Metal 1:1 Chromium Complexes Containing

Chromium Complexes Containing Sulfonic Acid Groups. The production of premetallized complex dyes began in 1912, when R. Bohn of BASF synthesized 1 1 chromium complexes and BA SF and CIBA introduced ranges of sulfonic acid containing 1 1 chromium complex azo dyes. No metal other than chromium is suitable for this class of dyes. 

This reaction occurs in benzene in 40% yield. The structures of the isostructural series V2(CO)s(PMe2)2, Cr2(CO)s(PMe2)2 and Mn2(CO)s(PMe)2 show, as expected by electron counting, that the vanadium complex contains a V=V bond, the chromium complex contains a Cr-Cr bond, and the manganese complex does not contain a metal-metal bond. 

Elschenbroich C, Bzetschneider-Huriey A, Huriey J et al. (1995) Metal complexes of benzene derivatives. 45. Dinuclear bis(.eta,6-aiene)vanadium and chromium complexes containing 1,3-disilacyclobutane as a spacer. An EPR study of intermetaUic communication. Inoig Chem 34 743-745... 

The question of the compatibility of metals and alloys with carbon and carbonaceous gases has assumed considerable importance in connection with the development of the gas-cooled nuclear reactor in which graphite is used as a moderator and a constituent of the fuel element, and carbon dioxide as the coolant. Tests of up to 1 000 h on a series of metals and nickel-containing alloys under pressure contact with graphite at 1 010°C" showed that only copper was more resistant than nickel to diffusion of carbon and that the high-nickel alloys were superior to those of lower nickel content. The more complex nickel-chromium alloys containing titanium, niobium and aluminium were better than the basic nickel-chromium materials. 

In a bidentate ligand system, three molecules of a dye containing either a terminal salicylic acid unit (as in 5.2) or an o-nitrosonaphthol residue are able to chelate simultaneously with a trivalent metal ion of CN6, such as chromium (III) or iron(III), to form a 1 3 metal-dye complex (as in 5.8). Historically, the most important bidentate ligand system was alizarin (5.1). It has been suggested that both hydroxy groups and the keto group in the peri position are all involved with the metal atom in the chelation mechanism. 

In an interesting study, phthalocyanine complexes containing four anthraquinone nuclei (5.34) were synthesised and evaluated as potential vat dyes and pigments [18]. Anthraquinone-1,2-dicarbonitrile or the corresponding dicarboxylic anhydride was reacted with a transition-metal salt, namely vanadium, chromium, iron, cobalt, nickel, copper, tin, platinum or lead (Scheme 5.6). Substituted analogues were also prepared from amino, chloro or nitro derivatives of anthraquinone-l,2-dicarboxylic anhydride. 

Symmetrical premetallised 1 2 metal-dye complexes of unsulphonated monoazo structures with aluminium (5.57) or trivalent iron (5.58) have been patented recently for use as solvent dyes [36]. They contain a polar methoxypropylaminosulphone grouping in each diazo component and are marketed as alkylamine salts. It remains to be seen, however, whether a full colour gamut of bright aluminium and iron complex dyes can be discovered with light fastness performance equivalent to that of currently available chromium and cobalt complex dyes. 

Although the preparative chemistry of (vinylketene)cobalt(I) complexes is relatively limited in the literature, the methods used include all the major procedures that have been more widely exploited in the analogous chromium and iron systems. There are many similarities between the intermediates involved in the synthesis of vinylketene complexes of iron, chromium, and cobalt, but as the metal is varied the complexes containing analogous ligands often exhibit significant differences in stability and reactivity (see Sections II and VI). Comparison of such species has often been an important aim of the research in this area. The (vinylketene)cobalt(I) complexes have also been shown to be synthetically useful precursors to a variety of naphthols, 2-furanones, ce-pyrones, phenols,6,22,95 >8, y-unsaturated esters,51 and furans.51,96a... 

The solvolysis of hexaaquachromium(HI) in DMSO proceeds via the series of complexes [Cr(DMS0)n(H20)6 ]3+ (n = 1 to 6).945,946 The anation and solvolysis of several chromium(III) complexes in DMSO have been studied 947,948 in general the reactions proceed by /d mechanisms. A direct electrochemical synthesis of [Cr(DMSO)6][BF4]3 has been reported.949 A comprehensive review of metal ion complexation by DMSO contains an extensive section on chromium(III).950... 

MORDANT. A substance capable uf binding a dye to a textile liber. The mordant forms an insoluble lake in the liber, the color depending on the metal of the mordant. The most itnponanL mordants are trivaleni chromium complexes, metallic hydroxides, tannic acid. etc. Mordants are used with acid dyes, basic dyes, direct dyes, and sulfur dyes. Prcmetallized dyes contain chromium in the dye molecule. A mordant dye is a dye requiring use of a mordant 10 be effective. See also Dyes. 

The silicon-metal doubly bonded compounds can further react to yield desired derivatives. Recently, vinyl magnesium bromide was reported to react with chloro complexes containing chromium or iron double bonds to silicon, to yield the l-metalla-2-sila-l,3-diene compounds (115, equation 34), which can potentially be used to functionalize silicon polymers in a desired fashion121. 

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