Metal carbonyl anions

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

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

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. ... 

A. Metal carbonyl anions/cyclopentadienylmetal carbonyl anions... 

It has been noted (Section II,B,1) that reactions between transition metal carbonyl anions and silicon halides often fail to produce species containing silicon-transition metal bonds, and that such failure has been ascribed to nucleophilic attack by carbonyl oxygen. It is therefore interesting that compounds containing Si—O—C—transition metal linkages have recently been isolated from such reactions [Eqs. (105) (R = Me, Ph) 183) and (106)... 

R. B. King Trans. N.Y. Acad. Metal carbonyl anions 6 ... 

Coordination compounds of d10, diamagnetic, Ir(-I) are very rare and are almost always synthesized via reduction of the parent Ir1 ds complex. The synthesis, characterization, and chemical properties of highly reduced metal carbonyl anions, including Ir, have been reviewed by Ellis in 1990.752... 

C02 and H2, presumably from the respective neutralizations of carbonate and of the metal carbonyl anions to give metal hydrides (e.g., H2Fe(C0)tf) which undergo reductive elimination of H2. 

Darensbourg, Marcetta York, Ion Pairing Effects on Metal Carbonyl Anions... 33 221... 

Thallium(i) salts have long been used in reactions with organic and organometallic halide complexes as a means of activating the halide by removal as insoluble T1X. However, the thallium ions proved not to be innocent bystanders, and numerous examples were reported in COMC (1995) where the metal-bound thallium complexes were formed. Deliberate reactions of thallium(i) and thallium(m) salts with metal carbonyl anions have yielded a variety of complexes of the form T1 MLJ3. In the past decade, new examples of metal carbonyl derivatives of thallium have been prepared (see Table 2). In addition, the propensity for Tl+ to form adducts with 16-electron noble metal complexes has been exploited. 

The first application of phase transfer catalysis in metal carbonyl chemistry was reported by Alper in 1977(23). It was found that metal carbonyl anions could be readily generated by this technique and used to prepare pi-allyl, cluster, and ortho-metalated complexes(24). 

Our efforts in this area of catalysis began in 1980. Our initial emphasis was on the preparation of supported phase transfer catalysts. We later became interested in the chemistry of anioni-cally activated alumina(25) and the reactivity of metal carbonyl anions prepared under these conditions. A brief description of our work in the preparation of these materials and their synthetic applications follows. 

A recent report( ) on the use of iron carbonyl and potassium carbonate in a similar carboxyalkylation scheme to prepare methyl phenylacetate prompted us to examine the use of carbonate on alumina in a similar manner. It was suggested that if the amount of free base was less than the amount of iron carbonyl than ether formation would not occur being that iron carbonyl was a better electrophile than benzyl halide. Under our conditions, the metal carbonyl anion... 

Carbonyl Complexes.—The first direct substitution of donor molecules into the co-ordination sphere of metal carbonyl anions has been reported for [M(C0)5] (M = Nb or Ta). Photolytically induced substitution of uni-and bi-dentate phosphines has been used to prepare (Et4N)[M(CO)5PPh3] and (Et4N)[M(CO)4(diphos)]. 

Group IVA Donor Ligands. The anomalous reactions of PhaSiCl with metal carbonyl anions are discussed on p. 180. Only in the case of [Co(CO)3PPh3] was the normal substitution product obtained. GeH3Br reacts with Na-[Co(CO)4] in ether to produce [H3GeCo(CO)4]. The trideuterio-compound has also been prepared and spectroscopic properties reported for both compounds. The preparation and attempted preparation of halogen-bridged Ge-M compounds is referred to on pp. 180 and 200. In the case of cobalt. 

Nucleophilicity, of metal carbonyl anions, 25 3 Nucleophilic substimtion reactions, in high-nuclearity carbonyl clusters, 30 187-202... 

The compound [PPN][Mn2(/i-PPh2)(CO)8] is an orange, air-stable solid. It is soluble in tetrahydrofuran, acetone, and chlorinated solvents, moderately soluble in alcohols and toluene and insoluble in water and hydrocarbon solvents. Solutions of [PPN][Mn2(ju-PPh2)(CO)8] are surprisingly stable as compared to most other transition metal carbonyl anions, decomposing only slowly (days) on exposure to air and/or moisture. The carbonyl IR spectrum of the anion in dichloromethane shows absorptions at 2037 (m), 1947 (s), 1941 (vs), 1914(w), 1888(m), and 1872(m).3... 

Rearrangements of clusters, i.e. changes of cluster shape and increase and decrease of the number of cluster metal atoms, have already been mentioned with pyrolysis reactions and heterometallic cluster synthesis in chapter 2.4. Furthermore, cluster rearrangements can occur under conditions which are similar to those used to form simple clusters, e.g. simple redox reactions interconvert four to fifteen atom rhodium clusters (12,14, 280). Hard-base-induced disproportionation reactions lead to many atom clusters of rhenium (17), ruthenium and osmium (233), iron (108), rhodium (22, 88, 277), and iridium (28). And the interaction of metal carbonyl anions and clusters produces bigger clusters of iron (102, 367), ruthenium, and osmium (249). 

Compounds containing niobium or tantalum in negative formal oxidation states -I and -III are mainly metal carbonyl anions. Although these are organometallic derivatives, the report of efficient procedures for the synthesis of [M(CO)6] since the review of Labinger8 merits mention, as it can be anticipated that these highly reduced and reactive species will be important precursors of a large variety of new coordination compounds and metal clusters. 

These were the first gold-metal-bonded complexes to be isolated and many examples are known.713 They are usually prepared by reaction of the appropriate metal carbonyl anion with a gold(I) complex [AuCIL], as in equation (77). Some typical examples are given in Table 13. 

In these complexes, the gold-metal bonds are apparently weak and polar and, in man cases, the metal carbonyl anion can be displaced by donor ligands (equation go)716 726>732,733 a well as by halogens and similar reagents.721... 

These complexes are related to those of Section 55.23.1, but have the added feature of Au Au bonding between the gold atoms. They are usually prepared from the metal carbonyl anion with [AuC1(PR3)] and some examples are given in Table 14. 

Metal carbonyl anions react with main group halides and oxides to yield a number of main-group transition-metal carbonyl complexes in good yields. These complexes serve as starting materials for a number of higher nuclearity cluster complexes. 

Analogously, reaction of group 7 metal carbonyl anions M(CO)5 (M = Mn, Re) with MeC(CFFI), gave cyclopropylcarbinyl complexes. Flowever, whereas rhenium produces the normal (/-metal bonded cyclopropylcarbinyl complex, the manganese complex furnished (cyclopropylacetyl)Mn(CO)5, where carbonyl insertion into the manganese-alkyl bond occurred (equation 56)114. 

Oligo- and polymethylene-bridged complexes can be prepared by reaction of metal carbonyl anions with w.w -dihaloalkanes. This method proved to be a simple entry to the iron series /j,-(CH2)j.][(t75-C5H5) Fe(CO)2]2 (x s 3) (283), but yielded quite different products in the case of Na[(T 5-C5H5)Mo(CO)3] (283) and Na[Mn(CO)s] (284). An alternative two-step synthesis of the iron compounds involves the preparation of the mononuclear w-haloalkyls LXM—(CH2)X—X, and a subsequent... 

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