Nitrosyl metal carbonyls

Nitrogen-donor complexes of metal carbonyls, 10, 115-186 Nitrosyl complexes, 7, 211-236 Nitrosyl metal carbonyls, 7, 216-222 8, 21-22, 223... 

Neutral and Cationic Ligands. Neutral and cationic ligands are used without change in name and are set off with enclosing marks. Water and ammonia, as neutral ligands, are called aqua and ammine, respectively. The groups NO and CO, when linked directly to a metal atom, are called nitrosyl and carbonyl, respectively. 

Carter, O. L., McPhail, A. T. Sim, G. A. (1967) Metal-carbonyl and metal-nitrosyl complexes. Part V. The crystal and molecular structure of the tricarbonylchromium derivative of methyl benzoate, J. Chem. Soc. A, 1619-1626. 

Carbonyl Nitric Oxides. Another group of metal-carbonyl complexes, worthy of investigation as CVD precursors, consists of the carbonyl nitric oxides. In these complexes, one (or more) CO group is replaced by NO. An example is cobalt nitrosyl tricarbonyl, CoNO(CO)3, which is a preferred precursor for the CVD of cobalt. It is a liquid with a boiling point of 78.6°C which decomposes at 66°C. It is prepared by passing NO through an aqueous solution of cobalt nitrate and potassium cyanide and potassium hydroxide. ... 

S. J. W. Price Decomposition of metal alkyls, aryls, carbonyls and nitrosyls, pp. 197-257 (156) see especially section 2, homogeneous decomposition of metal carbonyls, and section 3.1, homogeneous decomposition of metal alkyls and aryls (of Cu, Ag, Au). 

Nitrogen Groups in Metal Carbonyl and Related Complexes, 10, 115 Nitrosyls, 7, 211... 

The literature cited in this article covers references listed in chemical abstracts to the end of 1961 and in current chemical papers after that. A degree of selection has been exercised in omitting some references that are now of limited value. Although metal nitrosyls are included in the scope of this chapter, no kinetic data on their decomposition is available and they will not be considered further. The data on metal carbonyls is limited and will be dealt with in the first section. The decomposition of metal alkyls and aryls has been extensively investigated. These compounds will be discussed in groups based on the position of the central metal atom in the periodic table and, when warranted, a further subdivision will be made based on the attached organic radicals. 

The first attempts to interpret Werner s views on an electronic basis were made in 1923 by Nevil Vincent Sidgwick (1873—1952) and Thomas Martin Lowry (1874—1936).103 Sidgwick s initial concern was to explain Werner s coordination number in terms of the sizes of the sub-groups of electrons in the Bohr atom.104 He soon developed the attempt to systematize coordination numbers into his concept of the effective atomic number (EAN).105 He considered ligands to be Lewis bases which donated electrons (usually one pair per ligand) to the metal ion, which thus behaves as a Lewis acid. Ions tend to add electrons by this process until the EAN (the sum of the electrons on the metal ion plus the electrons donated by the ligand) of the next noble gas is achieved. Today the EAN rule is of little theoretical importance. Although a number of elements obey it, there are many important stable exceptions. Nevertheless, it is extremely useful as a predictive rule in one area of coordination chemistry, that of metal carbonyls and nitrosyls. 

It is possible that nitric oxide may be displaced from the metal centre prior to oxidation of the phosphine. Indeed, such a nitrosyl displacement in the complex CrCl(7t-Cp)(NO)2, leading to derivatives of the type CrCl(jr-Cp)NO(L), has been reported.118 However, such behaviour is rare (compared with CO displacements in metal carbonyls) and it seems likely that the above reduction takes place by an alternative process. 

Molecular Rearrangements in Polynuclear Transition Metal Complexes, 16, 319 Multiply Bonded Germanium Species, 21, 241 Nitrogen Groups in Metal Carbonyl and Related Complexes, 10, 115 Nitrosyls, 7, 211... 

With respect to the derivatives of metal carbonyls, the substituted metal carbonyls of the VIB Group (e.g., Mo(CO)apya), the halogenocar-bonyls of iron, ruthenium, iridium, and platinum, the hydridocarbonyls H2Fe(CO)4 and HCo(CO)4 discovered in 1931 and 1934, and the nitrosyl carbonyls FelCOj NOjg and Co(CO)3NO were the most important (/). The known anionic CO complexes were limited to [HFe(CO)J and [Co(CO)J-. For studies of substitution reactions of metal carbonyls at this time, work was almost totally limited to reactions involving the classical N ligands such as NH3, en, py, bipy, and phen. 

This type of metal carbonyl derivative has lately been the object of numerous investigations by many research groups with particular reference to metal-metal bond synthesis.3 In our laboratory the nitrosyl carbonyliron compounds R3MFe(NO)(CO)3 (M = Si, Ge, Sn, Pb R= C6H5, C4H9) have been prepared, and shown by infrared studies to have a trigonal bipyramidal structure with Cs symmetry (48). 

In this manner, the field of monohalide-metal nitric oxide complexes was developed, as well as the so-called nitroprussiates extensively studied by Nast and Proschel (104). Since these complexes do not contain CO groups as ligands a discussion of the noteworthy results falls outside the limits of this survey, although the field is closely related to the metal carbonyl nitrosyls. 

The substitution of a neutral ligand, including carbon monoxide, attached to a metal carbonyl complex by the nitrosyl cation, produces a cationic metal carbonyl nitrosyl. 

Metallocenes and related compounds for which mass spectral data have been reported are given in Tables I-XII, but in many cases only the molecular ion is reported. Metal carbonyls, nitrosyls and their derivatives, and fluorocarbon complexes are not discussed in this review, but Table XIX summarizes the compounds for which mass spectral data have been reported since Bruce s review (27). 

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