Silaheterocyclen, XX Aminosubstituierte Vinylchlorsilane und Silaethene: Bausteine zur Synthese von 1,3-Diaza-2-silacyclopentanen / Silaheterocycles, XX Aminosubstituted Vinylchlorosilanes and Silenes: Building Blocks for the Synthesis of 1,3-Diaza-2-silacyclopentanes

1992 ◽  
Vol 47 (10) ◽  
pp. 1377-1385 ◽  
Author(s):  
Norbert Auner ◽  
Erika Penzenstadler ◽  
Eberhardt Herdtweck
Keyword(s):  
Reaction Pathway ◽  
Addition Product ◽  
Building Blocks ◽  
Diels Alder ◽  
Main Reaction ◽  
Intramolecular Rearrangement ◽  
X Ray Diffraction ◽  
Great Tendency ◽  
X Ray ◽  
Frame Work

The amino-substituted vinylchlorosilanes 4-7 are synthesized from N,N,N′-trimethylethylenediamine (8a) or tris(trimethylsilyl)ethylenediamine (8b), Li Bun and organodichlorovinylsilanes. 5 eliminates trimethylchlorosilane when distilled and yields 1,3-diaza-2-silacyclopentane 9, whereas the compounds 6 and 7 show a great tendency to oligomerize. The reaction of 4 with LiBut gives a neopentylsilene intermediate 10 a which can be trapped by isoprene or 1,3-butadiene yielding small amounts of the Diels-Alder products 11 and 12, respectively. The main reaction pathway for 10 a is rearrangement with migration of a Me3Sigroup from nitrogen to the silene’s carbon atom and a new N—Si bond formation to give the diazasilacyclopentane 10 which has been characterized by X-ray diffraction analysis. This intramolecular rearrangement appears to involve a pentacoordinated silene Si-atom. No dimerisation of 10a to a disilacyclobutane is observed. The introduction of a second Si-tris(trimethylsilyl)ethylenediamine substituent at the SiC frame work does not result in silene stabilisation: there is no evidence for Si-hexacoordination in silene 15 nor in the [4+2] cyclo-addition product with isoprene (14).

Axially Chiral Bis(α-amino Acid)s and Their Deamino Analogues. Synthesis and Configurational Assignment

1998 ◽  
Vol 63 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Miloš Tichý ◽  
Luděk Ridvan ◽  
Miloš Buděšínský ◽  
Jiří Závada ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nmr Spectra ◽  
Building Blocks ◽  
X Ray Diffraction ◽  
Amino Groups ◽  
X Ray ◽  
Configurational Assignment ◽  
Symmetry Properties ◽  
Axially Chiral ◽  
Polymeric Structures

The axially chiral bis(α-amino acid)s cis-2 and trans-2 as possible building blocks for polymeric structures of novel type of helicity were prepared. Their configuration has been determined by NMR spectroscopy and, in the case of the trans-isomer, confirmed by single-crystal X-ray diffraction. Analogous pair of stereoisomeric diacids cis-3 and trans-3, devoid of the amino groups, was also prepared and their configuration assigned. The observed differences in the NMR spectra of cis- and trans-isomers of 2 and 3 are discussed from the viewpoint of their different symmetry properties.

Structural Study of an Unusual Diels-Alder Adduct

1992 ◽  
Vol 45 (12) ◽  
pp. 2089 ◽  
Author(s):  
EL Ghisalberti ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Diffraction Study ◽  
Structural Study ◽  
Spectroscopic Studies ◽  
Diels Alder ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Chemical Evidence ◽  
Alder Adduct

The structure of the compound obtained on heating the naturally occurring clerodane furanoditerpene (1) had been formulated as (2) on the basis of spectroscopic studies. A single-crystal X-ray diffraction study on the dihydro derivative of (2) has confirmed this and provides support for the stereochemistry previously assigned to (1) on the basis of chemical evidence.

A New POM-Based Supramolecular Compound: Synthesis, Structure and Adsorptive Property of [Cu(phen)2]3[W6O19]

2014 ◽  
Vol 919-921 ◽  
pp. 2013-2016 ◽  
Author(s):  
Ya Bing Liu ◽  
Hong Jie Wang ◽  
Hong Kai Zhao
Keyword(s):  
Three Dimensional ◽  
Building Blocks ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Hybrid Compound ◽  
Adsorptive Property ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Compound Synthesis ◽  
Metal Organic

A POM - based organice - inorganic hybrid compound with the chemical formula of[Cu (phen)2]3[W6O19] (phen = 1,10-phenanthroline) (1) has been hydrothermally synthesized andstructurally characterized by the elemental analysis, and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic space groupC2/c witha=18.319(4) Å,b= 17.311(4) Å,c= 22.248(4) Å,β= 112.40(3) o,V= 6523(2) Å3,Z= 4, R1= 0.0448, andwR2=0.1218. Compound 1 consists of the [W6O19]3-building blocks and [Cu (phen)2]+metal organic cationic moieties, which are packed together via the extensive hydrogen-bonding interactions to form a three-dimensional supramolecular framework. The adsorption of methylene blue (MB) under UV irradiation with 1 as the heterogeneous adsorbent has been investigated, showing a good adsorptive property of 1 for MB degradation.

scholarly journals In situ X-ray Diffraction Investigation of the Crystallisation of Perfluorinated Ce(IV)-based Metal-Organic Frameworks with UiO-66 and MIL-140 architectures

2020 ◽  
Author(s):  
Stephen Shearan ◽  
Jannick Jacobsen ◽  
Ferdinando Costantino ◽  
Roberto D’Amato ◽  
Dmitri Novikov ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Metal Organic Frameworks ◽  
Building Blocks ◽  
Nucleation And Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rate Determining Step ◽  
Wide Range ◽  
Metal Organic

We report on the results of a thorough <i>in situ</i> synchrotron powder X-ray diffraction study of the crystallisation in aqueous medium of two recently discovered perfluorinated Ce(IV)-based metal-organic frameworks (MOFs), analogues of the already well investigated Zr(IV)-based UiO-66 and MIL-140A, namely, F4_UiO-66(Ce) and F4_MIL-140A(Ce). The two MOFs were originally obtained in pure form in similar conditions, using ammonium cerium nitrate and tetrafluoroterephthalic acid as building blocks, and small variations of the reaction parameters were found to yield mixed phases. Here, we investigate the crystallisation of these compounds <i>in situ</i> in a wide range of conditions, varying parameters such as temperature, amount of the protonation modulator nitric acid (HNO<sub>3</sub>) and amount of the coordination modulator acetic acid (AcOH). When only HNO<sub>3</sub> is present in the reaction environment, F4_MIL-140A(Ce) is obtained as a pure phase. Heating preferentially accelerates nucleation, which becomes rate determining below 57 °C, whereas the modulator influences nucleation and crystal growth to a similar extent. Upon addition of AcOH to the system, alongside HNO<sub>3</sub>, mixed-phased products, consisting of F4_MIL-140A(Ce) and F4_UiO-66(Ce), are obtained. In these conditions, F4_UiO-66(Ce) is always formed faster and no interconversion between the two phases occurs. In the case of F4_UiO-66(Ce), crystal growth is always the rate determining step. An increase in the amount of HNO<sub>3</sub> slows down both nucleation and growth rates for F4_MIL-140A(Ce), whereas nucleation is mainly affected for F4_UiO-66(Ce). In addition, a higher amount HNO<sub>3</sub> favours the formation of F4_MIL-140A(Ce). Similarly, increasing the amount of AcOH leads to slowing down of the nucleation and growth rate, but favours the formation of F4_UiO-66(Ce). The pure F4_UiO-66(Ce) phase could also be obtained when using larger amounts of AcOH in the presence of minimal HNO<sub>3</sub>. Based on these <i>in situ</i> results, a new optimised route to achieving a pure, high quality F4_MIL-140A(Ce) phase in mild conditions (60 °C, 1 h) is also identified.

Cobalt(II) chloride adducts with acetonitrile, propan-2-ol and tetrahydrofuran: considerations on nuclearity, reactivity and synthetic applications

2017 ◽  
Vol 73 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Danilo Stinghen ◽  
André Luis Rüdiger ◽  
Siddhartha O. K. Giese ◽  
Giovana G. Nunes ◽  
Jaísa F. Soares ◽  
...  
Keyword(s):  
Single Molecule ◽  
Building Blocks ◽  
Direct Reaction ◽  
X Ray Diffraction ◽  
Single Molecule Magnets ◽  
X Ray ◽  
Ft Ir ◽  
Bond Network ◽  
Solvent Molecules ◽  
Intramolecular Hydrogen

High-spin cobalt(II) complexes are considered useful building blocks for the synthesis of single-molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl2, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single-crystal X-ray diffraction analyses.trans-Tetrakis(acetonitrile-κN)bis(tetrahydrofuran-κO)cobalt(II) bis[(acetonitrile-κN)trichloridocobaltate(II)], [Co(C2H3N)4(C4H8O)2][CoCl3(C2H3N)]2, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymercatena-poly[[tetrakis(propan-2-ol-κO)cobalt(II)]-μ-chlorido-[dichloridocobalt(II)]-μ-chlorido], [Co2Cl4(C3H8O)4], (2′), was prepared by direct reaction between anhydrous CoCl2and propan-2-ol in an attempt to rationalize the formation of the CoCl2–alcohol adduct (2), probably CoCl2(HOiPr)m. The binuclear complex di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-2κ2Cl-tetrakis(tetrahydrofuran-1κO)dicobalt(II), [Co2Cl4(C4H8O)4], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen-bond network that appears to favour atransarrangement of the chloride ligands in the octahedral moiety; this differs from thecisdisposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.

Using Ultrathin-Film, Modulated Composites to Control the Reaction Mechanism of Ternary Compound Formation

1991 ◽  
Vol 238 ◽  
Author(s):  
Loreli Fister ◽  
David C. Johnson
Keyword(s):  
Ternary Compound ◽  
Reaction Pathway ◽  
Experimental Parameter ◽  
Ultrathin Film ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Compound Formation ◽  
One Dimensional ◽  
X Ray ◽  
Made In

ABSTRACTA predictable, controllable approach to the synthesis of ternary compounds through known intermediates is presented. Thin and ultrathin film superlattices were made in the Mo-Se, Cu-Se and Mo-Cu systems. Differential scanning calorimetry, low- and high-angle x-ray diffraction were used to assess the interdiffusion and nucleation reactions between elemental layers in these one-dimensional crystals. The experimental parameter modulation distance was used to influence the interfacial reactions. The results from each binary system were then used to predict the reaction pathway in the synthesis of a ternary compound, Cu2Mo6Se8. Superlattices with two different lengthscales were investigated. In the first, only one intermediate, MoSe2 which typically crystallizes at ∼200'C, is observed prior to the crystallization of Cu2Mo6Se8. In the second, no crystalline intermediates are observed below 6000 C.

Synthesis and characterization of the new tin borate SnB8O11(OH)4

2018 ◽  
Vol 73 (5) ◽  
pp. 337-348 ◽  
Author(s):  
Sandra Schönegger ◽  
Klaus Wurst ◽  
Gunter Heymann ◽  
Andreas Schaur ◽  
Andreas Saxer ◽  
...  
Keyword(s):  
Hydrothermal Process ◽  
Building Blocks ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermoanalytical Investigations ◽  
Hydrogen Bond Interactions ◽  
Simple Hydrothermal Process

AbstractA new tin(II) borate with the composition SnB8O11(OH)4 was synthesized by a simple hydrothermal process. It crystallizes in the centrosymmetric monoclinic space group P21/n (no. 14) with the lattice parameters a=790.1(1), b=1402.2(2), c=994.8(1) pm, and β=90.40(5)° (Z=4). The new compound SnB8O11(OH)4 is isotypic to PbB8O11(OH)4 and isostructural to BaB8O11(OH)4. The borate layers are built up from fundamental building blocks (FBBs) with the composition [B8O11(OH)4]2−. Four of these FBBs form a nine-membered ring wherein the Sn2+ cations are located. These boron-oxygen layers are further connected by O–H···O hydrogen bond interactions. The characterization of SnB8O11(OH)4 is based on single-crystal X-ray diffraction data, vibrational spectroscopy, DFT calculations, and thermoanalytical investigations including high temperature powder XRD.

Controlled Synthesis of BaF2 Nanorods via Hydrothermal Microemulsion Method

2007 ◽  
Vol 121-123 ◽  
pp. 441-444
Author(s):  
Y.C. Chen ◽  
Y.G. Zhang
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Barium Chloride ◽  
Building Blocks ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Microemulsion Method ◽  
X Ray ◽  
Transmission Electron ◽  
Microemulsion Droplet

BaF2 nanorods were synthesized by hydrothermal microemulsion method using sodium fluoride (NaF) and barium chloride (BaCl2) as the raw materials. The as-prepared products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results showed that the products were composed of BaF2 nanorods with diameters of 18-62 nm and lengths up to 1μm. A directed aggregation growth process mediated by the microemulsion droplet building blocks is proposed for the formation of BaF2 nanorods. Further work is in progress to evaluate the possibility of synthesizing other fluoride 1D nanostructures using a similar method.

Transient Phase Formation During the Growth of Epitaxial CoSi2 by Annealing of Co/Ti Bi-Layers on (100) Si

1995 ◽  
Vol 402 ◽  
Author(s):  
D. J. Miller ◽  
T. I. Selinder ◽  
K. E. Gray
Keyword(s):  
Electron Microscopy ◽  
Reaction Pathway ◽  
Spinel Phase ◽  
Analytical Electron Microscopy ◽  
Inert Gases ◽  
Native Oxide ◽  
Transient Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analytical Electron

AbstractPhase evolution during the annealing of Co/Ti bi-layers on (100) Si has been studied by x-ray diffraction and analytical electron microscopy. X-ray diffraction performed in situ during annealing revealed a reaction pathway involving the formation of a transient phase when epitaxial CoSi2 films were grown. Analytical electron microscopy was used to identify this phase as a spinel-related phase, isostructural with Co2TiO4. This phase grows as a result of the presence of the Ti interlayer and a small amount of oxygen from the annealing ambient. Annealing in vacuum or other purified inert gases yielded polycrystalline CoSi2 films which form via a different reaction pathway that does not involve a spinel phase. This spinel phase may serve both to reduce the native oxide from the underlying Si substrate and to control interdiffusion between Si and Co during the reaction, thereby promoting epitaxial growth.

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