A multifunctional divergent scaffold to access the formal syntheses of various sesquiterpenoids

2021 ◽  
Author(s):  
Vera P. Demertzidou ◽  
Maria Kourgiantaki ◽  
Alexandros L. Zografos
Keyword(s):  
Oxidation States ◽  
Unsaturated Lactone

A new divergent scaffold for the synthesis of various sesquiterpenoids in furan and α,β-unsaturated lactone oxidation states was developed through a novel, concise and scalable route.

MicroEXAFS study into the oxidation states of copper coloured Hispano-Moresque lustre decorations

2003 ◽  
Vol 104 ◽  
pp. 519-522 ◽  
Author(s):  
A. D. Smith ◽  
T. Pradell ◽  
J. Molera ◽  
M. Vendrell ◽  
M. A. Marcus ◽  
...  
Keyword(s):  
Oxidation States

Acceptorless amine dehydrogenation and transamination using Pd-doped layered double hydroxides

2018 ◽  
Author(s):  
Diana Ainembabazi ◽  
Nan An ◽  
Jinesh Manayil ◽  
Kare Wilson ◽  
Adam Lee ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Oxidation States ◽  
Secondary Amines ◽  
Primary Amines ◽  
Acid Dissolution ◽  
Oxidative Amination ◽  
Strong Function ◽  
Excellent Activity ◽  
High Yields ◽  
Double Hydroxides

<div> <p>The synthesis, characterization, and activity of Pd-doped layered double hydroxides (Pd-LDHs) for for acceptorless amine dehydrogenation is reported. These multifunctional catalysts comprise Brønsted basic and Lewis acidic surface sites that stabilize Pd species in 0, 2+, and 4+ oxidation states. Pd speciation and corresponding cataytic performance is a strong function of metal loading. Excellent activity is observed for the oxidative transamination of primary amines and acceptorless dehydrogenation of secondary amines to secondary imines using a low Pd loading (0.5 mol%), without the need for oxidants. N-heterocycles, such as indoline, 1,2,3,4-tetrahydroquinoline, and piperidine, are dehydrogenated to the corresponding aromatics with high yields. The relative yields of secondary imines are proportional to the calculated free energy of reaction, while yields for oxidative amination correlate with the electrophilicity of primary imine intermediates. Reversible amine dehydrogenation and imine hydrogenation determine the relative imine:amine selectivity. Poisoning tests evidence that Pd-LDHs operate heterogeneously, with negligible metal leaching; catalysts can be regenerated by acid dissolution and re-precipitation.</p> </div> <br>

Catalytic Fluorination of Boron Compounds at a Bismuth Redox Platform

2019 ◽  
Author(s):  
Oriol Planas ◽  
Feng Wang ◽  
Markus Leutzsch ◽  
Josep Cornella
Keyword(s):  
Transition Metal ◽  
Main Group ◽  
Group Element ◽  
Oxidation States ◽  
Boron Compounds ◽  
Main Text ◽  
Main Group Element ◽  
Rational Ligand Design ◽  
Supplementary Material

The ability of bismuth to maneuver between different oxidation states in a catalytic redox cycle, mimicking the canonical organometallic steps associated to a transition metal, is an elusive and unprecedented approach in the field of homogeneous catalysis. Herein we present a catalytic protocol based on bismuth, a benign and sustainable main-group element, capable of performing every organometallic step in the context of oxidative fluorination of boron compounds; a territory reserved to transition metals. A rational ligand design featuring hypervalent coordination together with a mechanistic understanding of the fundamental steps, permitted a catalytic fluorination protocol based on a Bi(III)/Bi(V) redox couple, which represents a unique example where a main-group element is capable of outperforming its transition metal counterparts.<br>A main text and supplementary material have been attached as pdf files containing all the methodology, techniques and characterization of the compounds reported.<br>

THE OXIDATION STATES OF IRON AND VOLATILE COMPOSITIONS OF EXPEDITION 352 GLASSES

2019 ◽  
Author(s):  
M. Brounce ◽  
◽  
Mark K. Reagan ◽  
Daniel A. Coulthard ◽  
Katherine A. Kelley ◽  
...  
Keyword(s):  
Oxidation States

scholarly journals 99mTc Labelling Strategies for the Development of Potential Nitroimidazolic Hypoxia Imaging Agents

Inorganics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 128 ◽  
Author(s):  
Giglio ◽  
Rey
Keyword(s):  
Rational Design ◽  
Biological Properties ◽  
Fine Tuning ◽  
Oxidation States ◽  
Hypoxia Imaging ◽  
Biological Target ◽  
99Mtc Radiopharmaceuticals ◽  
99Mtc Labelling

Technetium-99m has a rich coordination chemistry that offers many possibilities in terms of oxidation states and donor atom sets. Modifications in the structure of the technetium complexes could be very useful for fine tuning the physicochemical and biological properties of potential 99mTc radiopharmaceuticals. However, systematic study of the influence of the labelling strategy on the “in vitro” and “in vivo” behaviour is necessary for a rational design of radiopharmaceuticals. Herein we present a review of the influence of the Tc complexes’ molecular structure on the biodistribution and the interaction with the biological target of potential nitroimidazolic hypoxia imaging radiopharmaceuticals presented in the literature from 2010 to the present. Comparison with the gold standard [18F]Fluoromisonidazole (FMISO) is also presented.

ChemInform Abstract: Activation of Phosphorus by Group 14 Elements in Low Oxidation States.

ChemInform ◽  
2012 ◽  
Vol 43 (23) ◽  
pp. no-no
Author(s):  
Shabana Khan ◽  
Sakya S. Sen ◽  
Herbert W. Roesky
Keyword(s):  
Oxidation States ◽  
Group 14 ◽  
Group 14 Elements

scholarly journals Influence of Physicochemical Properties and Parent Material on Chromium Fractionation in Soils

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1073
Author(s):  
Claudia Campillo-Cora ◽  
Laura Rodríguez-González ◽  
Manuel Arias-Estévez ◽  
David Fernández-Calviño ◽  
Diego Soto-Gómez
Keyword(s):  
Physicochemical Properties ◽  
Contaminated Soils ◽  
Research Work ◽  
Parent Material ◽  
The Other ◽  
Oxidation States ◽  
Diethylenetriaminepentaacetic Acid ◽  
Remediation Strategies ◽  
Exchangeable Aluminum ◽  
Efficient Extraction

Chromium is an element that possess several oxidation states and can easily pass from one to another, so its behavior in soils is very complex. For this reason, determining its fate in the environment can be difficult. In this research work we tried to determine which factors affect the chromium fractionation in natural soils, conditioning chromium mobility. We paid special attention to the parent material. For this purpose, extraction experiments were carried out on spiked soils incubated for 50–60 days, using H2O, CaCl2 and diethylenetriaminepentaacetic acid (DTPA). The most efficient extraction rate in all soils was achieved using water, followed by CaCl2 and DTPA. We obtained models with an adjusted R2 of 0.8097, 0.8471 and 0.7509 for the H2O Cr, CaCl2 Cr and DTPA Cr respectively. All models were influenced by the amount of chromium added and the parent material: amphibolite and granite influenced the amount of H2O Cr extracted, and schist affected the other two fractions (CaCl2 and DTPA). Soil texture also played an important role in the chromium extraction, as well as the amounts of exchangeable aluminum and magnesium, and the bioavailable phosphorus. We concluded that it is possible to make relatively accurate predictions of the behavior of the different Cr fractions studied, so that optimized remediation strategies for chromium-contaminated soils can be designed on the basis of a physicochemical soil characterization.

Radially π-Extended Pyrrole-Fused Azacoronene: A Series of Crystal Structures of HPHAC with Various Oxidation States

2021 ◽  
Vol 86 (5) ◽  
pp. 4290-4295 ◽  
Author(s):  
Yoshiki Sasaki ◽  
Masayoshi Takase ◽  
Nagao Kobayashi ◽  
Shigeki Mori ◽  
Keishi Ohara ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Oxidation States
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