Metal/metallic nitrosyls preparation

Reductive nitrosylation, transition metal nitrosyl complexes, 34 296-297 ReFejSj cluster, 38 41-43 self-assembly system, 38 41-42 Refining, of actinide metals, see Actinide, metals, purification Refractory compounds heat treatment of solids, 17 105-110 crystal growth, 17 105, 106 decomposition, 17 107,-110 spheroidization, 17 106, 107 preparation of, using radio-frequency plasma, 17 99-102... 

The well authenticated binary metal nitrosyl Co(NO)3, is prepared as shown in equation (4).S0... 

Dichlorodinitrosylmolybdenum and tungsten have been prepared by the reaction of the appropriate hexacarbonyl with nitrosyl chloride in dichloromethane.1 The corresponding dibromo derivatives have been prepared by a similar reaction with nitrosyl bromide.2 These are the only synthetic routes to these compounds they are rapid (3 hours) and convenient. The corresponding chromium compounds are unknown. This method is a general route to transition-metal nitrosyl halide... 

PF3-containing transition metal nitrosyl complexes such as [Co(NO)(PF3)3] and [Fe(NO)2(PF3)2] were first prepared by Kruck and Lang (206, 207) by reduction of dimeric nitrosyl halide complexes with copper in the presence of PF3 (method A). 

Until recently most of the mechanistic studies on nitrosation have been concerned with N-nitrosation reactions of amines, including the diazotisation reactions of primary amines. Now, work has been extended to include both O- and S-nitrosation, so that comparisons can be made. Mechanistic studies have also been extended in recent years to include reactions of nitrogen oxides, nitrosamines, alkyl nitrites, thionitrites and transition metal nitrosyl complexes. Many of these reactions have been used preparatively for a long time, but little has been known about their detailed reaction mechanisms. 

Few successful reactions are known by which an organometallic nitrosyl product has been formed from the condensation of mononuclear metal nitrosyl complexes. The unique cluster (Tj -C5H5)3Mn3(NO)4 (39), which contains the only i3-NO known (7) (40), is prepared using photochemical or thermal (41) decarbonylation of (Tj -C5H5)2Mn2(CO)2(NO)2 [Eq. (25)]. The use of the redox condensation of a nitrosyl carbonylmetallate with a neutral metal carbonyl cluster to produce a nitrosyl cluster has... 

Fig. 1. Reaction vessel, immersion well, and filtration assembly for the photochemical preparation of metal nitrosyls. A = Teflon needle stopcock, 0-5 mm B = O-ring connector, tube i.d. 75 mm F = fritted glass disk, o.d. 15 mm L = mercury lamp O = O-ring connector, tube i.d. 15 mm P = Pyrex tubing, o.d, 80 mm, length 10 in. Q = water-cooled quartz immersion well, o.d. 65 mm V = Viton O ring.

One of the most prominent features of ruthenium chemistry is that the metal forms numerous compounds containing the (RuNO) + fragment. Furthermore, the metal-nitrosyl fragment has in general been of interest to many because of the potential 7r-acceptor ability of NO and its possible existence as NO+, NO , or NO. Explicit details of how to synthesize the ruthenium-NO complexes are virtually nonexistent, and procedures, when available, are laborious. Here we give the preparative descriptions for such compounds by newly developed methods which are explicit and convenient. The information is also valuable in view of the cost of ruthenium. 

Although a large number of transition metal nitrosyl compounds have been prepared 208), Mn3(77--Cp)3(NO)4 described in Section II, D is the only characterized nitrosyl cluster 130). King has isolated a compound for which he postulated the formula Fe2(NO)2[S2C2(CF3)2]2, but the mass spectra indicated the formulation Fe3(NO)4S[S2C2(CF3)2]2 240). 

Nitric oxide is used as an intermediate in the manufacmre of nitric acid, in the preparation of metal nitrosyls, in bleaching of rayon, and in incandescent lamps. It is produced by heating air at high temperamres. 

Many methods have been used to prepare NO complexes. The reactions of transition metal complexes with gaseous NO or solutions of the dissolved gas have been used to form NO complexes. One example of such a reaction to form, a homoleptic nitrosyl complex is shown in Equation 4.30. Alternatively, the reactions of metal complexes with nitrosonium salts form metal-nitrosyl complexes. (Note Alcohol solvents should be used with caution, because they convert NO " to alkyl nitrites. In addition, tetrahydrofuran should not be used as solvent because it can be polymerized by NO". ) Two examples of such processes are shown in Equations 4.31 and 4.32. A range of organic nitroso compounds release "NO" under appropriate conditions and have been used to introduce NO into transition metal complexes. The generation of a metal-nitrosyl complex from F3CNO is shown in Equation 4.33. ° Inorganic nitrites have also been used to prepare NO complexes, ° as shown in Equation 4.34. ... 

The general topic of transition metal nitrosyl chemistry has been ably treated by Johnson and McCleverty (48), and this more restricted survey owes much to that review. Here we shall briefly consider the nature of the metal-ligand link in organometallic nitrosyls, the preparative chemistry of the main classes of compounds, and the physical data which have been derived for them, laying particular stress on the more recent developments. 

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