Mononuclear Carbonyl Derivatives

1 Mononuclear Carbonyl Derivatives. - Two further reports on the chemistry of highly reduced carbonylate anions have appeared. [V(C0)s] and [VH(C0)5] have been characterised by C, V and H n.m.r. spectroscopies, and the corresponding tantalum carbonylate 

Papers on the identification, magnetic properties and substitution behaviour of several metal carbonyl radicals have been published. E.s.r. measurements on matrix isolated carbonyls M(C0)f, (M = Cu or Ag, n = 1 or 3 and M = Au, n = 1) have been used to infer structural and bonding data. Spectra of Ag(C0)3 recorded under differing conditions have been interpreted in terms of two 

The transient infrared absorption spectra of the co-ordinatively unsaturated Cr(CO) species [x = 5, 4, 3 and 2), generated via excimer laser photolysis of gas phase Cr(C0)6, have been described. The results indicate that the gas-phase structures of these species are similar to those observed in condensed-phase experiments. Reactions, including some kinetic data, have been reported on several of these species. Several photolyses experiments have been carried out on Fe(C0)5, and rate constants for the reaction of Fe(C0)p (n = 4, 3 or 2) with CO determined. The generation and some reac- 

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In this report we will discuss only transition metal carbonyl clusters as catalysts, or catalyst precursors. However, the reader must be aware that the family of compounds able to catalyze reactions 1-3 is mainly composed of mononuclear carbonyl derivatives. Moreover, even when the starting compound is a cluster, the true active species is often mononuclear (or at least of lower nuclearity) and only little, indirect evidence supports the participation of the cluster in the main catalytic cycle. 

Group VIIA (Mn, Tc. Re). A number of mononuclear manganese carbonyl derivatives have been y- irradiated and examined by e.s.r. spectroscopy. The motivation behind much of this effort was the search for the elusive radical Mn(CO)s. The e.s.r. spectrum of this species is now firmly (35-37) established (Figure 4), although there is still some suggestion that the true "naked Mn(CO)s has yet to be observed (37). 

Finally, the surface-mediated synthesis of ruthenium carbonyl complexes has also been used to prepare supported ruthenium particles. Using silica as a reaction medium and conventional salts, apart from Ru3(CO)i2, mononuclear Ru(CO)j, and high nuclearity carbonyl-derived species can be obtained by CO reductive carbonylation [127, 128]. This opens new routes to preparing tailored supported ruthenium particles. 

I. by Reaction with Mononuclear Transition- or Inner TransKlon-Metal Carbonyl Derivatives. 

Reaction with Mononuclear Metal Carbonyl Derivatives... 

A series of mononuclear phenyl derivatives of platinum(II) containing bidentate phosphine ligands (P—P) undergoes carbonylation to the corresponding benzoyls ... 

The first mononuclear carbonyl compound of cobalt, iron or manganese known was the pentacarbonyl complex [Fe(CO)5] " with a trigonal-bipyramidal ligand field (see Fig. 2). Though related electroneutral species of cobalt and manganese are not known due to a strict observance of the 18-electron-rule in these cases, the monoanionic manganese derivative fMn(CO)5] has also been described as a trigonal-bipyramidal species. ... 

The mononuclear carbonyls of nickel and iron that are liquid at the ambient temperatures are extremely flammable. Their vapors present flashback fire hazard. They also form explosive mixtures with air. Also, most mononuclear carbonyls that are solids at ambient conditions are pyrophoric. These include the carbonyls of vanadium and tungsten. All carbonyl complexes are air sensitive. Some of them ignite on prolonged exposure to air or may catch fire when opened to air after long storage. The dimeric and trimeric derivatives, however, are less pyrophoric than the mononuclear complexes. All carbonyl metal complexes are susceptible to explode on heating. They react violently with strong oxidants. 

R. B. King, C. C. Frazier, R. M. Hanes, A. D. King Jr., Active homogeneous catalysts for the water gas shift reaction derived from the simple mononuclear carbonyls of iron, chromium, molybdenum, and tungsten, J. Am. Chem. Soc. 100 (1978) 2925-2927. 

Dodecacarbonyltriiron (Fe3(CO)j2) is an important starting material in preparative iron carbonyl chemistry. Many of its reactions lead to rupture of the iron triangle to give mononuclear iron carbonyl derivatives. Thus the major products from the reactions of Fe3(CO)i2 with tertiary phosphines R3P [e.g., R = C0H5... 

The yellow diamagnetic anions [CrgCCOXoSR]" (R = H, Me, Et,Ph) are formed on oxidation of aqueous Na2[Cr2(CO)io] by RSH, accompanied by the evolution of hydrogen, but when RSH is thio-p-cresol the mononuclear anion [Cr(CO)5SR] (R = CjH4Me) is isolated . The monomeric carbonyl derivatives M(CO)5SR" can be prepared by using the mercury thiolates only a small amount of the dimeric species is obtained . The... 

PHBu 2 the starting complex, yielding the mononuclear Pt(0) carbonyl derivative Pt(PHBu 2)2(CO)2, as an... 

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