Nitroso compounds metal complexes

Acid Dyes. These water-soluble anionic dyes ate appHed to nylon, wool, sUk, and modified acryHcs. They ate also used to some extent for paper, leather, food, and cosmetics. The original members of this class aU had one or mote sulfonic or catboxyHc acid groups in thein molecules. This characteristic probably gave the class its name. Chemically, the acid dyes consist of azo (including preformed metal complexes), anthraquiaone, and ttiaryHnethane compounds with a few azHie, xanthene, ketone imine, nitro, nitroso, and quHiophthalone compounds. 

Complexes of the lanthanides with amine oxides, nitroso compounds, and nitroxide radicals fall under this category. However, only the complexes with the amine oxides have received wide attention. Four comprehensive reviews have appeared on the complexes of amine oxides with various metal ions 142-145). Only a few complexes of the lanthanides have been quoted in these reviews. 

Metal complexes of o-hydroxynitroso compounds are principally of historical interest since the iron complex of l-nitroso-2-naphthol (Pigment Green B Cl 10006), which still finds commercial application as a green pigment, is the oldest fully synthetic metal complex dyestuff, dating back... 

No N nuclear quadrupole resonance (NQR) studies have been reported for transition metal nitrosyl complexes. This technique is expected to show interesting differences between linear and bent nitro-syls since the values of the quadrupole coupling constant and the asymmetry parameter depend on the relative populations of the nitrogen s,p, py, andpz orbitals. NQR spectroscopy has been used to study organic and inorganic nitroso compounds, and it is found that both... 

Several other nitroso compounds have been investigated by PES. The nitrosyl halides, Hal-NO, are basic inorganic compounds. Of particular inteest for organic chemists are nitrosamines, R2N—NO, and nitrites, RO—NO. The NO group occurs as a ligand in transition metal complexes and PE spectra of complexes of chromium, manganese, iron, cobalt and nickel have been measured. ... 

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. ... 

Sulphonium ylides react with a variety of miscellaneous electrophilic reagents. Barney has reported that dimethylsulphoniumcyclopenta-dienylide (3) will form complexes with a variety of metal salts, such as Hgl2, ZnCU, and AgNOa, with some co-ordination occurring with the ring and some with the sulphur. Dimethylsulphoniumphenacylide reacted with isopropyl nitrite to afford the bromo-keto-oxime (52), probably the result of ylide attack on nitrogen, isomerization of the nitroso-compounds to... 

It has been considered that a coordinated nitrene may give the same reaction and work in our group has shown that this is indeed possible in at least one case [260] (see also Chapter 5). However, it should be also noted that we now know that most reactions of nitro- and nitroso compounds with a metal complex occur through an intermediate electron transfer to the organic compound vide supra). Thus the formation of the radical anion of o-nitro- and/or o-nitrosobiphenyl should be considered as probable during the reaction. The reactivity of such radicals is virtually unknown and it cannot be excluded that these species, and not a nitrene intermediate, are responsible for the carbazole formation. The validity of carbazole formation as an indication for nitrene intermediates has been questioned very early [261]. It was shown that other reactions (including oxidation of 2-amino-biphenyl) can afford carbazole. Thus the results of this test should be taken with caution. 

Other relevant material is contained in reviews on homogeneous catalysis of organic reactions by transition metal complexes, highly reduced metal carbonyl complexes, phosphine complexes of the early transition metal complexes and the lanthanoids, metal NMR spectra of transition metal organometallic systems, the coordination chemistry of C-Nitroso-compounds, mono-Cp halide complexes of the d- and/-block, and organometallic chemistry in the gas phase. o... 

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