Organometallisk kemi

This volume describes the latest advances and perspectives in hydrosilylation, with a focus on new organometallic catalysts and their mechanistic aspects. Hydrosilylation is the reaction of ¿SiH with carbon-carbon, carbon-heteroatom or heteroatom-heteroatom bonds and is the most fundamental and elegant method for laboratory and industrial synthesis of organosilicon molecular and macromolecular compounds. Yet these reactions do require a catalyst, for which initially homogeneous noble metal catalyst, mainly platinum, rhodium, iridium or ruthenium were used. However the high prices, metallic residues of these valuable catalysts as well as issues with product purification, did increase the interest in developing new catalysts. Noteworthy in this regard are the recently developed hydrosilylation reactions using catalysts based on earth-abundant transition metals (for example Mn, Fe, Co, Ni) and heterogeneous catalysts presented here. This volume of Topics in Organometallic Chemistry is written for scientists interested in silicon chemistry and its catalytic aspects, but can also be used as valuable handbook for postgraduate and advanced undergraduate students working with organometallic chemistry, catalysis as well as synthesis of fine chemicals.

This book describes the development of two kinds of continuous-flow transformation using heterogeneous catalysts, and explains how they can be applied in the multistep synthesis of active pharmaceutical ingredients. It demonstrates and proves that fine chemicals can be synthesized under continuous-flow conditions using heterogeneous catalysis alone. Importantly, the book also proposes a general concept and strategy for achieving multistep flow synthesis and developing heterogeneous catalysts, and shows that commercially available anion exchange resin can be used as a water-tolerant strong base catalyst for various types of continuous-flow aldol-type reaction. Reviewing the state of the art in heterogeneous catalysis in flow chemistry - a "e;hot topic"e; and rapidly developing area of organic synthesis - the book will provide readers with a deeper understanding of fine chemical flow synthesis and its future prospects. 

Chapters collected from "The Virtual Conference on Chemistry and its Applications (VCCA-2021) - Research and Innovations in Chemical Sciences: Paving the Way Forward". This conference was held in August 2021 and organized by the Computational Chemistry Group of the University of Mauritius. These peer-reviewed chapters offer insights into research on fundamental and applied chemistry with interdisciplinary subject matter.

This thesis describes the development of iron-catalyzed thienyl C¿H/C¿H coupling. This is applied to the synthesis of highly conjugated and electron-rich thiophene compounds of interest in materials science by utilization of low redox potential of iron in combination with a mild oxalate oxidant.Transition-metal-catalyzed C(sp2)¿H/C(sp2)¿H coupling has attracted much attention as one of the most straightforward methods to construct C(sp2)¿C(sp2) bonds. However, application of this ideal transformation to the synthesis of redox-sensitive pi-materials was hindered by the requirement of a strong oxidant for catalyst turnover. This limitation originates primarily from the large redox potential of conventional transition-metal catalysts such as palladium and rhodium. This thesis shows that the efficiency of C¿H activation was significantly improved by introduction of a new conjugated tridentate phosphine ligand, giving direct access to polymeric thiophene materials from simple thiophene monomers. Considering the importance of environmentally friendly organic synthesis in terms of UN Sustainable Development Goals, the reactions described herein highlight the potential of iron, the most abundant transition-metal on earth, for the direct synthesis of functional small molecules and polymers of importance in energy device applications.

This volume presents recent progress on 3d base metal catalyzed C-C cross coupling reactions. The contributions provide detailed discussions on the use of cheap metal catalysts such as Cr, Mn, Fe, Co, Ni, Cu, and Zn to construct Csp2-Csp2, Csp2-Csp3 and Csp3-Csp3 bonds with a variety of substrates. These non-noble metal catalyst have many advantages such as being inexpensive, having low toxicity and are environmentally benign. Therefore the use of cheap metal catalysts in organic synthesis has gained much attention in efforts to develop more sustainable synthetic green chemistry. Each chapter is written by international experts in the field and is a great resource for students, researchers and chemists working in industry to gain an overview on the latest developments.

This book presents recent advances in dinuclear complexes in which the metal-metal cooperative effect operates for obtaining substrate activation and high performance catalysts. Catalysis continues to be a fast expanding area to design efficient tools in synthesis and in industrial chemistry. It allows performing syntheses with short reaction times, atom economy, reduced consumption of energy and loss of reagents, and low level of wastes. Dinuclear complexes are known to be more efficient than the mononuclear analogues for the reaction rates and the selectivities. This book analyses the latest research, focusing on the key concepts, in building and using these dinuclear complexes. The book is aimed at researchers, graduate students and chemists at all levels in academia and industry.

This book presents experimental work conducted on the International Space Station (ISS) in order to characterize metals and alloys in the liquid state. The internationally recognized authors present and discuss experiments performed in microgravity that enabled the study of the relevant volume and surface related properties free of the restrictions of a gravity-based environment. The collection serves also as a handbook of space experiments using electromagnetic levitation techniques. A summary of recent results provides an overview of the wealth of space experiment data, which will ignite further research activities and inspire academics and industrial research departments for their continuous development. 

This book focuses on the development of novel functionalized organoboron compounds and those synthetic methods. High degrees of chemo-, regio-, and stereoselectivities of the borylation reactions are attained through catalyst design and optimization. Furthermore, the selectivity-determining mechanisms are analyzed with state-of-the-art DFT and other computational methods.In this book, the author synthesizes some multi-substituted alkenyl and allylic boronates via borylation reactions using a copper(I)/diboron catalyst system. Those compounds contain novel densely substituted and distorted structures, which have not been accessed by other methods. The high stereoselectivities are achieved by the optimization of the catalyst, especially the ligand. Some new ligands are also developed in this book. Furthermore, the derivatization of the borylation products is demonstrated to access the sterically demanding complex molecules. Also, the author performs computational analysis toreveal how the catalyst controls the selectivities. The deep insight into the reaction mechanism provides guides for rational catalyst design for not only copper(I) catalysis but also other transition metal catalysis. Thus, the content should be of interest to academic and industrial scientists in a wide range of areas.

Tracing the life of a giant in inorganic chemistry and key trends in his science, Boranes and Beyond follows Hawthorne from his mid-American origins to the halls of Harvard and UCLA and back again. It naturally details the accomplishments in his lab. This book is a fascinating mixture of science and autobiography. Prof. Hawthorne won the Priestley Medal, the highest award of the American Chemical Society, for his pioneering work in elucidating the chemistry of boron. He has chronicled in this book the developments in his lab which ultimately led to this achievement.Not content to rest on his laurels, after retiring from UCLA Prof. Hawthorne explored the use of boron in biomedicine and directed the International Institute of Nano & Molecular Medicine at the University of Missouri-Columbia.

A celebrated international bestseller that exposes the ticking time-bomb underneath our new technological order.The resources race is on. Powering our digital lives and green technologies are some of the Earth's most precious metals - but they are running out. And what will happen when they do? The green-tech revolution will reduce our reliance on nuclear power, coal, and oil, but by breaking free of fossil fuels, we are setting ourselves up for a new dependence - on rare metals like cobalt, gold, and palladium. These are essential to electric vehicles, wind turbines, and solar panels, as well as our smartphones, computers, tablets, and other technologies. But we know very little about how rare metals are mined and traded, or their environmental, economic, and geopolitical costs - until now.

Aldol Reactions provides a comprehensive up-to-date overview of aldol reactions including application of different metal enolates; catalytic aldol additions catalyzed by different Lewis acids and Lewis bases; enantioselective direct aldol additions; antibodies and enzyme catalyzed aldol additions and the recent aggressive development of organocatalyzed aldol additions. The power of each method is demonstrated by several applications in total synthesis of natural products. The pros and cons of these methodologies with regard to stereoselectivity, regioselectivity and application in total synthesis of natural products are discussed. Great importance is set to the diverse possibilities of the manual of aldol reaction to install required configurations in complicated natural product synthesis.

Doctoral Thesis / Dissertation from the year 2018 in the subject Engineering - Metal Engineering / Metal Processing / Metal Structure, , language: English, abstract: The thesis has been divided into several chapters dealing with extensive literature and experimental studies. It focuses on the geological aspects (i.e. correlation with other mineral/ rock in the type area, lithological alignment, availability of different types of fauna and flora and the geomorphological attributes.Second part of the thesis is based on the experimental aspects of Banded Hematite Jasper. It includes different methods of characterisation and its implications on the development of new processes for beneficiation. These experimental techniques also help in understanding the interlocking pattern, % of ore & gangue, extent of liberation and magnetic behaviour of the ore. The experimental section also describes the mechanical and metallurgical behaviour of the ore (Bond Work Index, Vickers Hardness Test). Those parameters help in knowing inter-molecular structure, presence of hydroxyl ion and up to some extent it reveals the quantitative nature of the ore. The experimental part also describes the kinetic behaviour of the ore with coal (i.e. extent of metallisation, factors responsible for reducibility and the activation energy) required for the ore. The experimental section describes the temperature of reduction of the ore with coke oven gas. In this section focus has been given to evolve a correlation between the grain size and the residence time with varying temperature.

Carbon-carbon and carbon-heteroatom bond-forming reactions are the backbone of synthetic organic chemistry. Scientists are constantly developing and improving these techniques in order to maximize the diversity of synthetically available molecules. These techniques must be developed in a sustainable manner in order to limit their environmental impact. This book highlights green bond forming reactions for bioactive scaffolds.

Master's Thesis from the year 2009 in the subject Chemistry - Materials Chemistry, , course: M.Phil, language: English, abstract: This thesis is about Substituted Nickel Phthalocyanines and their preparation. Currently intensive research work is going on in producing phthalocyanine compounds, which have been useful for applications, such as important industrial dyes and pigments since their early syntheses at the beginning of last century. They have been employed as charge carriers in photocopiers and laser printers, as well as materials for optical storage in recent years. Many potential applications were expected for these molecular materials which have a high thermal and chemical stability, for instance as potential industrial catalysts, solar cell functioning materials , gas sensors , nonlinear optical limiting devices , as power leads and as molecular switches in nanotechnology, photodynamic therapy agents, antiscrapie treatments, antimycotic materials, antimicrobial agents, as corrosion inhibitors, as photoconductors, electrical conductors, photosensitizers, photovoltaic materials and as colorants for cyano toners.Except for few derivatives, soluble phthalocyanine complexes were prepared for dyes and colors, which were found to be impure. Use of pure phthalocyanines and their derivatives are very important in order to exploit the full potential of the coloring effects, thermal stability, photoconductivity, semi conducting, catalytic and various other physico chemical properties. The solubility of phthalocyanines can be increased either by changing the number and nature of the substitutents or by changing the central metal ion. Ligation of the central metal ion will also enhance the solubility. In the present investigation, it was planned to synthesize various metal phthalocyanines containing different substitutents at particular positions, so that symmetrically tetra substituted derivatives will be prepared and their structural investigations will be carried out by using various physicochemical techniques. Hence it was found desirable to synthesize and characterize tetra anilido 2,9,16,23 substituted Ni Phthalocyanine in order to exploit the spectral, thermal stability and electrochemical characteristics and like other properties and hence the present study has been undertaken. This study may give greater insight on the properties of the unique character of Ni Phthalocyanine Derivatives and their potential applications.

Organometallic Ion Chemistry features eight chapters, written by acknowledged authorities, covering the gas-phase chemistry of organometallic ions. Topics covered include: periodic trends in gas-phase thermochemistry of transition metal-ligand systems; ab initio calculations to determine electronic structure, geometric structure, and thermochemistry of metal-containing systems; electronic state effects on metal ion reactivity; organometallic ion photochemistry; applications of gas-phase electron transfer equilibria in organometallic redox thermochemistry. Also included are state of the art mass spectrometric instrumentation used in such studies. Finally, the book features - for the first time in one place - a comprehensive list (containing over 1500 entries) of metal ion-ligand bond energies, obtained from theory and experiment. An invaluable reference source for ion chemists, organometallic chemists and surface chemists, at both expert and graduate student levels.

Document from the year 2018 in the subject Engineering - Metal Engineering / Metal Processing / Metal Structure, grade: A, Srinivas School of Engineering (Institute of Technology), language: English, abstract: Red mud emerges as the major waste material during production of alumina from bauxite by the Bayer¿s process. It comprises of oxides of iron, titanium, aluminum and silica along with some other minor constituents. Based on economics as well as environmental related issues, enormous efforts have been directed worldwide towards red mud management issues for example of utilization, storage and disposal. Different avenues of red mud utilization are more or less known but none of them have so far proved to be economically viable or commercially feasible. It is generally agreed that resistance to wear of MMCs is created by reinforcement and also the wear properties are improved remarkably by introducing hard intermetallic compound into the aluminium matrix. The reinforcing materials are generally SiC, Al2O3, TiB2 etc and are costly. The present research work has been undertaken with an objective to explore the use of red mud as a reinforcing material as a low cost option. This is due to the fact that red mud alone contains all these reinforcement elements and is plentifully available. Composites are prepared by liquid melt metallurgy techniques using vortex method. Castings are cut, turned and shaped into the required size to prepare the specimens for evaluation of the mechanical properties like hardness, tensile and wear properties.

Proceedings of the NATO Advanced Research Workshop, Debrecen, Hungary, August 29--September 1, 1994

Aldol Reactions provides a comprehensive up-to-date overview of aldol reactions including:Application of different metal enolatesCatalytic aldol additions catalyzed by different Lewis acids and Lewis basesEnantioselective direct aldol additionsAntibodies and enzyme catalyzed aldol additionsThe recent aggressive development of organocatalyzed aldol additions. The power of each method is demonstrated by several applications in total synthesis of natural products. The pros and cons of these methodologies with regard to stereoselectivity, regioselectivity and application in total synthesis of natural products are discussed. Great importance is set to the diverse possibilities of the manual of aldol reaction to install required configurations in complicated natural product synthesis.