Synthesis, lead lability and ring deformation of three 1,4,8,11,15,18,22,25-octasubstituted phthalocyaninato lead derivatives

2006 ◽  
Vol 10 (10) ◽  
pp. 1202-1211 ◽  
Author(s):  
Paul M. Burnham ◽  
Isabelle Chambrier ◽  
David L. Hughes ◽  
Benjamin Isare ◽  
Richard J. Poynter ◽  
...  
Keyword(s):  
The Other ◽  
Lead Ion ◽  
X Ray Diffraction ◽  
Steric Interactions ◽  
X Ray ◽  
The Core ◽  
Benzene Rings ◽  
Methylene Groups ◽  
The Mean ◽  
Work Up

The syntheses and attempted syntheses of some non-peripherally (1,4,8,11,15,18,22,25) octasubstituted lead phthalocyanines from their corresponding metal-free derivatives are described. Some compounds exhibited lability of the lead ion during work-up to regenerate the starting material. The results of single crystal X-ray diffraction analyses of 1,4,8,11,15,18,22,25-octahexyl-, 1,4,8,11,15,18,22,25-octa-iso-pentyl- and 1,4,8,11,15,18,22,25-octahexylsulfanyl lead phthalocyanines are reported and cast some light on the greater stability of 1,4,8,11,15,18,22,25-octahexylsulfanyl lead phthalocyanine, in terms of ease of loss of the lead ion, over the other two substituted lead phthalocyanines studied. The phthalocyanine cores of all three derivatives adopt a saddle-shaped geometry rather than the saucer-shaped conformation exhibited by unsubstituted lead phthalocyanine. The saddle-shaped conformation would appear to offer a means of relieving steric interactions between the substituents on adjacent benzene rings. That steric interactions are a feature of these molecules is perhaps reflected in the different distortions of the saddle conformations. This is greatest for compound 1,4,8,11,15,18,22,25-octa-iso-pentyl lead phthalocyanine bearing the isopentyl groups, expected to introduce the most interactions, and least for compound 1,4,8,11,15,18,22,25-octahexylsulfanyl lead phthalocyanine where S atoms rather than methylene groups are adjacent to the benzene ring. The molecules of 1,4,8,11,15,18,22,25-octahexyl- and 1,4,8,11,15,18,22,25-octahexylsulfanyl lead phthalocyanine pack together in pairs with their nearest neighbouring molecule; their lead atoms, displaced from the core and directed towards each other. The presence of the S atoms in 1,4,8,11,15,18,22,25-octahexylsulfanyl lead phthalocyanine leads to close Pb … S contacts between the molecules. Attractive Pb … S interactions in this compound may also account for the larger displacement of the Pb from the mean-plane of the four coordinated nitrogen atoms at the centre of the phthalocyanine core than is found for 1,4,8,11,15,18,22,25-octahexyl- and 1,4,8,11,15,18,22,25-octa-iso-pentyl lead phthalocyanines. The molecular packing of 1,4,8,11,15,18,22,25-octa-iso-pentyl lead phthalocyanine is more complex because of the presence of tetrahydrofuran molecules (the solvent of recrystallisation) within the crystal, offering additional interactions with the Pb atoms.

scholarly journals Crystal structure of bis{(S)-1-[2-(diphenylphosphanyl)ferrocenyl]-(R)-ethyl}ammonium bromide dichloromethane monosolvate

2017 ◽  
Vol 73 (2) ◽  
pp. 152-154
Author(s):  
Afrooz Zirakzadeh ◽  
Berthold Stöger ◽  
Karl Kirchner
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
The Other ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Interplanar Angle ◽  
X Ray ◽  
The Mean ◽  
Protonated Ligand

During the synthesis of an FeBr2complex with the PNP ligand (R,R,SFc,SFc)-[Fe2(C5H5)2(C38H35NP2)] (1), single crystals of the dichloromethane monosolvate of the Br−salt of the protonated ligand1H+were obtained serendipitously,i.e.[Fe2(C5H5)2(C38H36NP2)]Br·CH2Cl2. The crystal structure of1H·Br·CH2Cl2was determined by single-crystal X-ray diffraction. The mean bond lengths in the ferrocene units are Fe—C = 2.049 (3) Å and C—C = 1.422 (4) Å within the cyclopentadienyl rings. The mean C—N bond length is 1.523 (4) Å. The interplanar angle between the two connected cyclopentadienyl rings is 49.2 (2)°. One ferrocene moiety adopts a staggered conformation, whereas the other is between staggered and eclipsed. The Br−ions and the CH2Cl2molecules are located in channels extending along <100>. One ammonium H atom forms a hydrogen bond with the Br−ion [H...Br = 2.32 (4) Å and C—H...Br = 172 (3)°]. The second ammonium H atom is not involved in hydrogen bonding.

Annealing Behaviour of Fe-C-N Nanopowder: Formation of Iron/Graphite Core-Shell Structured Nanoparticles

2005 ◽  
Vol 482 ◽  
pp. 187-190 ◽  
Author(s):  
B. David ◽  
N. Pizúrová ◽  
O. Schneeweiss ◽  
Petr Bezdička ◽  
J. Filip ◽  
...  
Keyword(s):  
Gas Phase ◽  
Iron Nanoparticles ◽  
Magnetic Measurements ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Graphite Nanoparticles ◽  
The Mean ◽  
Core Shell Structure

We are reporting the core-shell structured iron/graphite nanoparticles formed by annealing of a nanopowder. The original Fe-C-N based nanopowder has been synthesized by the laser pyrolysis of gas phase reactants. TEM, XRD, Raman spectroscopy, Mössbauer spectroscopy and magnetic measurements were used for its characterization. Nanopowder was heated up to 800°C at ~ 1 Pa vacuum. Presence of iron nanoparticles with the mean diameter of 40 nm in the annealed state of the nanopowder was confirmed from the width of α-Fe X-ray diffraction lines and their core-shell structure was observed under TEM.

Neutron and X-ray Diffraction Study on the Structure of Ultraphosphate Glasses

1997 ◽  
Vol 52 (3) ◽  
pp. 259-269 ◽  
Author(s):  
Uwe Hoppe ◽  
Günter Walter ◽  
Dörte Stachel ◽  
Andrea Barz ◽  
Alex C. Hannon
Keyword(s):  
Crystal Structures ◽  
Coordination Number ◽  
Real Space ◽  
The Other ◽  
Oxide Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Space Resolution ◽  
Epithermal Neutrons ◽  
The Mean

Abstract The high real-space resolution of neutron diffraction experiments which is provided by use of the epithermal neutrons from spallation sources was exploited in order to differentiate the unlike P-O bonds existing in the PO4 units of phosphate glass networks. The 2 P-O distance peaks, separated by about 12 pm, which were found in the zinc and the calcium ultraphosphate glasses studied are assigned to oxygen sites on bridging (OB) and terminal (OT) positions. The mean P-O distances are nearly invariable versus the growing metal oxide content which results from an elongation of the P-OB and P-OT bonds. The bond lengths which are known from the related crystal structures and from ab initio calculations show almost the same behaviour. The discussion of further details of the crystal structures leads to the conclusion that P-OB rather than P-OT distances should show more details in case of diffraction measurements of even higher real-space resolution. The change of the Zn-O coordination number from 6 to 4 versus increasing ZnO content, which was obtained in previous X-ray diffraction experiments, is confirmed by the recent combination of neutron and X-ray diffraction data. On the other hand, the Ca-O coordination number of about 6 is almost invariable.

scholarly journals Crystal structure and computational study of 2,4-dichloro-N-[(E)-(5-nitrothiophen-2-yl)methylidene]aniline

2016 ◽  
Vol 72 (8) ◽  
pp. 1187-1189 ◽  
Author(s):  
Yavuz Köysal ◽  
Hakan Bülbül ◽  
Sümeyye Gümüş ◽  
Erbil Ağar ◽  
Mustafa Serkan Soylu
Keyword(s):  
Crystal Structure ◽  
Computational Study ◽  
Three Dimensional ◽  
Maximum Deviation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compound C ◽  
Benzene Rings ◽  
The Mean ◽  
Good Agreement

The title compound, C11H6Cl2N2O2S, is a Schiff base that incorporates an N-bound 2,4-dichlorophenyl and a C-bound 5-nitrothiophene ring. The molecule is approximately planar, the maximum deviation from the mean plane being 0.233 (4) Å for the C=N N atom. The dihedral angle between the benzene and thiophene rings is 9.7 (2)°. The C=N double bond has anEconfiguration. The crystal structure features C—H...O hydrogen bonds,forming sheets parallel to (10-1), and π–π stacking interactions between symmetry-related thiophene and benzene rings, in which the distance between adjacent ring centroids is 3.707 (4) Å, forming a three-dimensional supramolecular structure. Geometric parameters from quantum-chemical calculations are in good agreement with experimental X-ray diffraction results.

Isomorphous replacement in electron diffraction of wet crystals of rat hemoglobin

1983 ◽  
Vol 41 ◽  
pp. 446-447
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Heavy Atom ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Isomorphous Replacement ◽  
Structure Factors ◽  
Diffraction Structure ◽  
The Mean

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.

The Electron Effect of Aromatic Group: Control Conformation of 2-Aromatic Cyclododecanone Derivatives

2020 ◽  
Vol 24 (10) ◽  
pp. 1139-1147
Author(s):  
Yang Mingyan ◽  
Wang Daoquan ◽  
Wang Mingan
Keyword(s):  
1H Nmr ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
The Other ◽  
Repulsive Interaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Effect ◽  
Group Control

2-Phenylcyclododecanone and 2-cyclohexylcyclododecanone derivatives were synthesized and characterized by 1H NMR, 13C NMR, HR-ESI-MS and X-ray diffraction. Their preferred conformations were analyzed by the coupling constants in the 1H NMR spectra and X-ray diffraction, which showed the skeleton ring of these derivatives containing [3333]-2-one conformation, and the phenyl groups were located at the side-exo position of [3333]-2-one conformation due to the strong π-π repulsive interaction between the π- electron of benzene ring and π-electron of carbonyl group. The cyclohexyl groups were located at the corner-syn or the side-exo position of [3333]-2-one conformation depending on the hindrance of the other substituted groups. The π-π electron effect played a crucial role in efficiently controlling the preferred conformation of 2-aromatic cyclododecanone and the other 2-aromatic macrocyclic derivatives with the similar preferred square and rectangular conformations.

scholarly journals Preparation of high-entropy carbides by different sintering techniques

2021 ◽  
Vol 56 (19) ◽  
pp. 11237-11247 ◽  
Author(s):  
Johannes Pötschke ◽  
Manisha Dahal ◽  
Mathias Herrmann ◽  
Anne Vornberger ◽  
Björn Matthey ◽  
...  
Keyword(s):  
Grain Size ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Vacuum Sintering ◽  
X Ray ◽  
High Entropy ◽  
Mean Grain Size ◽  
The Mean ◽  
Gas Pressure Sintering ◽  
Hardness Values

AbstractDense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure sintering/sinter–HIP at 1900 °C and 100 bar Ar, vacuum sintering at 2250 °C and 0.001 bar as well as SPS/FAST at 2000 °C and 60 MPa pressure. The relative density varied from 97.9 to 100%, with SPS producing 100% dense samples with both compositions. Grain size measurements showed that the substitution of Hf with W leads to an increase in the mean grain size of 5–10 times the size of the (Hf, Ta, Nb, Ti, V,)C samples. Vacuum-sintered samples showed uniform grain size distribution regardless of composition. EDS mapping revealed the formation of a solid solution with no intermetallic phases or element clustering. X-ray diffraction analysis showed the structure of mostly single-phase cubic high-entropy carbides. Hardness measurements revealed that (Hf, Ta, Nb, Ti, V)C samples possess higher hardness values than (Ta, Nb, Ti, V, W)C samples.

Dalnegroite, Tl5–xPb2x(As,Sb)2l–xS34, a new thallium sulphosalt from Lengenbach quarry, Binntal, Switzerland

2009 ◽  
Vol 73 (6) ◽  
pp. 1027-1032 ◽  
Author(s):  
F. Nestola ◽  
A. Guastoni ◽  
L. Bindi ◽  
L. Secco
Keyword(s):  
Polarized Light ◽  
New Mineral ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Concentrations ◽  
Reflected Light ◽  
Mohs Hardness ◽  
The Mean ◽  
The University ◽  
Probable Space

AbstractDalnegroite, ideally Tl4Pb2(As12Sb8)Σ20S34, is a new mineral from Lengenbach, Binntal, Switzerland. It occurs as anhedral to subhedral grains up to 200 μm across, closely associated with realgar, pyrite, Sb-rich seligmanite in a gangue of dolomite. Dalnegroite is opaque with a submetallic lustre and shows a brownish-red streak. It is brittle; the Vickers hardness (VHN25) is 87 kg mm-2(range: 69—101) (Mohs hardness ∼3—3½). In reflected light, dalnegroite is highly bireflectant and weakly pleochroic, from white to a slightly greenish-grey. In cross-polarized light, it is highly anisotropic with bluish to green rotation tints and red internal reflections.According to chemical and X-ray diffraction data, dalnegroite appears to be isotypic with chabournéite, Tl5-xPb2x(Sb,As)21-xS34. It is triclinic, probable space groupP1, witha= 16.217(7) Å,b= 42.544(9) Å,c= 8.557(4) Å, α = 95.72(4)°, β = 90.25(4)°, γ = 96.78(4)°,V= 5832(4) Å3,Z= 4.The nine strongest powder-diffraction lines [d(Å) (I/I0) (hkl)] are: 3.927 (100) (10 0); 3.775 (45) (22); 3.685 (45) (60); 3.620 (50) (440); 3.124 (50) (2); 2.929 (60) (42); 2.850 (70) (42); 2.579 (45) (02); 2.097 (60) (024). The mean of 11 electron microprobe analyses gave elemental concentrations as follows: Pb 10.09(1) wt.%, Tl 20.36(1), Sb 23.95(1), As 21.33(8), S 26.16(8), totalling 101.95 wt.%, corresponding to Tl4.15Pb2.03(As11.86Sb8.20)S34. The new mineral is named for Alberto Dal Negro, Professor in Mineralogy and Crystallography at the University of Padova since 1976.

scholarly journals Rapid four-component synthesis of dihydropyrano[2,3-c]pyrazoles using nano-eggshell/Ti(IV) as a highly compatible natural based catalyst

BMC Chemistry ◽  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Arefeh Dehghani Tafti ◽  
Bi Bi Fatemeh Mirjalili ◽  
Abdolhamid Bamoniri ◽  
Naeimeh Salehi
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Reaction Times ◽  
Diffraction Field ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Work Up

AbstractNano-eggshell/Ti(IV) as a novel naturally based catalyst was prepared, characterized and applied for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives. The characterization of nano-eggshell/Ti(IV) was performed using Fourier Transform Infrared spectroscopy, X-ray Diffraction, Field Emission Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, and Thermo Gravimetric Analysis. Dihydropyrano[2,3-c]pyrazoles were synthesized in the presence of nano-eggshell/Ti(IV) via a four component reaction of aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate at room temperature under solvent free conditions. The principal affairs of this procedure are mild condition, short reaction times, easy work-up, high yields, reusability of the catalyst and the absence of toxic organic solvents.

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

Sign in / Sign up

Export Citation Format

Share Document