The 2003 CSC Pure or Applied Inorganic Chemistry Award Lecture Adventures in stable radical chemistry

2004 ◽  
Vol 82 (7) ◽  
pp. 1119-1127 ◽  
Author(s):  
Robin G Hicks

Stable radicals are of intense fundamental interest because they challenge conventional bonding paradigms, and they find a wide range of uses ranging from organic and polymer synthesis to biological and medicinal applications to materials science. Yet the directed synthesis and study of stable radicals for either fundamental or applied purposes are rarely pursued strategies. This Award Lecture describes my research group's efforts in exploratory and targeted research focusing on stable radical design.Key words: stable radicals, verdazyls, molecular magnetism.

2021 ◽  
pp. 2102011
Author(s):  
Mengyao Tang ◽  
Qiaonan Zhu ◽  
Pengfei Hu ◽  
Li Jiang ◽  
Rongyang Liu ◽  
...  

2019 ◽  
Vol 92 ◽  
pp. 01005
Author(s):  
Georgios Birmpilis ◽  
Reza Ahmadi-Naghadeh ◽  
Jelke Dijkstra

X-ray scattering is a promising non-invasive technique to study evolving nano- and micromechanics in clays. This study discusses the experimental considerations and a successful method to enable X-ray scattering to study clay samples at two extreme stages of consolidation. It is shown that the proposed sample environment comprising flat capillaries with a hydrophobic coating can be used for a wide range of voids ratios ranging from a clay suspension to consolidated clay samples, that are cut from larger specimens of reconstituted or natural clay. The initial X-ray scattering results using a laboratory instrument indicate that valuable information on, in principal evolving, clay fabric can be measured. Features such as characteristic distance between structural units and particle orientations are obtained for a slurry and a consolidated sample of kaolinite. Combined with other promising measurement techniques from Materials Science the proposed method will help advance the contemporary understanding on the behaviour of dense colloidal systems of clay, as it does not require detrimental sample preparation


1992 ◽  
Vol 277 ◽  
Author(s):  
Geoffrey A. Ozin ◽  
Carol L. Bowes ◽  
Mark R. Steele

ABSTRACTVarious MOCVD (metal-organic chemical vapour deposition) type precursors and their self-assembled semiconductor nanocluster products [1] have been investigated in zeolite Y hosts. From analysis of in situ observations (FTIR, UV-vis reflectance, Mössbauer, MAS-NMR) of the reaction sequences and structural features of the precursors and products (EXAFS and Rietveld refinement of powder XRD data) the zeolite is viewed as providing a macrospheroidal, multidendate coordination environment towards encapsulated guests. By thinking about the α- and β-cages of the zeolite Y host effectively as a zeolate ligand composed of interconnected aluminosilicate “crown ether-like” building blocks, the materials chemist is able to better understand and exploit the reactivity and coordination properties of the zeolite internal surface for the anchoring and self-assembly of a wide range of encapsulated guests. This approach helps with the design of synthetic strategies for creating novel guest-host inclusion compounds having possible applications in areas of materials science such as nonlinear optics, quantum electronics, and size/shape selective catalysis.


2010 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
David Pennicard ◽  
Heinz Graafsma ◽  
Michael Lohmann

The new synchrotron light source PETRA-III produced its first beam last year. The extremely high brilliance of PETRA-III and the large energy range of many of its beamlines make it useful for a wide range of experiments, particularly in materials science. The detectors at PETRA-III will need to meet several requirements, such as operation across a wide dynamic range, high-speed readout and good quantum efficiency even at high photon energies. PETRA-III beamlines with lower photon energies will typically be equipped with photon-counting silicon detectors for two-dimensional detection and silicon drift detectors for spectroscopy and higher-energy beamlines will use scintillators coupled to cameras or photomultiplier tubes. Longer-term developments include ‘high-Z’ semiconductors for detecting high-energy X-rays, photon-counting readout chips with smaller pixels and higher frame rates and pixellated avalanche photodiodes for time-resolved experiments.


2021 ◽  
Author(s):  
Patrick M. Woodward ◽  
Pavel Karen ◽  
John S. O. Evans ◽  
Thomas Vogt

This comprehensive textbook provides a modern, self-contained treatment for upper undergraduate and graduate level students. It emphasizes the links between structure, defects, bonding, and properties throughout, and provides an integrated treatment of a wide range of materials, including crystalline, amorphous, organic and nano- materials. Boxes on synthesis methods, characterization tools, and technological applications distil specific examples and support student understanding of materials and their design. The first six chapters cover the fundamentals of extended solids, while later chapters explore a specific property or class of material, building a coherent framework for students to master core concepts with confidence, and for instructors to easily tailor the coverage to fit their own single semester course. With mathematical details given only where they strengthen understanding, 400 original figures and over 330 problems for hands-on learning, this accessible textbook is ideal for courses in chemistry and materials science.


MRS Bulletin ◽  
2003 ◽  
Vol 28 (12) ◽  
pp. 913-917 ◽  
Author(s):  
Dieter Richter ◽  
Dan A. Neumann

AbstractKnowledge of the dynamic dimension of materials is an extremely important ingredient for understanding their properties. Neutron scattering is uniquely capable of revealing aspects of the atomic and molecular geometry of motions over a wide range of time scales. To illustrate this fact, we give a number of examples from different areas of materials science. We discuss the diffusion of hydrogen in protonic conductors; the hydration of portland cement; and aspects of the molecular rheology of polymers, emphasizing in particular the effect of branching. All of these experiments have added important basic information to the understanding of the respective systems. With the advent of the new megawatt neutron spallation sources, the role of neutron scattering in revealing the dynamical properties of materials is expected to increase substantially.


MRS Bulletin ◽  
2005 ◽  
Vol 30 (8) ◽  
pp. 581-586 ◽  
Author(s):  
Robert W. Lashway

AbstractThe articles in this issue of MRS Bulletin highlight the enormous potential of fuel cells for generating electricity using multiple fuels and crossing a wide range of applications. Fuel cells convert chemical energy directly into electrical energy, and as a powergeneration module, they can be viewed as a continuously operating battery.They take in air (or pure oxygen, for aerospace or undersea applications) and hydrocarbon or hydrogen fuel to produce direct current at various outputs. The electrical output can be converted and then connected to motors to generate much cleaner and more fuelefficient power than is possible from internal combustion engines, even when combined with electrical generators in today's hybrid engines. The commercialization of these fuel cell technologies is contingent upon additional advances in materials science that will suit the aggressive electrochemical environment of fuel cells (i.e., both reducing an oxidizing) and provide ionic and electrical conductance for thousands of hours of operation.


2021 ◽  
Vol 25 ◽  
Author(s):  
Saima malik ◽  
Aditya G. Lavekar ◽  
Bimal Krishna Banik

: The radical was first come into existence in 1900 by Gomberg, where the triphenylmethane radical was explored. Thus, even to date, two centuries have seen radical chemistry as the methodology of preference in organic synthesis. Due to the fascinating nature of the radical-mediated cyclization reactions, it always caught the eye of organic chemists for the synthesis of novel organic compounds with diverse stereochemistry. Moreover, the development of radical methods further proves beneficial for the synthesis by providing atom- and step-economical methods to complex molecules. Among these, where radical chemistry has been employed, the use of tin-based radical annulation is the most common and widely used field for the synthesis of a wide range of organic reactions with medicinal importance. In this review, we compiled recent tin-mediated radical cyclization reactions toward the synthesis of molecules of biological significance.


Synlett ◽  
2021 ◽  
Author(s):  
Oliver Dumele ◽  
Niklas Grabicki

AbstractStrained aromatic macrocycles based on cycloparaphenylenes (CPPs) are the shortest repeating units of armchair single-walled carbon nanotubes. Since the development of several new synthetic methodologies for accessing these structures, their properties have been extensively studied. Besides the fundamental interest in these novel molecular scaffolds, their application in the field of materials science is an ongoing topic of research. Most of the reported CPP-type macrocycles display strong binding toward fullerenes, due to the perfect match between the convex and concave π-surfaces of fullerenes and CPPs, respectively. Highly functionalized CPP derivatives capable of supramolecular binding with other molecules are rarely reported. The synthesis of highly functionalized [n]cyclo-2,7-pyrenylenes leads to CPP-type macrocycles with a defined cavity capable of binding non-fullerene guests with high association constants.


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