Absorption yielding soluble complexes

Reduction of ZrIV in ZrX4-Al2X6 (X = Cl, Br or I) melts, with either zirconium or aluminum metal, yields soluble blue species. These species were not isolated, but they have been formulated as Zr(X2AlX2)3 complexes on the basis of their electronic spectra. Absorption bands at 17 400 (X = C1), 16 000 (X = Br) and 14 000 cm-1 (X = I) may be assigned to the 2t -2es transition of Zr111 in an octahedral environment of halide ions. The solid zirconium(III) halides exhibit ligand-field bands at closely similar frequencies.32... 

Thc pale greenish sail K7 Tc(OMc)f,l is soluble in methanol or ethanol and decomposes rapidly in aqueous solution, if the pH is lower than 12. Substitution reactions of the compound with glycolate or 1.2,4-butanetriolatc yielded the complex salts K2[Tc(eg)3 - iCnHsOII and K2 Tc(butri)2] CH3OH. IR absorptions between 450 and 460 cm" were assigned to the Tc-O stretching vibrations [368]. 

Discussion. Beryllium forms an acetylacetone complex, which is soluble in chloroform, and yields an absorption maximum at 295 nm. The excess of acetylacetone in the chloroform solution may be removed by rapid washing with O.lM-sodium hydroxide solution. It is advisable to treat the solution containing up to 10 g of Be with up to 10 mL of 2 per cent EDTA solution the latter will mask up to 1 mg of Fe, Al, Cr, Zn, Cu, Pb, Ag, Ce, and U. 

Therefore, other factors that have not yet been studied and are not easily quantifiable, such as the absorption properties of the C.-T. adduct at the surface of the metal powder and the solubility of the formed species should be important in determining the oxidation properties of C.-T. adducts towards metal powders. Furthermore, some extrinsic factors inherent to the experimental conditions, such as reaction temperature, reagent concentration, and nature of the solvent have been reported to affect the overall yield or the course of the reaction, and led to separation of different products in some cases.55 59 In any case, it appears that the simultaneous presence of the donor molecule and the di-/inter-halogen lowers the oxidation potentials of the metals, allowing their oxidation, dissolution, and complexation. 

The absorption and emission maxima of trimethinecyanine 9a (551 nm and 565 nm), squaraine 9b (631 nm and 641 nm), and cyanine 9c (784 nm and 805 nm) hardly change after complexation with a-CD and [S-CD in water, but the fluorescence quantum yields increase noticeably [28]. CD complexes of these water-soluble dyes containing reactive carboxylic functionalities have potential use as fluorescent labels. 

The reaction of acetylenes with the iron carbonyls gives a wide variety of stable complexes, the composition of which depends on the alkyne, the carbonyl, the reaction temperature, and the solvent used in the preparation (Table III) 116, 117, 118, 120, 182, 187). Iron dodecacarbonyl yields as many as seven different kinds of complexes, depending on the acetylene studied. The complexes are generally yellow, red, or black, soluble in organic solvents, and are invariably diamagnetic they show infrared absorption... 

The resolved complex is composed of two fractions, a soluble part, which comprises about 15% of complex I proteins, and a water-insoluble part consisting of the rest of the protein and the bulk of complex I lipids. The soluble fraction is easily separated from the insoluble material by centrifugation. Upon fractionation with ammonium sulfate, it yields a soluble flavoprotein containing iron and labile sulfide and a dark brown protein, which contains large amounts of iron and labile sulfide but no flavin. The latter appears to be an iron-sulfur protein and exhibits an EPR signal which is characteristic of iron-sulfur center 2 of intact complex I (46). Its absorption spectrum is shown in Fig. 8. The insoluble fraction also contains equimolar amounts of iron and labile sulfide and little or no flavin. 

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