Bonding organometallic chemistry

Undoubtedly the most important development in the cr-bonded organometallic chemistry of this Group is the development of a new synthesis of cationic... 

There is also a considerable chemistry, especially of platinum, in the +4 state, some of these being among the most stable cr-bonded organometallics known. The prototype compound PtMe3I was reported as long ago as 1907 (Pope and Peachey) and certain of its features have become clear particularly as a result of studies since the 1960s. 

Multiple bonds between transition metals and bare main group elements links between inorganic solid state chemistry and organometallic chemistry. W. A. Herrmann, Angew. Chem., Int. Ed. Engl., 1986, 25,56 (115). 

Low oxidation states - An important characteristic of transition metal chemistry is the formation of compounds with low (often zero or negative) oxidation states. This has little parallel outside the transition elements. Such complexes are frequently associated with ligands like carbon monoxide or alkenes. Compounds analogous to Fe(CO)s, [Ni(cod)2] (cod = 1,4-cyclooctadiene) or [Pt(PPh3]3] are very rarely encountered outside the transition-metal block. The study of the low oxidation compounds is included within organometallic chemistry. We comment about the nature of the bonding in such compounds in Chapter 6. 

One family of porphyrin complexes that will be treated in the review, even though they do not contain metal-carbon bonds, are metalloporphyrin hydride and dihydrogen complexes. As in classical organometallic chemistry, hydride complexes play key roles in some reactions involving porphyrins, and the discovery of dihydrogen complexes and their relationship to metal hydrides has been an important advance in the last decade. 

Abstract The use of A-heterocyclic carbene (NHC) complexes as homogeneous catalysts in addition reactions across carbon-carbon double and triple bonds and carbon-heteroatom double bonds is described. The discussion is focused on the description of the catalytic systems, their current mechanistic understanding and occasionally the relevant organometallic chemistry. The reaction types covered include hydrogenation, transfer hydrogenation, hydrosilylation, hydroboration and diboration, hydroamination, hydrothiolation, hydration, hydroarylation, allylic substitution, addition, chloroesterification and chloroacylation. 

Frankland discovered the fundamental principle of valency—the combining power of atoms to form compounds. He gave the chemical bond its name and popularized the notation we use today for writing chemical formulas. He codiscovered helium, helped found synthetic organic and structural chemistry, and was the father of organometallic chemistry. He was also the first person to thoroughly analyze the gases from different types of coal and—dieters take note—the first to measure the calories in food. 

Phosphorus ligands bound to cobalt are met more broadly in the parallel Comprehensive Organometallic Chemistry series, but some representative examples not also including Co—C bonded species are presented here. 

The Ni—P bond is one of the basic motifs in Ni-based catalysis and Ni organometallic chemistry. The earlier work on phosphine-nickel complexes has been reviewed.636 The complex [Ni(dppm)Cl2] with the Ph2PCH2PPh2 (dppm) ligand is square planar. Complexes of formula... 

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