As the aromaticity of metallabenzenes and heterometallabenzenes has been
reviewed quite recently by us ; herein, we shall only discuss the most relevant
issues associated with this controversial topic. From an experimental point of
Author: L. James Wright
Publisher: John Wiley & Sons
The only comprehensive book covering of advances in metallabenzene chemistry—written by the leading experts in the field Metallabenzenes: An Expert View provides comprehensive coverage of all aspects of metallabenzene chemistry, including syntheses, reactions, physical properties, and theoretical treatments of metallabenzenes. Fused ring metallabenzenes, heterometallabenzenes, and metallabenzenes that are p-bound to other metal fragments are also discussed in depth. Although benzene itself was discovered in 1825, it wasn’t until 1982 that the first metallabenzene was isolated. Since then, interest in these compounds has built steadily, and metallabenzene chemistry is now a flourishing sub discipline in its own right. A diverse range of synthetic approaches to these compounds have been devised, and new developments and discoveries have appeared regularly over the past several decades. Yet, until now, no books devoted to this fascinating and important class of chemical compounds have been available to researchers and students. This bookfills that gap in the literature with a comprehensive review of recent advances in metallabenzene chemistry theory and applications. Featuring contributions by an international group of experts in the field, each chapter summarizes important recent research in and significant contributions to various aspects of metallabenzene chemistry. Provides academics, researchers and graduate students with a comprehensive review of advances in metallabenzene research Covers fused-ring metallabenzenes—including metallanaphthalenes, metallabenzofurans, and metallabenzothiophenes—as well as p-bound heterometallabenzenes and metallabenzenes Reviews the latest computational studies that have led to the theoretical understanding of metallabenzenes Includes critical discussions of metallabenzene aromaticity, an area rarely covered by computational experts Metallabenzenes: An Expert View is an important working resource for those working in organometallic chemistry, aromaticity, coordination chemistry, theoretical chemistry, catalysis and materials science. It is also an excellent text for graduate-level courses in those areas.
17-21,94,95 Metallabenzene Stability and Reactivity . A. Cyclopentadienyl
Complex Formation . One common reaction of metallabenzenes is the formation
of cyclopentadienyl ( Cp ) complexes.42 This was demonstrated by Jones and ...
Theoretical studies on bonding in platinum boryl and metallabenzene complexes
and mechanisms of ruthenium ... which is the highest occupied molecular orbital (
HOMO ) in many metallabenzenes , has antibonding interactions between the ...
The chemistry of these novel compounds was explored as well. An underlying theme throughout the work was determining how the properties and chemistry of the metallacyclic species compared to their organic analogues.
Author: Benjamin Frogley
Metalla-analogues of archetypical aromatic compounds have been attracting a great deal of interest in recent years. Metallabenzenes, where a methine unit in benzene has been formally replaced by a transition metal and its ancillary ligands, are a well-studied example which fall into this class. However, examples where additional fused rings are attached to the metallabenzene core are scarce and the chemistry of these `fused-ring metallabenzenes' is only just beginning to be explored. The work described herein sought to contribute to our understanding of these intriguing compounds. The focus was directed to two key areas. Firstly, the chemistry of fused-ring metallabenzenes was explored. We were especially interested in how the ligand environment about the metal could influence the reactions on the metallacyclic rings and the ring substituents. Secondly, rational syntheses of new fusedring metallabenzenes were designed and executed. The chemistry of these novel compounds was explored as well. An underlying theme throughout the work was determining how the properties and chemistry of the metallacyclic species compared to their organic analogues. The introduction begins with a brief overview of aromaticity in general and how the properties of metallabenzenes and metallabenzenoids meet this classification. This moves on to a description of the reported synthetic routes to fused-ring metallabenzenes and the reactions which they undergo. Chapter 2 describes electrophilic aromatic substitution reactions of iridabenzofurans, the metalla-analogue of benzo[b]furan. These compounds contained only one ring substituent, making them ideally suited for this purpose. Halogenation, nitration and thiocyanogenation reactions were conducted, and it was determined that the regioselectivity and extent of the reactions were determined by the ancillary ligands on iridium, the formal charge of the complexes, and the nature of the electrophile. Several of the new compounds prepared by SEAr reactions were well-suited for further reactions and this formed the basis for Chapter 3. The nitration products from the previous chapter served as precursors to the first metallabenzene derivatives with primary amino substituents. These could then be used to prepare simple derivatives such as alkylamines, sulfonamides, amides, as well as more unusual imide derivatives. The ancillary ligands and formal charge were again found to be important in determining the stability and extent of the reactions. The rst metallabenzene derivatives containing a ring of saturated carbons was described in Chapter 4. These were prepared by an extension of the synthesis used to prepare the iridabenzofurans. The additional five- or six-membered fused-rings bestowed these tricyclic iridabenzenes with an interesting new dimension to their chemistry. Bromination and dehydrobromination of the five-membered rings led to new iridaindene derivatives, while the same reactions with sixmembered rings gave dihydroiridanaphthalene derivatives. A further dehydrogenation of one of these allowed a metallanaphthofuran to be obtained. Extending the new procedure even further allowed the first metallaanthracene to be synthesised and this is described in Chapter 5. The iridaanthracene is the next member of the metalla-analogues of linear polycyclic aromatic hydrocarbons, for which only metallanaphthalenes were previously known. Structurally, it has a number of features in common with anthracene including fused-ring planarity and bond length alternation. In reactions which parallel those of anthracene, the iridaanthracene forms Diels-Alder adducts with dienophiles and on oxidation forms an unprecedented fused-ring metallaanthraquinone.
Interestingly , metallabenzenes ( 17 and 21 ) and 1 - silanphthalene 18 were
found to undergo 1,2- and / or 1,4 - addition reactions depending on the
character of the reactants , while 2 - metallaaromatic systems 19 and 22 afforded
only 1,2 ...
When equation 30 was used to calculate the ASE , the estimated degree of
aromaticity in the heavier metallabenzenes relative to benzene was higher , i.e.
AE ( equation 30 ) 58-60 kcal mol - 1 for SigH6 , GerHo and 1,3,5 - Siz GezH6 ,
... but having one bridging in the solid.65 A rare example of a stable metallabenzene complex was synthesized in three ... to produce monosubstituted metallabenzenes [cyclic] [CH=C(Me)CH=C(Me)CH=Ir(PEt3)2L] (L = PMe3 132a,
Generally , these metallabenzenes are incorporated into transition - metal
complexes in which the metal center is part of the aromatic system and is
coordinated by o - donor ligands . Representative structures are shown in figure
2-5 such as ...
Updated to incorporate the latest developments and research, a practical scientific reference provides detailed explanations of chemical terms from all branches of the science, all enhanced with helpful illustrations. Original.
This widely acclaimed serial contains authoritative reviews that address all aspects of organometallic chemistry, a field that has expanded enormously since the publication of Volume 1 in 1964.
Author: Anthony F. Hill
Publisher: Academic Press
Almost all branches of chemistry and material science now interface with organometallic chemistry--the study of compounds containing carbon-metal bonds. This widely acclaimed serial contains authoritative reviews that address all aspects of organometallic chemistry, a field that has expanded enormously since the publication of Volume 1 in 1964. Contributions from leading authorities Informs and updates on all the latest developments in the field
22.214.171.124.1.2 Method 2: Synthesis of Platinabenzenes Bearing a η5-
Pentamethylcyclopentadienyl Ligand Metallabenzenes having aromaticity are
interesting compounds. A platinabenzene complex bearing a η5-
Publisher: Georg Thieme Verlag
The Science of Synthesis Editorial Board, together with the volume editors and authors, is constantly reviewing the whole field of synthetic organic chemistry as presented in Science of Synthesis and evaluating significant developments in synthetic methodology. Highlights of this volume of Knowledge Updates include chapters on the chemistry of platinum and iridium complexes, as well as the synthesis of triazoles, phthalazines, and quinazolines, heterosubstituted alkynes, nitrosoalkenes, and various haloalkane compounds.