has impact have changed over time. In addition, we note the changing nature of crystallography as a science, observing how crystal structures are now impactful. A brief illustration of some more unusual contributions to the CSD and publications using the CSD is also presented. [ABSTRACT FROM AUTHOR]

In this paper, a series of mononuclear/binuclear Cu(i) complexes, [CuI(dpq)(PPh3)2](CF3SO3)·CH3OH (1a), [CuI(dppz)(PPh3)2](CF3SO3)·CH3OH (1b), [CuI2(dpq)2(dppm)2](CF3SO3)2 (2a), [CuI2(dppz)2(dppm)2](CF3SO3)2 (2b), [CuI(dpq)(dppp)](CF3SO3)·CH3OH (3a), [CuI(dppz)(dppp)](CF3SO3)·CH3OH (3b), [CuI(dpq)(POP)](CF3SO3)·CH3OH (4a), [CuI(dppz)(POP)](CF3SO3)·CH3OH (4b), [CuI(dpq)(xantphos)](CF3SO3) (5a), and [CuI(dppz)(xantphos)](CF3SO3) (5b) {dppm = 1,1-bis(diphenylphosphino)methane; dppp = 1,3-bis(diphenylphosphino)propane; POP = bis[2-(diphenylphosphino)phenyl]ether; xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene; dpq = pyrazino[2,3-f][1,10]-phenanthroline; dppz = dipyrido[3,2-a: 2′,3′-c]phenazine} have been synthesized and characterized by using IR, NMR, elemental analysis, terahertz (THz) time-domain absorption spectroscopy, UV-vis and fluorescence spectroscopy methods as well as single crystal X-ray diffraction analysis. The single crystal X-ray diffraction results indicated that the immediate geometry around each central Cu(i) in the above complexes is a distorted tetrahedron with the central metal atom being coordinated by the two phosphorus atoms of the phosphine ligands and two nitrogen atoms of the bidentate N-containing heterocyclic ligand moieties. It is found that complexes 1a–5a and 5b show photoluminescence in the solid state at room temperature with the highest quantum yield up to 0.5519, and the increased conjugation in the diimine ligands leads to emission reduction along with a red-shift in the emission maxima. Detailed photo-physical studies and density functional theory calculations (DFT) of these complexes have revealed that their lowest energy absorptions and emissions are ascribed to metal-to-ligand charge transfer (MLCT) excited states. The above results indicate that conjugation effects of N-heteroaromatic ligands play a significant role in the emission properties of mononuclear/binuclear Cu(i) complexes. For the first time, terahertz time-domain spectroscopy is applied for qualitatively understanding the photophysical properties of complexes, revealing that terahertz time-domain spectra are sensitive to the weak interaction between the ligands, especially the diimine ligands, and terahertz spectra are strongly correlated with photoluminescence quantum yields of the complexes. [ABSTRACT FROM AUTHOR]

In this paper, we present the use of the interaction between aromatic rings―usually called π–π interaction―as the main tool in the organization of coordination complexes in a crystal. To do so, we selected coordination compounds with aromatic rings pointing outside the molecules to favor their self-assembly through these interactions. Here, we report the molecular and crystal structures of three Cu(ii) complexes: [Cu2(terpy)2(bz)2](ClO4)2 (1), [Cu2(terpy)2(tfipth)2] (2) and [Cu4(terpy)4(tfipth)2(ClO4)2](ClO4)2 (3), where terpy = 2,2′:6′,2′′ terpyridine, bz = benzoate and tfipth = tetrafluoro-isophthalate. In the three crystals, the interaction between aromatic rings organizes molecules in chains that closely pack with disordered anions or water molecules located in the space between the chains. A study of the Crystal Structure Database (CSD) indicates that the main interaction in terpy molecules is between a lateral ring and the central ring of different molecules and when terpy molecules point in opposite directions, they tend to form chains, suggesting that these interactions can be used as a design tool. The metal complexes were designed to obtain a square pyramidal structure around the metal ion, but we observed a contact between the non-coordinated O (carboxylate) and the Cu(ii) ion. We studied the presence of this interaction and its nature with computational chemistry. [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]

Crystals of 4-methoxyazobenzene move on water surface and the motion is triggered by irradiation with ultraviolet light. The propulsion is produced by dissolution of the photo-generated cis isomer, which is produced by the photoinduced crystal–liquid phase transition. A photoresponsive boat was also prepared by a filter paper adsorbed with azobenzene. [ABSTRACT FROM AUTHOR]

The occurrence of interpenetrated three-dimensional networks has been systematically investigated by the analysis of the crystallographic structural databases, using the program package TOPOS. After our previous reports on interpenetration observed in valence-bonded MOFs, inorganic arrays and hydrogen-bonded organic supramolecular architectures, in this paper we have focused our research on the interpenetrated 3D networks based on hydrogen-bonded metal–organic molecular (0D) and polymeric (1D and 2D) complexes from the Cambridge Structural Database. The current interest for the crystal engineering of new functional materials has prompted many research groups to adopt synthetic strategies implying the use of molecular metal complexes (0D) with suitably exo-oriented hydrogen-bond donor and acceptor groups for the assembly of extended networks. With regard to this we have examined 3D hydrogen-bonded supramolecular arrays formed by finite and infinite motifs of lower dimensionality, analyzing their topologies and looking for their entanglements. We have extracted a comprehensive list including 135 different motifs (71 assembled from 0D, 43 from 1D and 21 from 2D metal–organic motifs) showing the phenomenon of interpenetration (about two thirds not detected in the original papers). These hydrogen-bonded networks include species assembled by one or more building blocks, that are classified within the previously introduced Classes of interpenetration. It is observed that the maximum interpenetration degree is limited to 5-fold and the main (overall) topology is 412.63-pcu. An analysis of the possible relationships between the dimensionality of the building blocks and the resulting network connectivity and topology, and of some factors determining the interpenetration is also attempted, together with a comparison of the present results with those for other families of interpenetrated materials. [ABSTRACT FROM AUTHOR]

We report a magnetically-anisotropic PrCo5 permanent bulk magnet, prepared by a hot deformation method, with crystallographic orientation-dependent magnetic properties. Although the PrCo5 crystals strongly favor the {0001} orientation texture, the crystallographic orientation textures of PrCo5 crystallites differ at various radial locations. From the bulk center to the edge, the c-axis orientation texture decreases from 5.4 MRD to 4.1 MRD, whereas the remanence decreases from 8.93 kGs to 7.58 kGs and the coercivity increases from 4.34 kOe to 6.56 kOe. This paper also reports the alteration of boundary plane orientation textures, resulting from the corresponding energy anisotropy at different locations, and suggests that the development of grain boundaries with lower boundary energies has a significant impact on the magnetic properties with regard to remanence and energy density. The current work therefore proposes an elegant approach to attain desired magnetic properties in PrCo5 magnets by fine-tuning the crystallographic orientation. [ABSTRACT FROM AUTHOR]

Environments with varying temperatures have been shown to beneficially increase the probability of obtaining protein crystals. Therefore, a cycling temperature strategy (CTS) has been proposed for protein crystallization screening. During the practical application of this strategy, it is necessary to know the effective temperature range that promotes crystallization to design a suitable temperature program. In this paper, the effects of different temperature ranges on lysozyme crystallization (or more specifically, nucleation) were investigated. The results show that a small periodic variation in the temperature range of as little as 0.4 K can have a significant effect on the crystallization success rate under some crystallization concentration conditions, confirming that crystallization of lysozyme is very sensitive to temperature variation. Because practical protein crystallization is always performed in an environment with slight temperature variations, the sensitivity of protein crystallization to temperature may provide an explanation for the poor reproducibility of protein crystallization. Further investigation of the CTS on lysozyme crystallization showed that a cycling temperature strategy exerts an effect on protein crystallization by altering the supersaturation caused by changes in temperature. [ABSTRACT FROM AUTHOR]

Morphologically controlled micro-/nanostructures have gained considerable interest as they offer unique properties associated with size, shape, and crystallographic facets. In this paper, we report a simple yet rapid protocol for large scale synthesis of silver microplates (AgMPls) from a silver ammine complex ([Ag(NH3)2]+) under an etching environment containing O2/Cl−, NH4OH/H2O2, and H2O2 capable of dissolving silver crystals except plate structures. H2O2 is employed as the sole reducing agent. Chloride ions are essential for creating an etching environment capable of selective dissolution of singly and multiply twinned crystals, while leaving plate structures unaffected. Without chloride ions, H2O2 reduces the [Ag(NH3)2]+ complex to silver microparticles containing truncated cubes, icosahedra, pentagonal rods, and plate microstructures with icosahedra as the major product. The developed protocol enables environmentally friendly fabrication of highly pure AgMPls and AgMPs directly from the AgCl precipitate. [ABSTRACT FROM AUTHOR]

The article presents abstracts of papers on solid-state and crystalline materials with topics including degradation of organic dyes, preparation of polyacrylic acid/calcium carbonate nanoparticles and organic ionic electro-optic crystals.

(CoxNi1−x)0.85Se nanostructures (NSs) with different shapes (i.e., sheet-like, flower-like, and urchin-like) were synthesized by a sacrificial template method. As far as we know, this paper may be the first work that used (CoxNi1−x)0.85Se NSs as catalysts for reduction of 4-nitrophenol (4-NP) by NaBH4 in aqueous solution. [ABSTRACT FROM AUTHOR]

Mechanochromic luminescence via grinding-induced crystalline-to-amorphous transition in some organic materials has been well illustrated in recent years. Here, we focus on the luminescence reversion process induced by thermal annealing crystallization of a series of tetraphenylethene analogues. Through paired comparisons, we disclosed that the mechano-stimuli can not only destroy the crystallinity of crystalline materials but can also bring a significant effect on the amorphous-to-crystalline transition of amorphous materials. That is, only when an amorphous material underwent mechano-stimuli can it crystallize by thermal annealing to recover its emission. This grinding-facilitated annealing crystallization is rationalized to originate from the twisted and rotatable intramolecular conformation that can be altered by mechano-stimuli. Besides some special usage of the material as security paper or latent memory medium, the study presents new strategies to control the crystallization of organic semiconductors. [ABSTRACT FROM AUTHOR]

This paper presents a detailed configurational analysis of the {100} and {110} crystallographic forms of the spinel sensu stricto MgAl2O4. In order to collect as many structural and energy data as possible about the most stable surface terminations, we have performed accurate calculations, both at the empirical and at the DFT level at 0 K under vacuum, by using a dedicated force field and the hybrid Hartree-Fock/Density Functional B3LYP Hamiltonian, respectively. The configurational analysis performed in this work on MgAl2O4 will be useful for studying all of the minerals belonging to the family of normal spinels (i.e., MgCr2O4). Indeed, the initial configurations found for the (100) and (110) faces of MgAl2O4 are the same for all of the normal spinels. As regards the (100) face, we found that the surface configuration with the lowest surface energy (1.596 J m-2) is associated with the Mg-terminated one. Furthermore, we found an Al-O-terminated (100) configuration with a surface energy value of 2.161 J m-2 that is notably lower than those previously calculated by other authors. This proves that to gain an in-depth knowledge of a crystal surface, it is not sufficient to explore a limited number of terminations (configurations), but it is essential to perform a detailed crystallographic and configurational analysis of the face. In the case of the (110) face and at variance with the (100), the most stable surface configuration (2.752 J m-2) was found to be an Al-O-terminated one. [ABSTRACT FROM AUTHOR]

Supramolecular structures, with ever increasing size ranging from a few up to tens of nanometres, represent an intermediate stage between small molecules and biological macromolecules. Many crystal structures of these large supramolecular assemblies have been solved using dual space algorithms. However, supramolecular assemblies with a capsular shape present a particular challenge for crystallography, especially when they are chiral and composed of only light atoms. In this paper, we show that the application of "routine" macromolecular tools may be of great help in solving the crystal structures of supramolecular assemblies that are otherwise refractory to the routine methods of small molecule crystallography. Specifically, we have applied the method of molecular replacement as implemented in PHASER in order to solve the crystal structure of a chiral organic capsule, which could not be determined using direct or dual space methods. By utilizing various models consisting of well- defined supramolecular "bricks" or modelled structures, we show how model size (fraction of the asymmetric unit) and quality (root mean square deviation from target) influence the success rate of medium sized non-protein structures. The results indicate that supramolecular structures, that are still "small molecules" for macromolecular standards, can be successfully solved using even very small models, down to 25% by weight of the contents of the asymmetric unit. [ABSTRACT FROM AUTHOR]

Melt structure, a fundamental and challenging subject for borate crystal growth, has not been solved for many years. In this paper, a new method has been employed to study the Li2B4O7 melt structure. High temperature Raman spectroscopy has been used to investigate the structural evolvement from a Li2B4O7 crystal to a Li2B4O7 melt. Based on the investigation, a model was proposed to describe the Li2B4O7 melt. The melt is made up of polymer-like boron-oxygen chains; the minimal repeated unit is the B4O6ϕ2 2- (ϕ = bridging oxygen) group which is formed by a B2O4ϕ2 - six-membered ring and a BOϕ2 - triangle linked by a bridging oxygen atom. DFT calculations have verified the melt structure and provided accurate assignments for the vibrational bands present in the Li2B4O7 melt Raman spectrum. [ABSTRACT FROM AUTHOR]

In this paper, the novel straw sheaf-like CuO single crystals have been, for the first time, prepared through a facile two-step process: hydrothermal and subsequent calcination. We have mainly investigated the influences of the copper(II) concentration, the added amount of hexamethylenetetramine (HMT), reaction temperature and time on the samples. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and nitrogen sorption isotherms. The results show that the formed CuO straw sheaves are fairly uniform, and the single straw grows preferentially along the [001] orientation. It is proposed that the CuO straw sheaves form by a crystal splitting growth process. Furthermore, under visible-light irradiation, the CuO straw sheaves exhibit 5.3 times higher activity than the irregular sample for the degradation of rhodamine B (RhB), which has been ascribed to the exposed {110} facets and high crystallinity. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate a scalable process for the precise position-controlled selective growth of GaN nanowire arrays by metalorganic chemical vapor deposition (MOCVD) using a pulsed-mode growth technique. The location, orientation, length, and diameter of each GaN nanowire are controlled via pulsed-mode growth parameters such as growth temperature and precursor injection and interruption durations. The diameter and length of each GaN nanowire are in the ranges of more than 240 nm and 250-1250 nm, respectively, with different vertical-to-lateral aspect ratios that depend on the growth temperature. Also, it is found that a higher growth temperature helps increase the vertical growth rate and reduces the lateral growth rate of GaN nanowire arrays. Furthermore, in the case of longer TMGa injection duration, the Ga-rich region allows the higher lateral growth rate of GaN nanostructures, which leads to a transition in the morphology from nanowires to a thin film, while in the case of longer NH3 injection duration, the surface morphology changes from nanowires to pyramidal structures. In addition, the surface structure can also be controlled by varying the precursor interruption duration. Finally, we report and discuss a growth model for GaN nanowire arrays under pulsed-mode MOCVD growth. [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]

The extended use of self-assembling approaches for the generation of oxide nanostructures with engineered functional properties firstly relies on the ability to control their growth processes. In this paper, we focus on the growth of Ce1−xGdxO2−y(CGO) nanoislands on ABO3substrates (i.e.LaAlO3(LAO)) as a model system to investigate the nucleation and kinetic evolution of epitaxial nanostructures grown by high-throughput ex situmethods based on chemical solution deposition. Fine-tuning of growth conditions enables us to select the crystallographic orientation of CGO leading to two systems with different equilibrium shapes and kinetics. Self-assembled (001)CGO(001)LAO nanostructures grow with stable uniform square-based nanopyramid shape, whereas the nucleation of (011)CGO(001)LAO leads to highly elongated nanowires with enhanced diffusive mobility. At high temperatures, shape selection is merely achieved through a modified growth atmosphere (oxidizing or reducing). However, a temperature-induced nucleation orientation crossover occurs under the reducing growth atmosphere, allowing the tuning of a nanodot-to-nanowire ratio through kinetic control. We prove by XPS that an enhanced concentration of oxygen vacancies in the nanowires is linked to their ultrafast coarsening. The nucleation processes are scrutinized through thermodynamic analysis, and it is concluded that the supersaturation degree controls the nanoislands' orientation. [ABSTRACT FROM AUTHOR]

A family of 9H-thioxanthen-9-one derivatives and two precursors, 2-[(4-bromophenyl)sulfanyl]-5-nitrobenzoic acid and 2-[(4-aminophenyl)sulfanyl]-5-nitrobenzoic acid, were synthesized and studied in order to assess the role of the different substituent groups in determining the supramolecular motifs. From our results we can conclude that Etter's rules are obeyed: whenever present the –COOH head to head strong hydrogen bonding dimer, R22(8) synthon, prevails as the dominant interaction. As for –NH2, the best donor when present also follows the expected hierarchy, an NHO(COOH) was formed in the acid precursor (2) and an NHO(CO) in the thioxanthone (4). The main role played by weaker hydrogen bonds such as CHO, and other intermolecular interactions, π–π and BrO, as well as the geometric restraints of packing patterns shows the energetic interplay governing crystal packing. A common feature is the relation between the π–π stacking and the unit cell dimensions. A new synthon notation, R′, introduced in this paper, refers to the possibility of accounting for intra- and intermolecular interactions into recognizable and recurring aggregate patterns. [ABSTRACT FROM AUTHOR]

This paper illustrates the versatility of mono- and heterobinuclear complexes with dissymmetric compartmental ligands in designing molecular and supramolecular heterometallic systems. Mononuclear complexes with side-off bicompartmental ligands derived from o-vanillin act efficiently, through their empty compartment, as hydrogen-bond receptors and as second coordination sphere ligands. These Schiff- bases are also suitable for synthesizing 3d-3d′ and 3d-4f heterobinuclear complexes. Both 3d-3d′ and 3d-4f complexes can be employed as nodes in obtaining coordination polymers with various dimensionalities and network topologies, as well as interesting magnetic and optical properties. [ABSTRACT FROM AUTHOR]

This paper reports two structurally unique CuCN-terpyridine hybrid networks of 4′-p-tolyl-2, 2′ : 6′, 2″-terpyridine (ttpy) prepared under solvothermal condtions: [(CuCN)5(ttpy)]n(1), [(CuCN)3(ttpy)]n(2). Complex 1features a tri-layer structure with 3-connected binodal (8210)·(8210) topology, while complex 2features unusual honeycomb-like layer structures. The adjacent honeycomb-like layers consist of the opposite handed helical CuCN-ttpy chains. In both complexes, each ttpy coordinates two copper(I) atoms with short Cu–Cu distances, and the side pyridyl group rotates in a certain angle from the central pyridyl plane directing the formation of the diversified networks. [ABSTRACT FROM AUTHOR]

In the present paper, barium carbonate crystals with higher-order superstructures have successfully been synthesized via a rapid microwave-assisted route in the aqueous system with sodium dodecyl sulfate (SDS), employing BaCl2·2 H2O and NaHCO3 as starting reagents. X-Ray powder diffraction (XRD) analysis showed that the product was an orthorhombic BaCO3. Scanning electron microscopy (SEM) observations showed that the higher-order superstructures were formed by the self-assembly of BaCO3 nanoflakes. Some factors, including the microwave heating power, the time, the concentration of SDS, the initial concentration of reactants, pH value of the system and kinds of surfactants, influencing the morphology of the BaCO3 crystals were systematically studied. Researches showed that SDS played a crucial role in the formation of BaCO3 superstructures. [ABSTRACT FROM AUTHOR]

The observations described in this paper address the scientific challenge of predictably self-organizing porphyrin molecules into materials with complex topologies, with an emphasis on rational construction of robust nanoporous solids and systems exhibiting supramolecular chirality. In order to achieve these goals the porphyrin scaffold is deliberately functionalized with different molecular recognition groups prone to engaging in robust supramolecular synthons. The results demonstrate that, while an a priori rigorous prediction of crystal structures is still not possible, the designed patterning of porphyrin-based network and framework architectures via cooperative non-covalent linkers is an achievable task. This lays a solid ground for the successful design, synthesis and characterization of novel functional supramolecular materials that will exhibit unique properties in the areas of sieving, sensing, gas storage, photonics and nonlinear optics, which are unobtainable by the discrete molecular entities. [ABSTRACT FROM AUTHOR]

The shapes of biologically formed calcite crystals are extremely versatile. Numerous studies have addressed the possible biological mechanism of crystal shape regulation. Synthetic assays have shown that the shape and morphology of calcite crystals can be modulated by inorganic or organic solution additives. Hardly any studies have to date discussed the concept of controlling the shape of these crystals by organic nucleating surfaces. We show in this paper that self-assembled monolayers (SAMs) that template calcite nucleation have two pronounced effects: in addition to inducing the highly oriented crystal growth (the phenomenon that we have extensively described in our previous studies), each SAM induces a clear modification of the calcite shape from its equilibrium rhombohedron. We demonstrate that this change in shape originates from the anisotropy of lattice mismatches that develop between the nucleating crystal face and the organic SAM in different directions. We present a model that gives qualitative predictions for the shape of crystals grown on a variety of SAM substrates, as a function of lattice mismatch, and show that these shapes correlate extremely well with the experimental results. We believe that this mechanism might be utilized by organisms in the biomineralization process. [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]