Showing papers by "Malcolm L. H. Green published in 1965"
TL;DR: In this paper, the physical properties of the metal-hydrogen bond are discussed, and the role of transition metal hydrides in homogeneous catalysis has also been discussed.
Abstract: Publisher Summary This chapter discusses those discrete complexes of hydride that contain one or more hydrogen atoms bonded directly to a transition metal by an essentially covalent, two-electron bond. It is convenient and to some extent chemically significant to classify hydrides according to the nature of the other ligands attached to the metal. Accordingly, the following classes are recognized: (1) Complex hydrides with tertiary phosphines and related ligands, (2) Carbonyl hydrides: (a) mononuclear, (b) polynuclear, (3) π-Cyclopentadienylcarbonyl hydrides, (4) Bis(π-cyclopentadienyl) hydrides, (5) Cyanide hydrides, (6) Hydride complexes containing nitrogen ligands, and (7) “Pure” hydrides: complexes with hydride as the sole ligand. The chapter highlights the physical properties of the metal-hydrogen bond. The hydrogen atoms in metal-hydride complexes occupy accepted coordination positions, and the most reliable determinations indicate M–H distances compatible with an essentially normal covalent bond. It appears that the high field shift of M-hydrogens is largest for first-row transition metals; the complexes of metals of the second and third transition series show shifts that are about 25% less than those of the lightest group members. The role of transition metal hydrides in homogeneous catalysis has also been discussed in the chapter.
71 citations
TL;DR: The field of allyl metal complexes was brought into focus following studies by Jonassen and coworkers on the complex C 4 H 7 Co(CO) 3 as discussed by the authors, which is the only known π-allyl complex of transition metal.
Abstract: Publisher Summary This chapter reviews various allyl metal complexes. There are two main preparative routes to σ-allyl complexes, both of which involve standard methods for preparing metal–carbon σ bonds. Reaction of sodium metal carbonyls with allyl halides and addition of metal hydride complexes to conjugated dienes are also explained. A list of known σ–allyl complexes of transition metals has been provided. All the known compounds are yellow oils, which are insoluble in water, but very soluble in nonpolar solvents, such as petroleum ethers or benzene. Both the pure complexes and, especially, their solutions are oxidized by atmospheric oxygen, as are the closely related σ-alkyl metal complexes. The field of both σ- and π-allyl complexes was brought into focus following studies by Jonassen and coworkers on the complex C 4 H 7 Co(CO) 3. There are several general methods available for preparing π-allyl or the more simply substituted π-allylic complexes; these methods are explained along with examples. Allyl complexes form a part of the series of π organometallic complexes classified by the number of electrons the ligand formally contributes to the ligand–metal bond. Using these examples, and in the light of the rare gas formalism and consideration of other known organometallic complexes, possible complexes of the first-row transition metals, which are not known but which might be expected to exist, are formulated.
64 citations
TL;DR: In this article, the reaction between the lithiated rhenium complex and methyl iodide affords a complex which, on the basis of analyses, nuclear magnetic resonance and infra-red data, is formulated as π-cyclopentadienyldimethylrhenium methylcyclopentadiene.
17 citations