scholarly journals HPLC monitored synthesis of R2NCH2 substituted benzene derivatives used as (C,N)-ligands for organometallic compounds

2004 ◽  
Vol 2 (4) ◽  
pp. 563-572 ◽  
Author(s):  
Loredana Soran ◽  
Virginia Coman ◽  
Albert Soran ◽  
Cristian Silvestru
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Narrow Range ◽  
Organometallic Compounds ◽  
Hplc Method ◽  
Benzene Derivatives ◽  
Straight Lines ◽  
Correlation Factors ◽  
Good Agreement ◽  
Hplc Data

Abstract2-(Diethylaminomethyl)phenyl bromide and 1,3-bis(dimethylaminomethyl)-benzene, useful ligands for the synthesis of hypervalent organometallic compounds, were prepared and characterized by NMR (1H, 13C, 2D experiments) spectroscopy. Their synthesis was monitored by the HPLC method. The compounds were eluted on a Nucleosil 120 Si column (5 μm, 25×0.4 cm) with n-hexane at room temperature using a 1.0 ml/min flow-rate. The maximum values of absorbance for the studied compounds, excepting the diethylamine, were located in a narrow range around 212 nm, the wavelength used for their UV detection. The diethylamine was detected at 190 nm. The calibration curves are straight lines with correlation factors r>0.995. The HPLC data are in good agreement with those provided by NMR spectroscopy.

INDUCED INFRARED ABSORPTION OF NITROGEN AND NITROGEN – FOREIGN GAS MIXTURES

1965 ◽  
Vol 43 (12) ◽  
pp. 2331-2343 ◽  
Author(s):  
S. Paddi Reddy ◽  
C. W. Cho
Keyword(s):  
Room Temperature ◽  
Gas Mixtures ◽  
Fundamental Vibration ◽  
Molecular Constants ◽  
Pure Nitrogen ◽  
Helium Mixtures ◽  
Vibration Rotation ◽  
The Individual ◽  
Straight Lines ◽  
Good Agreement

The pressure-induced fundamental vibration–rotation absorption band of nitrogen was studied in the pure gas and in nitrogen–argon, nitrogen–hydrogen, and nitrogen–helium mixtures at room temperature for pressures up to 1 500 atm. The shapes of the absorption profiles obtained in each case were discussed. The enhancement absorption profiles of nitrogen–argon mixtures exhibited the sharpening of the individual branches of the fundamental band with a small frequency shift, while those of nitrogen–hydrogen and nitrogen–helium mixtures indicated a splitting of the Q branch. Binary and ternary absorption coefficients were determined for pure nitrogen and nitrogen – foreign gas mixtures. The graph drawn with (1/ρa2) ∫α(ν)dν vs. ρa for pure nitrogen and those drawn with (1/ρaρb) (∫α(ν)dν)enhancement vs. ρb for mixtures were found to be straight lines. Except for nitrogen–helium mixtures all these straight lines had negative slopes, and this was interpreted as a partial cancelation of the induced moments due to ternary collisions. Applying the theory of Van Kranendonk and using the known molecular constants, the molecular quadrupole moment Q of nitrogen and its derivative Q′ with respect to the internuclear distance at its equilibrium position were determined. The values of Q and Q′ were obtained as 1.1ea02 and 0.97ea0 respectively; the value of Q is in good agreement with that determined by previous investigators.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

Arene Dearomatization via Radical Hydroarylation

2019 ◽  
Author(s):  
Autumn Flynn ◽  
Kelly McDaniel ◽  
Meredith Hughes ◽  
David Vogt ◽  
Nathan Jui
Keyword(s):  
Precious Metal ◽  
Room Temperature ◽  
Aryl Halide ◽  
Solvent System ◽  
Benzene Derivatives ◽  
Green Solvent ◽  
Photocatalytic System

A photocatalytic system for the dearomative hydroarylation of benzene derivatives has been developed. Using a combination of an organic photoredox catalyst and an amine reductant, this process operates through a reductive radical-polar crossover mechanism where aryl halide reduction triggers a regioselective cyclization event, giving rise to a range of complex spirocyclic cyclohexadienes. This light-driven protocol functions at room temperature in a green solvent system (aq. MeCN), without the need for precious metal-based catalysts or reagents, or the generation of stoichiometric metal byproducts.

scholarly journals Structure and dynamics of room temperature ionic liquids with bromide anion: results from 81 Br NMR spectroscopy

2015 ◽  
Vol 53 (5) ◽  
pp. 369-378 ◽  
Author(s):  
Takatsugu Endo ◽  
Mamoru Imanari ◽  
Yuki Hidaka ◽  
Hiroko Seki ◽  
Keiko Nishikawa ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Room Temperature Ionic Liquids ◽  
Bromide Anion ◽  
Structure And Dynamics

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

scholarly journals Cat-CrNP as new material with catalytic properties for 2-chloro-2-propen-1-ol and ethylene oligomerizations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacek Malinowski ◽  
Dagmara Jacewicz ◽  
Artur Sikorski ◽  
Mariusz Urbaniak ◽  
Przemysław Rybiński ◽  
...  
Keyword(s):  
Complex Compound ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Organometallic Compounds ◽  
Ethylene Oligomerization ◽  
High Catalytic Activity ◽  
New Material ◽  
Activity Requirement ◽  
Olefin Oligomerization ◽  
Xrd Method

AbstractThe contemporary search for new catalysts for olefin oligomerization and polymerization is based on the study of coordinating compounds and/or organometallic compounds as post-metallocene catalysts. However known catalysts are suffered by many flaws, among others unsatisfactory activity, requirement of high pressure or instability at high temperatures. In this paper, we present a new catalyst i.e. the crystalline complex compound possesing high catalytic activity in the oligomerization of olefins, such as 2-chloro-2-propen-1-ol and ethylene under very mild conditions (room temperature, 0.12 bar for ethylene oligomerization, atmospheric pressure for 2-chloro-2-propen-1-ol oligomerization). New material—Cat-CrNP ([nitrilotriacetato-1,10-phenanthroline]chromium(III) tetrahydrate) has been obtained as crystalline form of the nitrilotriacetate complex compound of chromium(III) with 1,10-phenanthroline and characterized in terms of its crystal structure by the XRD method and by multi-analytical investigations towards its physicochemical propeties The yield of catalytic oligomerization over Cat-CrNP reached to 213.92 g · mmol−1 · h−1· bar−1 and 3232 g · mmol−1 · h−1 · bar−1 for the 2-chloro-2-propen-1-ol and ethylene, respectively. Furthemore, the synthesis of Cat-CrNP is cheap, easy to perform and solvents used during preparation are environmentally friendly.

Defect Structure of MEV Si Implantation in GaAs

1988 ◽  
Vol 126 ◽  
Author(s):  
S.-Tong Lee ◽  
G. Braunstein ◽  
Samuel Chen
Keyword(s):  
Free Surface ◽  
Defect Structure ◽  
Room Temperature ◽  
Surface Region ◽  
Peak Position ◽  
Lattice Disorder ◽  
Depth Profiles ◽  
Trim Calculation ◽  
Good Agreement

ABSTRACTThe defect and atomic profiles for MeV implantation of Si in GaAs were investigated using He++ channeling, TEM, and SIMS. Doses of 1–10 × 1015Si/cm2 at 1–3 MeV were used. MeV implantation at room temperature rendered only a small amount of lattice disorder in GaAs. Upon annealing at 400°C for 1 h or 800°C for 30 a, we observed a ‘defect-free’ surface region (- 1 μ for 3 MeV implant). Below this region, extensive secondary defects were formed in a band which was 0.7 μ wide and centered at 2 μ for 3 MeV implant. These defects were mostly dislocations lying in the [111] plane. SIMS depth profiles of Si implants showed the Si peak to be very close to the peak position of the defects. The experimental profiles of Si were compared to the TRIM calculation; generally good agreement existed among the peak positions.

Analysis of Thermal Variation of Length and Refractive Index of Lead Fluoride to Study its Optical Properties

1989 ◽  
Vol 172 ◽  
Author(s):  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day
Keyword(s):  
Refractive Index ◽  
Room Temperature ◽  
Linear Thermal Expansion ◽  
Small Variation ◽  
Published Data ◽  
Thermal Variation ◽  
Lead Fluoride ◽  
Superionic Phase Transition ◽  
Lorenz Relation ◽  
Good Agreement

AbstractLinear thermal expansion and refractive index variation have been measured in lead fluoride with a laser interferometer as a function of temperature. Data has been analyzed using the Lorentz-Lorenz relation. Molecular polarizability, band gap, variation of refractive index with density, and strain-polarizability parameter have been studied as a function of temperature. They exhibit a small variation with temperature except near the superionic phase transition where the variation appears to be more pronounced. The results are in good agreement with the published data near room temperature.

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