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Crystals, Volume 5, Issue 1 (March 2015), Pages 1-171

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Editorial

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Open AccessEditorial Acknowledgement to Reviewers of Crystals in 2014
Crystals 2015, 5(1), 45-46; doi:10.3390/cryst5010045
Received: 8 January 2015 / Accepted: 8 January 2015 / Published: 8 January 2015
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Abstract
The editors of Crystals would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2014:[...] Full article

Research

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Open AccessArticle Structure and Magnetic Properties of Ce3(Ni/Al/Ga)11—A New Phase with the La3Al11 Structure Type
Crystals 2015, 5(1), 1-8; doi:10.3390/cryst5010001
Received: 13 November 2014 / Accepted: 18 December 2014 / Published: 29 December 2014
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Abstract
Single crystals of Ce3(Ni/Al/Ga)11 were obtained from an Al flux reaction. Single crystals of the title compound crystallizing in the orthorhombic space group Immm (No. 71, Z = 2) with a = 436.38(14), b = 1004.5(3) and c = 1293.4(4)
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Single crystals of Ce3(Ni/Al/Ga)11 were obtained from an Al flux reaction. Single crystals of the title compound crystallizing in the orthorhombic space group Immm (No. 71, Z = 2) with a = 436.38(14), b = 1004.5(3) and c = 1293.4(4) pm. This is a standardized unit cell of the previously published La3Al11 structure type. Wavelength dispersive microprobe provides the composition of Ce3.11(1)Ni0.03(1)Al8.95(1)Ga1.90(1). Single crystal refinement provides the composition Ce3Ni0.08Al9.13Ga1.78 with substitution of the Ni and Ga on the Al1 and Al4 sites with the Al2 and Al3 solely occupied by Al. Magnetic susceptibility measurements reveal antiferromagnetic ordering with TN = 4.8 K and there is no evidence for a ferromagnetic ordering that has been reported for Ce3Al11. The effective magnetic moment was found to be μeff = 1.9μB/Ce, which is lower than the expected value for trivalent Ce (2.54μB/Ce). Full article
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Open AccessCommunication Synthesis and Molecular Structure of 2-(Diphenylphosphano)phenyl Benzoate Borane Adduct
Crystals 2015, 5(1), 9-13; doi:10.3390/cryst5010009
Received: 5 November 2014 / Accepted: 12 December 2014 / Published: 29 December 2014
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Abstract
The crystal and molecular structure of 2-(diphenylphosphano)phenyl benzoate borane adduct are reported. The title compound crystallizes from a petroleum ether/ethyl acetate mixture in the triclinic space group P with two molecules in the unit cell. The unit cell parameters are: a = 8.67(1)
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The crystal and molecular structure of 2-(diphenylphosphano)phenyl benzoate borane adduct are reported. The title compound crystallizes from a petroleum ether/ethyl acetate mixture in the triclinic space group P with two molecules in the unit cell. The unit cell parameters are: a = 8.67(1) Å, b = 9.202(1) Å, c = 14.224(2) Å; α = 72.600(7)°, β = 73.577(7)°, γ = 84.349(7)° and V = 1039.5(2) Å3. Bond lengths and angles are typical for this phosphane borane adduct. Full article
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Open AccessArticle Bloch Modes and Evanescent Modes of Photonic Crystals: Weak Form Solutions Based on Accurate Interface Triangulation
Crystals 2015, 5(1), 14-44; doi:10.3390/cryst5010014
Received: 20 August 2014 / Accepted: 10 December 2014 / Published: 5 January 2015
Cited by 5 | PDF Full-text (6548 KB) | HTML Full-text | XML Full-text
Abstract
We propose a new approach to calculate the complex photonic band structure, both purely dispersive and evanescent Bloch modes of a finite range, of arbitrary three-dimensional photonic crystals. Our method, based on a well-established plane wave expansion and the weak form solution of
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We propose a new approach to calculate the complex photonic band structure, both purely dispersive and evanescent Bloch modes of a finite range, of arbitrary three-dimensional photonic crystals. Our method, based on a well-established plane wave expansion and the weak form solution of Maxwell’s equations, computes the Fourier components of periodic structures composed of distinct homogeneous material domains from a triangulated mesh representation of the inter-material interfaces; this allows substantially more accurate representations of the geometry of complex photonic crystals than the conventional representation by a cubic voxel grid. Our method works for general two-phase composite materials, consisting of bi-anisotropic materials with tensor-valued dielectric and magnetic permittivities ε and μ and coupling matrices ς. We demonstrate for the Bragg mirror and a simple cubic crystal closely related to the Kelvin foam that relatively small numbers of Fourier components are sufficient to yield good convergence of the eigenvalues, making this method viable, despite its computational complexity. As an application, we use the single gyroid crystal to demonstrate that the consideration of both conventional and evanescent Bloch modes is necessary to predict the key features of the reflectance spectrum by analysis of the band structure, in particular for light incident along the cubic [111] direction. Full article
(This article belongs to the Special Issue Photonic Crystals)
Open AccessArticle High-Yield Synthesis of Helical Carbon Nanofibers Using Iron Oxide Fine Powder as a Catalyst
Crystals 2015, 5(1), 47-60; doi:10.3390/cryst5010047
Received: 15 September 2014 / Accepted: 22 December 2014 / Published: 8 January 2015
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Abstract
Carbon nanocoil (CNC), which is synthesized by a catalytic chemical vapor deposition (CCVD) method, has a coil diameter of 300–900 nm and a length of several tens of μm. Although it is very small, CNC is predicted to have a high mechanical strength
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Carbon nanocoil (CNC), which is synthesized by a catalytic chemical vapor deposition (CCVD) method, has a coil diameter of 300–900 nm and a length of several tens of μm. Although it is very small, CNC is predicted to have a high mechanical strength and hence is expected to have a use in nanodevices such as electromagnetic wave absorbers and field emitters. For nanodevice applications, it is necessary to synthesize CNC in high yield and purity. In this study, we improved the conditions of catalytic layer formation and CCVD. Using optimized CVD conditions, a CNC layer with a thickness of >40 μm was grown from a SnO2/Fe2O3/SnO2 catalyst on a substrate, and its purity increased to 81% ± 2%. Full article
(This article belongs to the Special Issue Carbon Nanostructures)
Open AccessArticle Band Structure of Photonic Crystals Fabricated by Two-Photon Polymerization
Crystals 2015, 5(1), 61-73; doi:10.3390/cryst5010061
Received: 16 July 2014 / Accepted: 29 September 2014 / Published: 13 January 2015
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Abstract
We study theoretically the band-gap structures of several types of three-dimensional photonic crystals with the fcc lattice symmetry: synthetic opals, inverted yablonovite and woodpile. The samples of inverted yablonovite, inverted yablonovite with a glassy superstructure and woodpile are fabricated by two-photon polymerization through
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We study theoretically the band-gap structures of several types of three-dimensional photonic crystals with the fcc lattice symmetry: synthetic opals, inverted yablonovite and woodpile. The samples of inverted yablonovite, inverted yablonovite with a glassy superstructure and woodpile are fabricated by two-photon polymerization through a direct laser writing technique, which allows the creation of complex three-dimensional photonic crystals with a resolution better than 100 nm. A material is polymerized along the trace of a moving laser focus, thus enabling the fabrication of any desirable three-dimensional structure by direct “recording” into the volume of a photosensitive material. The correspondence of the structures of the fabricated samples to the expected fcc lattices is confirmed by scanning electron microscopy. We discuss theoretically how the complete photonic band-gap is modified by structural and dielectric parameters. We demonstrate that the photonic properties of opal and yablonovite are opposite: the complete photonic band gap appears in the inverted opal, and direct yablonovite is absent in direct opal and inverted yablonovite. Full article
(This article belongs to the Special Issue Photonic Crystals)
Open AccessArticle Synthesis and Reactivity of Novel Boranes Derived from Bulky Salicylaldimines: The Molecular Structure of a Maltolato Compound
Crystals 2015, 5(1), 91-99; doi:10.3390/cryst5010091
Received: 25 December 2014 / Revised: 12 January 2015 / Accepted: 21 January 2015 / Published: 5 February 2015
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Abstract
Reductive amination of salicylaldehyde or 3,5-di-tert-butylsalicylaldehyde and 1-adamantylamine using NaBH4 gave the corresponding aminoalcohols in high yields. Subsequent addition of one equivalent of H3B·SMe2 to the aminoalcohols, with loss of two equivalents of dihydrogen, resulted in the
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Reductive amination of salicylaldehyde or 3,5-di-tert-butylsalicylaldehyde and 1-adamantylamine using NaBH4 gave the corresponding aminoalcohols in high yields. Subsequent addition of one equivalent of H3B·SMe2 to the aminoalcohols, with loss of two equivalents of dihydrogen, resulted in the formation of adamantanyl oxazaborinanes (1a,b). The molecular structure of 1b was studied by a single crystal X-ray diffraction study. Crystals were obtained from a saturated Et2O solution and belong to the triclinic space group Pī with unit cell parameters a = 9.1267(4) Å; b = 11.676(2) Å; c = 12.240(3) Å; α = 66.840(3)°; β = 78.529(3)°; and γ = 67.354(3)°. The molecular structure of the addition product (2a) arising from maltol and 1a was also confirmed by single crystal X-ray diffraction. Crystals were obtained from a saturated 1:2 mixture of toluene/Et2O and belong to the orthorhombic space group Pna2(1) with unit cell parameters a = 18.519(6) Å; b = 17.315(5) Å; and c = 12.680(4) Å. The asymmetric unit contains two molecules that differ slightly in some of the dihedral angles. Full article
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Open AccessArticle Synthesis, Crystal and Molecular Structure Studies and DFT Calculations of Phenyl Quinoline-2-Carboxylate and 2-Methoxyphenyl Quinoline-2-Carboxylate; Two New Quinoline-2 Carboxylic Derivatives
Crystals 2015, 5(1), 100-115; doi:10.3390/cryst5010100
Received: 15 December 2014 / Revised: 8 January 2015 / Accepted: 12 January 2015 / Published: 12 February 2015
Cited by 2 | PDF Full-text (20350 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The crystal and molecular structures of the title compounds, phenyl quinoline-2-carboxylate and 2-methoxyphenyl quinoline-2-carboxylate, two new derivatives of quinolone-2-carboxylic acid, are reported and confirmed by single crystal X-ray diffraction and spectroscopic data. Compound (I), C16H11NO2,
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The crystal and molecular structures of the title compounds, phenyl quinoline-2-carboxylate and 2-methoxyphenyl quinoline-2-carboxylate, two new derivatives of quinolone-2-carboxylic acid, are reported and confirmed by single crystal X-ray diffraction and spectroscopic data. Compound (I), C16H11NO2, crystallizes in the monoclinic space group P21/c, with 8 molecules in the unit cell. The unit cell parameters are a = 14.7910(3) Å; b = 5.76446(12) Å; c = 28.4012(6) Å; β = 99.043(2)°; V = 2391.45(9) Å3. Compound (II), C17H13NO5, crystallizes in the monoclinic space group P21/n with 4 molecules in the unit cell. The unit cell parameters are a = 9.6095(3) Å; b = 10.8040(3) Å; c = 13.2427(4) Å; β = 102.012(3)°; V = 1344.76(7) Å3. Density functional theory (DFT) geometry optimized molecular orbital calculations were performed and frontier molecular orbitals of each compound are displayed. Correlation between the calculated molecular orbital energies (eV) for the surfaces of the frontier molecular orbitals to the electronic excitation transitions from the absorption spectra of each compound has been proposed. Additionally, similar correlations observed among six closely related compounds examining small structural differences to their frontier molecular orbital surfaces and from their DFT molecular orbital energies, provide further support for the suggested assignments of the title compounds. Full article
Open AccessArticle Controlled Deposition of Tin Oxide and Silver Nanoparticles Using Microcontact Printing
Crystals 2015, 5(1), 116-142; doi:10.3390/cryst5010116
Received: 2 October 2014 / Accepted: 4 February 2015 / Published: 13 February 2015
Cited by 3 | PDF Full-text (30112 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This report describes extensive studies of deposition processes involving tin oxide (SnOx) nanoparticles on smooth glass surfaces. We demonstrate the use of smooth films of these nanoparticles as a platform for spatially-selective electroless deposition of silver by soft lithographic stamping. The
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This report describes extensive studies of deposition processes involving tin oxide (SnOx) nanoparticles on smooth glass surfaces. We demonstrate the use of smooth films of these nanoparticles as a platform for spatially-selective electroless deposition of silver by soft lithographic stamping. The edge and height roughness of the depositing metallic films are 100 nm and 20 nm, respectively, controlled by the intrinsic size of the nanoparticles. Mixtures of alcohols as capping agents provide further control over the size and shape of nanoparticles clusters. The distribution of cluster heights obtained by atomic force microscopy (AFM) is modeled through a modified heterogeneous nucleation theory as well as Oswald ripening. The thermodynamic modeling of the wetting properties of nanoparticles aggregates provides insight into their mechanism of formation and how their properties might be further exploited in wide-ranging applications. Full article
(This article belongs to the Special Issue Nanostructured Oxide Crystals)
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Open AccessArticle TEV—A Program for the Determination of the Thermal Expansion Tensor from Diffraction Data
Crystals 2015, 5(1), 143-153; doi:10.3390/cryst5010143
Received: 6 January 2015 / Accepted: 4 February 2015 / Published: 16 February 2015
Cited by 5 | PDF Full-text (726 KB) | HTML Full-text | XML Full-text
Abstract
TEV (Thermal Expansion Visualizing) is a user-friendly program for the calculation of the thermal expansion tensor αij from diffraction data. Unit cell parameters determined from temperature dependent data collections can be provided as input. An intuitive graphical user interface enables fitting of
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TEV (Thermal Expansion Visualizing) is a user-friendly program for the calculation of the thermal expansion tensor αij from diffraction data. Unit cell parameters determined from temperature dependent data collections can be provided as input. An intuitive graphical user interface enables fitting of the evolution of individual lattice parameters to polynomials up to fifth order. Alternatively, polynomial representations obtained from other fitting programs or from the literature can be entered. The polynomials and their derivatives are employed for the calculation of the tensor components of αij in the infinitesimal limit. The tensor components, eigenvalues, eigenvectors and their angles with the crystallographic axes can be evaluated for individual temperatures or for temperature ranges. Values of the tensor in directions parallel to either [uvw]’s of the crystal lattice or vectors (hkl) of reciprocal space can be calculated. Finally, the 3-D representation surface for the second rank tensor and pre- or user-defined 2-D sections can be plotted and saved in a bitmap format. TEV is written in JAVA. The distribution contains an EXE-file for Windows users and a system independent JAR-file for running the software under Linux and Mac OS X. The program can be downloaded from the following link: http://www.uibk.ac.at/mineralogie/downloads/TEV.html (Institute of Mineralogy and Petrography, University of Innsbruck, Innsbruck, Austria) Full article
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Open AccessArticle Infrared Extinction of a Dye-Doped (Polymer/Liquid Crystal) Composite Film
Crystals 2015, 5(1), 163-171; doi:10.3390/cryst5010163
Received: 16 January 2015 / Revised: 28 January 2015 / Accepted: 4 February 2015 / Published: 2 March 2015
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Abstract
Infrared extinction of a dye-doped (polymer/liquid crystal) composite film was investigated. It is found that doping a metal-complex dye into the liquid crystal extended the operation wavelength to an optical fiber communication wavelength of about 1.5 μm. An aperture placed behind the composite
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Infrared extinction of a dye-doped (polymer/liquid crystal) composite film was investigated. It is found that doping a metal-complex dye into the liquid crystal extended the operation wavelength to an optical fiber communication wavelength of about 1.5 μm. An aperture placed behind the composite film greatly improves an extinction ratio, which suggests the film functions on the basis of light scattering. Some experimental results agree to Rayleigh scattering. The film exhibits the high extinction ratio of 51 or 17.1 dB and a low polarization dependent loss of 7.6% or 0.32 dB and, then, it could be applied to a telecommunication device such as a variable optical attenuator. Full article
(This article belongs to the Special Issue Liquid Crystal Films)

Review

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Open AccessReview Dispersability of Carbon Nanotubes in Biopolymer-Based Fluids
Crystals 2015, 5(1), 74-90; doi:10.3390/cryst5010074
Received: 30 September 2014 / Accepted: 19 December 2014 / Published: 16 January 2015
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Abstract
In this review the dispersability of carbon nanotubes in aqueous solutions containing proteins, or nucleic acids, is discussed. Data reported previously are complemented by unpublished ones. In the mentioned nanotube-based systems several different phases are observed, depending on the type and concentration of
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In this review the dispersability of carbon nanotubes in aqueous solutions containing proteins, or nucleic acids, is discussed. Data reported previously are complemented by unpublished ones. In the mentioned nanotube-based systems several different phases are observed, depending on the type and concentration of biopolymer, as well as the amount of dispersed nanotubes. The phase behavior depends on how much biopolymers are adsorbing, and, naturally, on the molecular details of the adsorbents. Proper modulation of nanotube/biopolymer interactions helps switching between repulsive and attractive regimes. Dispersion or phase separation take place, respectively, and the formation of liquid crystalline phases or gels may prevail with respect to dispersions. We report on systems containing ss-DNA- and lysozyme-stabilized nanotubes, representative of different organization modes. In the former case, ss-DNA rolls around CNTs and ensures complete coverage. Conversely, proteins randomly and non-cooperatively adsorb onto nanotubes. The two functionalization mechanisms are significantly different. A fine-tuning of temperature, added polymer, pH, and/or ionic strength conditions induces the formation of a given supra-molecular organization mode. The biopolymer physico-chemical properties are relevant to induce the formation of different phases made of carbon nanotubes. Full article
(This article belongs to the Special Issue Carbon Nanostructures)
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Open AccessReview Let’s Talk about MOFs—Topology and Terminology of Metal-Organic Frameworks and Why We Need Them
Crystals 2015, 5(1), 154-162; doi:10.3390/cryst5010154
Received: 30 November 2014 / Accepted: 7 February 2015 / Published: 16 February 2015
Cited by 15 | PDF Full-text (6904 KB) | HTML Full-text | XML Full-text
Abstract
Recent IUPAC (The International Union for Pure and Applied Chemistry) recommendations on the terminology of metal-organic frameworks are reviewed and the background to a proposed topology classification is discussed. The various numerical designators such as point symbols, vertex symbols and transitivity are also
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Recent IUPAC (The International Union for Pure and Applied Chemistry) recommendations on the terminology of metal-organic frameworks are reviewed and the background to a proposed topology classification is discussed. The various numerical designators such as point symbols, vertex symbols and transitivity are also explained and their importance elucidated. Full article
(This article belongs to the Special Issue Metal-Organic Frameworks (MOFs): Energy and Informatics)
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