Chromium Chloride CrCl

Chloro Tetra Amine Chromium Chloride CrCl(NH3).(OHj)Cl. 

Chloro Purpureo Chromium Chloride CrCl(NH3)jClj Luteo Chromium Nitrate Cr(NH3),(NO,)8... 

Potassium dichromate (K2Cr20y Mai line-root), Chromium chloride (CrCl 6H20, Merck), Mitomycin C (Sigma C.C.) and MMS (methyl-methansulphonate, Merck) were used 1) the chromium compounds were solubilized in bidistilled water at the concentration of 10" M immediately before use .2) Mitomycin C was prepared at 100 yg/ml in bidistilled water then chemically reduced (5) and immediately used 3) MMS Img/ml was dissolved in bidistilled water and immediately used. All the compounds so dissolved were then brought to the desired dilution with nucleic acids to obtain a ratio Compound used/DNA Phosphorus = 1/1 in molar concentration. The samples were analyzed within one day. 

As an example of UV analysis of the interaction between DNA and the presumably genotoxic compounds we describe the experiments carried out with chromium chloride (CrCl 6H2O), a trivalent chromium compound, and potassium dichromate(K2Cr20y), an hexavalent chromium compound. 

Chlorides.—Two chlorides and one oxychloride of chromium are known. Chromoue chloride, CrCl, is a white solid, soluble with a blue color in H,0. Chromic chloride, (Cr,)Cl, forms large, red crystals, insoluble in H,0 when pure. 

A literature survey shows that the corresponding data are rather contradictory, as far as the solubilities of CrCk and CrCls are concerned, and as far as the Cr(II) / Cr deposition step is concerned. In fact, the kinetics of this step has been reported to be fast, or slow, and there is some agreement to think that this step is complicated by adsorption or electrocrystallisation phenomena. In this talk, we will tackle the questions of the chromium chlorides solubility, of the Cr(III) or Cr(II) adsorption on various substrates and the kinetics of the final electron exchange. 

In 2005, it was shown that the reduction of the aryl chromium(II) chloride species, Ar CrCl, with KCg afforded the Cr(I)-Cr(I) dimer Ar CrCrAr [19], in which the chromium atoms are linked by a fivefold metal-metal interaction. The effects of different terphenyl ligands on the quintuple Cr-Cr bonding in ArCrCrAr (Ar = 4-X-Ar, X = H, F, MeO or SiMeg) dimers were also studied (see Sect. 7.2), and these dimers were similarly prepared by reduction of the corresponding aryl chromium chlorides [20]. 

One of the methods of preparing metal quinoxalinoporphinazines involves the thermolysis of quinoxaline 65a with dry manganese and chromium chlorides at 220 °C, which leads to 129 (R = R = R = R = H, X = Mn, CrCl) in 80-84% yields (1997RUP2074188,1996RUP2052464). Similarly, heating quinoxaline 65j with the acetates of zinc, cobalt, or copper at 220° C without any solvent, but in the presence of ammonium molybdate as a catalyst resulted in corresponding metal complexes of the macrocycles 129 (R = R = R = H, R = f-Bu, X = Zn, Co, Cu) in 57-74% yields (2008ZOB1214). 

The anhydrous halides, chromium (ITT) fluoride [7788-97-8], CrF, chromium (ITT) chloride [10025-73-7], CrCl, chromium (ITT) bromide [10031-25-1], CrBr, and chromium (ITT) iodide [13569-75-0], Crl, can be made by the reaction of Cr metal and the corresponding halogen at elevated temperatures (12,36). Other methods of synthesis for the haUdes are also possible (36—38). All of the haUdes have a layer stmcture and contain Cr(III) in an octahedral geometry. They are only slightly soluble in water but dissolve slowly when Cr(II) or a reducing agent such as Zn or Mg is added. 

The dehydration of fructose 40 or glucose into 5-hydroxymethylfurfural 41 is a process which has been exploited to convert biomass into higher value products. The reaction has been achieved using a chromium NHC complex, formed in situ from CrCl and the NHC 42 (Scheme 11.10) [16], The reaction is performed in the ionic liquid BMIM+Cl (l-butyl-3-methylimidazolium chloride). 

The anhydrous chromium (III) chloride may be obtained by heating the hydrated salt CrCls 6H2O with SOCI2 and subliming the product in a stream of chlorine at 600°C. Alternatively, the red-violet anhydrous chloride can be obtained by passing chlorine gas over a mixture of chromic oxide and carbon ... 

Chromium(III) chloride has very low solubility in pure water. However, it readily dissolves in the presence of Cr2+ ion. Reducing agents such as SnCla can solubilize CrCls in water. It forms adducts with many donor ligands. For example, with tetrahydrofuran (THF) in the presence of zinc, it forms the violet crystals of the complex CrCF 3THF. 

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