Grafting, self-organization and reactivity of double-decker rare-earth phthalocyanine

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1523-1534 ◽  
Author(s):  
Nadine Witkowski ◽  
Johann Lüder ◽  
Ieva Bidermane ◽  
Mattia Farronato ◽  
Geoffroy Prévot ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Inorganic Materials ◽  
Experimental Investigations ◽  
X Ray Diffraction ◽  
Gold Surfaces ◽  
Double Decker ◽  
Hybrid Devices ◽  
A Charge ◽  
Reactive Surfaces ◽  
Molecule Surface

Unveiling the interplay of semiconducting organic molecules with their environment, such as inorganic materials or atmospheric gas, is the first step to designing hybrid devices with tailored optical, electronic or magnetic properties. The present article focuses on a double-decker lutetium phthalocyanine known as an intrinsic semiconducting molecule, holding a Lu ion in its center, sandwiched between two phthalocyanine rings. Carrying out experimental investigations by means of electron spectroscopies, X-ray diffraction and scanning probe microscopies together with advanced ab initio computations, allows us to unveil how this molecule interacts with weakly or highly reactive surfaces. Our studies reveal that a molecule–surface interaction is evidenced when molecules are deposited on bare silicon or on gold surfaces together with a charge transferred from the substrate to the molecule, affecting to a higher extent the lower ring of the molecule. A new packing of the molecules on gold surfaces is proposed: an eclipse configuration in which molecules are flat and parallel to the surface, even for thick films of several hundreds of nanometers. Surprisingly, a robust tolerance of the double-decker phthalocyanine toward oxygen molecules is demonstrated, leading to weak chemisorption of oxygen below 100 K.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Modulated vacancy ordering in SrGe6−x (x≈0.45)

2019 ◽  
Vol 74 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Ulrich Schwarz ◽  
Rodrigo Castillo ◽  
Aron Wosylus ◽  
Lev Akselrud ◽  
Yurii Prots ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ambient Pressure ◽  
Stoichiometric Composition ◽  
Binary Compound ◽  
Crystal Structure Analysis ◽  
Local Defect ◽  
X Ray Diffraction ◽  
Vacancy Ordering ◽  
Metal Type ◽  
A Charge

AbstractThe structural properties of modulated SrGe6−x (x≈0.45) were investigated by means of single-crystal and powder X-ray diffraction combined with quantum chemical calculations. The framework compound SrGe6−x adopts a defect variant of the EuGa2Ge4-type crystal structure. Samples of the binary compound with nominal compositions 0≤x≤0.5 were synthesized at pressures from 5 to 6 GPa and a temperature of typically 1400 K. The product reveals diffraction peaks of the EuGa2Ge4-type subcell plus additional reflections indicating an ordered superstructure. Detailed crystal structure analysis evidences the incommensurate nature of the superstructure and a modulation of the vacancy ordering in the germanium network. The computations have shown that the non-stoichiometric composition of the framework with its local defect organization affects the calculated charge of the strontium anions. Although the chemical composition is close to a charge-balanced situation, temperature-dependent resistivity measurements showed metal-type conductivity. At ambient pressure SrGe6−x decomposes exothermally and irreversibly at T=680(10) K into SrGe2 and germanium, indicating its metastable nature at ambient pressure.

The conversion of smectite to illite during diagenesis: evidence from some illitic clays from bentonites and sandstones

1985 ◽  
Vol 49 (352) ◽  
pp. 393-400 ◽  
Author(s):  
P. H. Nadeau ◽  
M. J. Wilson ◽  
W. J. McHardy ◽  
J. M. Tait
Keyword(s):  
Organic Molecules ◽  
Thickness Distribution ◽  
Sedimentary Rocks ◽  
Exchangeable Cations ◽  
Diffraction Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Of Burial ◽  
Particle Thickness ◽  
Scanning Electron

AbstractDiagenetic illitic clays from seven North American bentonites of Ordovician, Devonian, and Cretaceous ages and from three subsurface North Sea sandstones of Permian and Jurassic ages have been examined by X-ray diffraction (XRD) and transmission and scanning electron microscopy (TEM and SEM). XRD indicates that the clays from the bentonites are randomly and regularly interstratified illite/smectites (I/S) with 30–90% illite layers, whereas the clays from the Jurassic and Permian sandstones are regularly interstratified I/S, with 80–90% illite layers, and illite respectively. TEM of shadowed materials shows that randomly interstratified I/S consists primarily of mixtures of elementary smectite and ‘illite’ particles (10 and 20Å thick respectively) and that regularly interstratified I/S and illite consist mainly of ‘illite’ particles 20–50 Å thick and > 50 Å thick respectively. Regularly interstratified I/S from bentonites and sandstones are similar with regard to XRD character and particle thickness distribution. These observations can be rationalized if the interstratified XRD character arises from an interparticle diffraction effect, where the smectite interlayers perceived by XRD, result from adsorption of exchangeable cations and water or organic molecules at the interfaces of particles generally < 50Å thick. A neoformation mechanism is proposed by which smectite is converted to illite with increasing depth of burial in sedimentary rocks, based on dissolution of smectite particles and the precipitation/growth of ‘illite’ particles occurring within a population of thin phyllosilicate crystals.

Evolution structurale de la nacrite en fonction de la nature des molécules organiques intercalees

2000 ◽  
Vol 33 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
A. Ben Haj Amara ◽  
H. Ben Rhaiem ◽  
A. Plançon
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Dimethyl Sulfoxide ◽  
Organic Molecules ◽  
Interlayer Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intercalated Compounds ◽  
Xrd Study ◽  
Intercalation Process

Nacrite has been intercalated with two polar organic molecules: dimethyl sulfoxide (DMSO) andN-methylacetamide (NMA). The homogeneous nacrite complexes have been studied by X-ray diffraction (XRD) and infrared (IR) spectroscopy. The XRD study is based on a comparison between experimental and calculated patterns. The structures of the intercalated compounds have been determined, including the mutual positions of the layers after intercalation and the positions of the intercalated molecules in the interlayer space. It has been shown that the intercalation process causes not only a swelling of the interlayer space but also a shift in the mutual in-plane positions of the layers. This shift depends on the nature of the intercalated molecules and is related to their shape and the hydrogen bonds which are established with the surrounding surfaces. For a given molecule, the intercalation process is the same for the different polytypes of the kaolinite family. These XRD results are consistent with those of IR spectroscopy.

First (3 + 2)-dimensional superspace approach to the structure of levyclaudite-(Sb), a member of the cylindrite-type minerals

2006 ◽  
Vol 62 (5) ◽  
pp. 775-789 ◽  
Author(s):  
Michel Evain ◽  
Vaclav Petricek ◽  
Yves Moëlo ◽  
Colette Maurel
Keyword(s):  
Energy Minimization ◽  
Inorganic Compounds ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Layer Compound ◽  
X Ray ◽  
Density Modulation ◽  
Wavelength Control ◽  
A Charge ◽  
Positively Charged

The structure of synthetic levyclaudite-(Sb), approximately (Pb1 − y Sb y S)1.357[Sn1 − x (Cu2) x S2], has been determined by single-crystal X-ray diffraction on the basis of the (3 + 2)-dimensional superspace approach. This misfit-layer compound, of the cylindrite type, results from the combination of two heavily modulated triclinic Q and H subsystems with a common q wavevector and only one shared reciprocal axis (stacking direction). The Q pseudo-tetragonal layer, ∼(Pb0.70Sb0.30S), derived from the NaCl archetype, is positively charged; the H pseudo-hexagonal layer, ∼(Sn0.85Cu0.30S2), derived from the CdI2 archetype, is negatively charged, owing to the replacement of Sn4+ in an octahedral coordination by Cu+ pairs in an opposite triangular coordination. The analysis shows a strong transverse displacive modulation of the two layers, referred to as a `mondulation', correlated to a maximal Sb site occupation factor in the concavity of the Q layer undulation. The wavelength control of the `mondulation' obeys the vernier principle (14cQ ≅ 13cH ), which would correspond to an energy minimization through a charge transfer density modulation wave, common to all two-dimensional misfit-layer inorganic compounds.

scholarly journals Bonding modes of some labile Si compounds studied by charge density analysis

2014 ◽  
Vol 70 (a1) ◽  
pp. C1698-C1698
Author(s):  
Daisuke Hashizume
Keyword(s):  
Organic Molecules ◽  
Expansion Method ◽  
Multipole Expansion ◽  
Bond Critical Point ◽  
X Ray Diffraction ◽  
Density Distributions ◽  
Density Maps ◽  
Multipole Expansion Method ◽  
Density Analysis ◽  
Electron Donation

Some organic molecules containing Si atom(s) are very labile, even if the corresponding carbon analogs are very stable. To gain information on bonding modes of such compounds, we analyzed valence density distribution, which play critical roles in chemistry of molecule, by applying multipole expansion method. Very recently, an imine coordinated silacyclopropan-1-one, 1, has synthesized by Baceiredo, Kato and co-workers.[1] To clarify the bonding mode of 1, the electron density distributions of 1 and its precursor have analyzed by a multiple expansion method using single crystal X-ray diffraction data. As shown in static model density maps, bonding electrons of Si-C bonds distribute on the outside of the silacyclopropane ring (Si1-C1-C2 ring) (Fig. 1a) with largely extent, in compared with that of the precursor, indicating an in-plane pi-interaction on the Si1-C1 and Si1-C2 bonds. On the other hand, the C1-C2 bonding electrons distribute on the bond, and the bond critical point (BCP) is located on the inside of the three membered ring. In addition, the C1-C2 bonding electrons elongates inside the ring toward the Si1 atom, indicating electron donation from sigma(C1-C2)-bond to the Si1 (Fig. 1b). Consequently, these maps propose greater contribution of canonical structures in Fig. 1c.

Cation and vacancy distribution in an artificially oxidized natural spinel

1997 ◽  
Vol 61 (406) ◽  
pp. 411-421 ◽  
Author(s):  
Giorgio Menegazzo ◽  
Susanna Carbonin ◽  
Antonio Della Giusta
Keyword(s):  
Single Crystal ◽  
Tetrahedral Site ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Reflected Light ◽  
Marginal Part ◽  
Influence Of Temperature On ◽  
Vacancy Distribution ◽  
Crystal Structural ◽  
A Charge

AbstractDuring research on the influence of temperature on cation partitioning in natural Mg-Al-Fe2+-Fe3+ spinels, some crystals were accidentally oxidized during heat treatment. The oxidation product, studied by means of single-crystal X-ray diffraction, turned out to be a phase retaining the Fd3m parent spinel structure, but with cell edge a and oxygen coordinate u considerably smaller than the parent ones (a ∼ 8.087 as compared with ∼ 8.111 Å; u ∼ 0.2609 vs. 0.2617–0.2636) and with vacant sites due to oxidation.Assuming that the oxidation process must occur due to the addition of oxygen to the crystal boundary as cations are being preserved and rising in total valence, the site population was determined and compared with that of untreated and heated samples. It was found that, on oxidation, a charge enrichment in the tetrahedral site T had occurred, this phenomenon following that observed during heating at increasing temperatures also in other spinel series. This continuity was always in the direction of an increase in random charge distribution. Cation vacancies produced during oxidation were restricted to the octahedral site M.Examination of bulk sections by reflected light microscopy showed a few hematite lamellae as inclusions in the oxidized samples, not detectable by microprobe analysis or single-crystal structural refinement. However, hematite played a marginal part in oxidation. Vacancy-oxygen distances in oxidized spinels were determined from experimental data in the literature.

Solvothermal synthesis of hollow Eu2O3 microspheres using carbon template-assisted method

2012 ◽  
Vol 66 (8) ◽  
Author(s):  
Li-Xin Zhang ◽  
Yi-Xin Sun ◽  
Hong-Fang Jiu ◽  
Yue-Hua Fu ◽  
Yuan-Zhong Wang ◽  
...  
Keyword(s):  
Solvothermal Synthesis ◽  
Sol Gel ◽  
Hollow Structure ◽  
Inorganic Materials ◽  
Carbon Sphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Productivity ◽  
Carbon Template ◽  
Transmission Electron

AbstractThis work presents a sol-gel carbon sphere template-assisted method of hollow Eu2O3 microspheres preparation. X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), as well as photoluminescence (PL) were used to characterise the products. The formation of hollow structure Eu2O3 microspheres can be assigned to a sol-gel carbon template. Furthermore, this work may confirm that the precursor sol-gel can be loaded onto the inner as well as the outer surface of carbon templates similarly as ions and nanocrystals. The presented method can afford a simple and efficient technique to obtain a series of hollow structure inorganic materials with high productivity.

scholarly journals Synchrotron x-ray diffraction study of a charge stripe order in18-dopedLa1.875Ba0.125−xSrxCuO4

2003 ◽  
Vol 67 (14) ◽  
Author(s):  
H. Kimura ◽  
H. Goka ◽  
M. Fujita ◽  
Y. Noda ◽  
K. Yamada ◽  
...  
Keyword(s):  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stripe Order ◽  
Charge Stripe ◽  
A Charge

Preparation of Porous Carbon and its Composite Materials via the Reaction under Autogenic Pressure at Elevated Temperature (RAPET)

2018 ◽  
Vol 921 ◽  
pp. 60-64
Author(s):  
Ke Xun Li ◽  
Jiang Jiang Ma ◽  
Jie Zhang ◽  
Kun Jia ◽  
Bi Cheng Zhou ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Composite Materials ◽  
Porous Carbon ◽  
Nitrogen Adsorption ◽  
Inorganic Materials ◽  
Bet Surface Area ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
Discharge Performance ◽  
Adsorption Desorption

In this paper, we reported on the preparation of porous materials via a reaction under Autogenic Pressure at Elevated Temperature (RAPET) at 700°Cusing natural product and alkoxides as precursors. The RAPET is a new simple efficient method to prepare inorganic materials. The porous carbon and its composite materials were prepared via the method of RAPET using natural products such as sweet potato, coriander, the absorbent cotton and viscose fiber doped by tetrabutyl titanate (TBOT) and tetraethoxysilane (TEOS). The reaction temperature of RAPET was 700°C. The carbon and its composites were studied with scanning electron microscopy (SEM), X-ray diffraction (XRD) and nitrogen adsorption-desorption measurements. The BET surface area of the materials are different from 4m2/g to 405m2/g. The XRD investigation indicates that the phases of the TiO2 in the carbon/TiO2 composites are anatase. The materials show a certain charge-discharge performance.

Sign in / Sign up

Export Citation Format

Share Document