Chemistry of the Metal Carbonyls

The chemistry of the metal carbonyl hydrides and metal carbonylates remained the principal research topic for Hieber until the 1960s. He mentioned in his account [25], that it was a particular pleasure for him that in his laboratory the first hydrido carbonyl complexes of the manganese group, HMn(CO)5 and HRe(CO)5, were prepared by careful addition of concentrated phosphoric acid to solid samples of the sodium salts of the [M(CO)5] anions, giving the highly volatile hydrido derivatives in nearly quantitative yield [45, 46]. In contrast to HCo(CO)4 and its rhodium and iridium analogues, the pentacarbonyl hydrido compounds of manganese and rhenium are thermally remarkably stable, and in... 

Early in the development of the chemistry of the metal carbonyls and their derivatives, Cotton et al. (42) concluded that the number of infrared-active carbonyl stretching vibrations of a complex is determined by the idealized local symmetry of the terminal carbonyl groups. Although exceptions to this generalization are to be found (50, 60, 117, 134), its utility is now widespread (5, 17, 60, 116, 119). A consequence of this generalization is that the isomeric form of a complex may be determined... 

One of the major factors leading to the explosion, during the 1950s, in the chemistry of the metal carbonyls and other cluster compounds was the availability of instrumentation and experimental techniques to deal with these compounds. Many of the preparative techniques used in the formation of these compounds are often not difficult or sophisticated. The main problem was the identification of the compounds once they had been prepared. Even the basic analytical data could often be ambiguous when dealing with high molecular weight compounds, and the determi-... 

This section deals with the general chemistry of the metal carbonyls in triads. Unusually for this report there is a study of metal carbonyl complexes outside the transition metals. Xu et have provided details (IR spectra) of... 

This report deals with the chemistry of the metal carbonyls, metal carbonyl hydrides and metal carbonyl halides. Infrequently, complexes which are ostensibly outside the scope of this chapter are included for their importance and relevance to metal carbonyl chemistry. Ref.36 is a good example of this type of work. The general format remains similar to the 1991 report. Apart from the first and second sections, concerned with General Studies and Reviews and Theoretical and Spectroscopic Studies, the chapter is divided into sections for the transition metals of each group. A handful of references that appeared late in 1990 and were omitted from last year s report are included here. 

Cooke J, Green M, Stone FGA (1968) Chemistry of the metal carbonyls. Part XLII. Reactions between carbonylmetal anions and perfluoropyiidine, perfluoropyridazine, or cyanuric fluoride. J Chem Sos A 173-176... 

The chemistry of the metal carbonyls has been the subject of hundreds of research papers, most of them appearing in the last decade of renaissance of inorganic chemistry. Reviews have appeared on the metal carbonyls themselves (/, 2) and on such related topics as the anionic carbonyl-metallates (S), metal-olefin complexes (4,5), tricarbonyl(diene)iron species (6), perfluoroalkyl metal compounds (7), andTr-cyclopentadienyl andir-arene (S, 9) metal derivatives. ... 

Papers about the chemistry of the metal carbonyls are found in many journals, although the bulk of the research in this field is published in Organometallics, the Journal of Organometallic Chemistry, Inorganic Chemistry and Journal of the Chemical Society, Dalton Transactions. Workers would be well advised to have these publications available. 

It is important to realize that there is a great deal of overlap in the topics covered in this chapter. For example, the chemistry of metal carbonyls is intimately related to metal alkene complexes, because both types of ligands are soft bases and many complexes contain both carbonyl and alkene ligands. Also, both areas are closely associated with catalysis by complexes discussed in Chapter 22, because some of the best-known catalysts are metal carbonyls and they involve reactions of alkenes. Therefore, the separation of topics applied is certainly not a clear one. Catalysis by metal complexes embodies much of the chemistry of both metal carbonyls and metal alkene complexes. 

The rate of the methanol carbonylation reaction in the presence of iridium catalysts is very similar to that observed in the presence of rhodium catalysts under comparable conditions (29). This is perhaps initially surprising in view of the well-recognized greater nucleophilicity of iridium(I) complexes as compared to their rhodium(I) analogues. It can be seen from the above studies that the difference in the chemistry of the metals at the trivalent stage of the catalytic cycle serves to produce faster rates of alkyl migration with the rhodium system thus, overall the two metal catalysts give comparable rates. 

The electronic structures of the metal carbonyls have been investigated vigorously over the past few years because the interaction between CO and metals (76, 137) is essential for an understanding of both organometallic chemistry and CO chemisorption phenomena. There is continuing debate concerning the relative importance of o-donation from the carbon lone pair of carbon monoxide and back donation from metal d electrons into vacant rr ligand orbitals. The most frequently cited data in favor of n back donation are... 

In spite of some declining industrial interest, the last 5 years have seen an unusual academic interest in the catalytic properties of the metal carbonyls. This has been part of a wider surge of interest in the organometallic chemistry of the transition metals and its application to homogeneous catalysis. Reactions such as Ziegler polymerization, the Oxo reaction, and the Wacker process are but a few of the many reactions of unsaturated molecules catalyzed in the coordination sphere of transition metal complexes (20). These coordination catalyses have much in common, and the study of one is often pertinent to the study of the others. 

Because of the properties of the metal carbonyls, the experimental work required new techniques, such as the use of carbon monoxide under pressure in the laboratory, and the design of special apparatus. The results obtained always kept us in a state of excitement, thereby stimulating us to make further studies. Starting from modest beginnings it has been shown that the metal carbonyls in no way represent an isolated area of chemistry. Herein major results of our wrork have been summarized with no pretension to making a complete review. 

In recent years more and more emphasis has been laid on the chemistry of cyclopentadienyl metal carbonyls. In this field the reactions of cyclopentadienyl metal carbonyl halides with electron donors deserve special attention. Many of these reactions yield cations by replacement of halogen. In the following report, general procedures will be described by which substituted cyclopentadienyliron dicarbonyl cations of the type [C5H5Fe(CO)2L]+ can be prepared. 

Although nickel tetracarbonyl, iron pentacarbonyl, and diiron enneacarbonyl were already prepared in the 1890s, more than three decades passed before the chemistry of transition metal carbonyls took off. Undoubtedly, some parts of the chemical community had recognized that compounds such as Ni(CO)4 and Fe(CO)5 deserved special attention, in particular due to the use of Ni(CO)4 for the production of pure metallic nickel. However, since the structure of those compounds was unknown, transition metal carbonyls remained, more or less, a curiosity. 

Pauson s work on the structure and bonding of butadiene iron tricarbonyl launched a series of studies making the chemistry of olefin metal carbonyls an... 

Some aspects of the chemistry of polynuclear metal carbonyl compounds... 

The chemistry of transition metal carbonyls structural considerations... 

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