Carbonylate anions

Several 3-substituted 6-methylmercuriothiopyridazines and complexes of perfluoro-pyridazine with metal carbonyl anions have been prepared <67MI21200). 

Electron deficient carbon-carbon double bonds are resistant to attack by the electrophilic reagents of Section 5.05.4.2.2(t), and are usually converted to oxiranes by nucleophilic oxidants. The most widely used of these is the hydroperoxide ion (Scheme 79). Since epoxidation by hydroperoxide ion proceeds through an intermediate ct-carbonyl anion, the reaction of acyclic alkenes is not necessarily stereospecific (Scheme 80) (unlike the case of epoxidation with electrophilic agents (Section 5.05.4.2.2(f)) the stereochemical aspects of this and other epoxidations are reviewed at length in (B-73MI50500)). 

Very many derivatives of the carbonyls of Mn, l Tc and Re have been prepared since the parent carbonyls were first synthesized in 1949, 1961 and 1941 respectively among the more important are the carbonylate anions,... 

The treatment of iron carbonyls with aqueous or alcoholic alkali can, by varying the conditions, be used to produce a series of interconvertible carbonylate anions [HFe(CO)4] , [Fe(CO)4] ", [Fe2(CO)g]2-, [HFe3(CO) ]- and [Fe4(CO)i3]"". Of these the first has a distorted trigonal bipyrarmdal stracture with axial H, the second... 

Reduction of the pH of solutions of carbonylate anions yields a variety of protonated species and, from acid solutions, carbonyl hydrides such as the unstable, gaseous H2Fe(CO)4 and the polymeric liquids H2Fe2(CO)g and H2Fe3(CO)n are liberated. The use of ligand-replacement reactions to yield hydrides of higher nuclearity has already been noted. 

Thermolysis of binary carbonyls or of their partially substituted derivatives, either under vacuum or in solutions, has been used to produce carbonyls and carbonylate anions with an unparalleled range of structures (Fig. 25.11). The Ru chemistry, though less well developed, mostly parallels that of These compounds... 

Carbonyl hydrides and carbonylate anions are obtained by reducing neutral carbonyls, as mentioned above, and in addition to mononuclear metal anions, anionic species of very high nuclearity have been obtained, often by thermolysis. These are especially numerous for Rh and in certain Rh, Rh and Rhi5 anions have structures conveniently visualized either as polyhedra encapsulating further metal atoms, or alternatively as arrays of metal atoms forming portions of hexagonal close packed or body... 

Ni(CO)4] is readily oxidized by air and can be reduced by alkali metals in liquid ammonia or thf to yield a series of polynuclear carbonylate anion... 

Carbonylate anions are the most suitable starting material for the synthesis of silylmetal compounds. A prerequisite for the preparation of compounds with a formal M = Si double bond is the use of metallate dianions like Na2Fe(CO)4 (Collman s reagent) together with the respective dichlorosilanes [96]. 

It is known that Na2Fe(CO)4 can be silylated twice to form cri-[(H3C)3Si]2Fe(CO)4 [109]. Also the reaction of Na2Fe(CO)4 with 1.1-dichlorosilanes has been described and leads exclusively to the dimeric compounds [110, 111], In polar solvents the formation of dimers can be suppressed and monomeric base-stabilized compounds are obtained. A very elegant procedure is the in-situ generation of the carbonylate anions in solution by deprotonation of H2Fe(CO)4. 

As can be seen from Table 1, a whole set of compounds is available from the reaction of Eq. (5), which shows the high variability of both the substituents at silicon and the introduced metal. This method is only limited by the steric demand of the substituents. If the residues at the silicon are too bulky, no reaction according to Eq. (5) occurs. The method also allows the use of dinuclear carbonylate anions... 

Ion pairing effects on transition metal carbonyl anions. M. Y. Darensbourg, Prog. Inorg. Chem., 1985,33,221(138). 

Group-IIIB element-transition-metal compounds have been synthesized by means of anionic metal bases and halide-free group-IIIB compounds. The carbonylate anions of Mn and Re interact with BHj to give [HjBMfCOlj]", which are best isolated as the tetraalkylammonium or phosphonium salts ... 

Anions derived from transition-metal carbonyls (see also 8.3.3.1) react with Cu-or Ag-halogcn bonds e.g., triarsMBr (M = Cu, Ag) reacts with univalent or divalent carbonyl anions ... 

These reactions can be extended to many carbonyl derivatives that form carbonyl anions, such as those of V , Mo and W and Co, e.g., to form a cluster containing... 

Group IB-Transition- and Inner Transition-Metal Bonds 8.3.2.1. by Coupling Carbonyl Anions with Group-IB Monohalides... 

Whereas Cu and Ag form complexes with derivatives of transition-metal carbonyls in which the Cu or Ag are 4 coordinated in both the reactant and in the final product, many analogous Au complexes exhibit only 2 coordination. For example, the simple Au complex Ph3PAuCI reacts with transition-metal carbonyl anions in THF to give complexes with transition-metal to Au bonds, e.g. ... 

Anionic complexes containing two transition-metal to Au bonds can be formed by reacting R4N[AuX2l (R = Et, n-Bu X = Cl, Br) with carbonyl anions ... 

Anionic complexes also can be prepared from (THT)Au(C6F5) which reacts with carbonyl anions in CH2CI2 to give compounds with Au to transition-metal bonds ... 

Reaction of Carbonyl Anions with Derivatives of Group-IB. 

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