Some new diphosphine-bridged nickel carbonyl and cyclopentadienyl compounds

1969 ◽  
Vol 47 (8) ◽  
pp. 1429-1431 ◽  
Author(s):  
A. J. Carty ◽  
A. Efraty ◽  
T. W. Ng
Keyword(s):  
Room Temperature ◽  
Direct Reaction ◽  
Nickel Carbonyl ◽  
Mild Conditions ◽  
Nickel Phosphine

The binuclear diphosphine bridged monocarbonyl compound [Ni(CO)]2(DPPA)3 has been obtained by reaction of Ni(CO)4 with bis(diphenylphosphino)acetylene (DPPA) under mild conditions and by displacement of π-cyclopentadienyl groups from [π-C5H5Ni(CO)]2 at room temperature. The latter reaction suggests a possible route to other monocarbonyl nickel phosphine compounds not available by direct reaction of Ni(CO)4 with phosphines. The preparation and characterization of the binuclear compounds [Ni(CO)2]2(DPPA)2, [Ni(CO)3]2(DPPA), and (π-C5H5NiI)2(DPPA) are also described.

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

scholarly journals Characterization of Chitosan Extracted from Fish Scales of the Colombian Endemic Species Prochilodus magdalenae as a Novel Source for Antibacterial Starch-Based Films

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2079
Author(s):  
Carlos Molina-Ramírez ◽  
Paulina Mazo ◽  
Robin Zuluaga ◽  
Piedad Gañán ◽  
Juan Álvarez-Caballero
Keyword(s):  
Molecular Weight ◽  
Antibacterial Activity ◽  
Room Temperature ◽  
Low Molecular Weight ◽  
Fish Scales ◽  
Molecular Weight Characteristic ◽  
Mild Conditions ◽  
And Staphylococcus Aureus ◽  
Positive Results

Scales of Prochilodus magdalenae, a Colombian endemic fish species, were used to obtain chitosan for application as an antibacterial agent integrated into starch-based films. Analysis of its composition during the demineralization and deproteinization process indicated that minerals and protein were both removed successfully. At this point, mild conditions for the deacetylation process were employed, namely, 2, 4, and 6 wt.% NaOH at room temperature for 16 h. Chitosan processed under 2 wt.% NaOH had low molecular weight, with the lowest value of 107.18 ± 24.99 kDa, which was closely related to its antibacterial activity. Finally, this chitosan was integrated into a banana starch-based film, and its antibacterial activity was assayed in Escherichia coli and Staphylococcus aureus cultures, with positive results in the former culture, especially due to the low-molecular-weight characteristic of chitosan.

scholarly journals Bio-Based Solvents and Gasoline Components from Renewable 2,3-Butanediol and 1,2-Propanediol: Synthesis and Characterization

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1723 ◽  
Author(s):  
Vadim Samoilov ◽  
Denis Ni ◽  
Arina Goncharova ◽  
Danil Zarezin ◽  
Mariia Kniazeva ◽  
...  
Keyword(s):  
High Selectivity ◽  
Calorific Value ◽  
Direct Reaction ◽  
Green Solvents ◽  
Glycol Ethers ◽  
Mild Conditions ◽  
Antoine Equation ◽  
Boiling Points ◽  
Aliphatic Ketones

In this study approaches for chemical conversions of the renewable compounds 1,2-propanediol (1,2-PD) and 2,3-butanediol (2,3-BD) that yield the corresponding cyclic ketals and glycol ethers have been investigated experimentally. The characterization of the obtained products as potential green solvents and gasoline components is discussed. Cyclic ketals have been obtained by the direct reaction of the diols with lower aliphatic ketones (1,2-PD + acetone → 2,2,4-trimethyl-1,3-dioxolane (TMD) and 2,3-BD + butanone-2 → 2-ethyl-2,4,5-trimethyl-1,3-dioxolane (ETMD)), for which the ΔH0r, ΔS0r and ΔG0r values have been estimated experimentally. The monoethers of diols could be obtained through either hydrogenolysis of the pure ketals or from the ketone and the diol via reductive alkylation. In the both reactions, the cyclic ketals (TMD and ETMD) have been hydrogenated in nearly quantitative yields to the corresponding isopropoxypropanols (IPP) and 3-sec-butoxy-2-butanol (SBB) under mild conditions (T = 120–140 °C, p(H2) = 40 bar) with high selectivity (>93%). Four products (TMD, ETMD, IPP and SBB) have been characterized as far as their physical properties are concerned (density, melting/boiling points, viscosity, calorific value, evaporation rate, Antoine equation coefficients), as well as their solvent ones (Kamlet-Taft solvatochromic parameters, miscibility, and polymer solubilization). In the investigation of gasoline blending properties, TMD, ETMD, IPP and SBB have shown remarkable antiknock performance with blending antiknock indices of 95.2, 92.7, 99.2 and 99.7 points, respectively.

Preparation and Characterization of Platinum Nanorods Using Ascorbic Acid as the Reducing Agent

2013 ◽  
Vol 774-776 ◽  
pp. 577-580 ◽  
Author(s):  
Ming Yang ◽  
Juan Juan Xia
Keyword(s):  
Ascorbic Acid ◽  
Room Temperature ◽  
Average Length ◽  
Decisive Role ◽  
Photoelectron Spectra ◽  
Direct Reaction ◽  
X Ray ◽  
Platinum Particles ◽  
Scanning Electron

Nanorods of platinum with an average length of 500-1000nm have been prepared by a simple reaction between H2PtCl6·6H2O and ascorbic acid in the presence of deionized gelatin at room temperature. Gelatin played a decisive role as an inhibitor of the direct reaction of ascorbic acid with H2PtCl6·6H2O and coagulation of the growing platinum in producing the nanorods. In the absence of gelatin, we can only obtain irregular large platinum particles. The products were characterized by X-ray powder diffraction, scanning electron microscope and X-ray photoelectron spectra.

scholarly journals Solid state synthesis and characterization of pyrazole and pyrazolates complexes of Cobalt (II) ions

2020 ◽  
Vol 12 (1) ◽  
pp. 145-151
Author(s):  
T. Abubakar ◽  
M. A. Kurawa ◽  
S. Isyaku ◽  
E.C. Ozoro
Keyword(s):  
Solid State ◽  
Mole Fraction ◽  
Room Temperature ◽  
Decomposition Temperature ◽  
Infrared Analysis ◽  
Direct Reaction ◽  
Conductivity Measurements ◽  
Pyridine Nitrogen ◽  
Metal Ligand

There were two ways used to synthesized cobalt (II) complexes of pyrazole by solid state. The first route involved direct reaction of the appropriate cobalt (II) acetate with pyrazole and pyrazolium chloride to form bispyrazole cobalt(II) salts, [(HPz)2CoCl2]. This was further ground in the second route with a two equivalents of a base (KOH) to make polymeric cobalt (II) pyrazolate [Co(Pz)2]. In all the synthesis above the ratio of ligand to cobalt (II) acetate was 2:1. All the cobalt (II) complexes were found to be of different colour from the starting materials and were characterized using solubility test, which showed that the complexes have poor solubility in most of the solvents used except in dimethylsulfoxide where they were soluble and the molar conductivity measurements of the complexes have low values (ranging from 6.44-6.45Ω-1cm2mol-1) which showed that they are non-electrolytes. The decomposition temperature showed that all the complexes have relatively low decomposition temperatures (93°C- 95°C). Characterization of the complexes via infrared analysis confirmed the coordination of metal with the ligand through pyridine-nitrogen and deprotonated-nitrogen in the range of 435.93cm-1 Co-N bonds and 406.99cm-1Co –N (for the route A and B respectively). The magnetic susceptibility measurements were carried out at room temperature and the effective magnetic moment values for all the complexes further confirmed complexation of the metal (II) ions with the ligand and also indicates that the cobalt (II) complexes are paramagnetic. The plot of absorbance against mole fraction in each case gives a curve with maximum absorbance corresponding to the ligand mole fraction used in calculating the number of coordinated ligands and 1:2 metal-ligand ratios were obtained in all the complexes. Keywords:  Mechanochemical, Pyrazole, Pyrazolate, Grinding, Mechanochemical Elimination.

scholarly journals H/D Exchange Under Mild Conditions in Arenes and Unactivated Alkanes with C6D6 and D2O Using Rigid, Electron-rich Iridium PCP Pincer Complexes

2020 ◽  
Author(s):  
Joel D. Smith ◽  
George Durrant ◽  
Daniel Ess ◽  
Warren Piers
Keyword(s):  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Room Temperature ◽  
Pincer Complexes ◽  
Synthesis And Characterization ◽  
Hydrogen Isotope Exchange ◽  
Mild Conditions ◽  
Highly Active ◽  
Pcp Pincer

<div>The synthesis and characterization of an iridium polyhydride complex (Ir-H4)</div><div>supported by an electron-rich PCP framework is described. This complex readily loses molecular</div><div>hydrogen allowing for rapid room temperature hydrogen isotope exchange (HIE) at the hydridic</div><div>positions and the α-C-H site of the ligand with deuterated solvents such as benzene-d6, toluene-d8</div><div>and THF-d8. The removal of 1-2 equivalents of molecular H2 forms unsaturated iridium carbene</div><div>trihydride (Ir-H3) or monohydride (Ir-H) compounds that are able to create further unsaturation</div><div>by reversibly transferring a hydride to the ligand carbene carbon. These species are highly active</div><div>hydrogen isotope exchange (HIE) catalysts using C6D6 or D2O as deuterium sources for the</div><div>deuteration of a variety of substrates. By modifying conditions to influence the Ir-Hn speciation,</div><div>deuteration levels can range from near exhaustive to selective only for sterically accessible sites.</div><div>Preparative level deuterations of select substrates were performed allowing for procurement of</div><div>>95% deuterated compounds in excellent isolated yields; the catalyst can be regenerated by</div><div>treatment of residues with H2 and is still active for further reactions.</div>

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

SuFEx Activation with Ca(NTf2)2: A Unified Strategy to Access Sulfamides, Sulfamates and Sulfonamides from S(VI) Fluorides

2020 ◽  
Author(s):  
Subham Mahapatra ◽  
Cristian P. Woroch ◽  
Todd W. Butler ◽  
Sabrina N. Carneiro ◽  
Sabrina C. Kwan ◽  
...  
Keyword(s):  
Room Temperature ◽  
Medicinal Chemistry ◽  
Mild Conditions ◽  
Broad Array

<p><br></p> <p>A method to activate sulfamoyl fluorides, fluorosulfates, and sulfonyl fluorides with calcium triflimide, and DABCO for SuFEx with amines is described. The reaction was applied to a diverse set of sulfamides, sulfamates, and sulfonamides at room temperature under mild conditions. Additionally, we highlight the application of this transformation to parallel medicinal chemistry to generate a broad array of nitrogen-based S(VI) compounds. </p>

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