Green anions

Ultrafast ESPT from the neutral form readily explains why excitation into the A and B bands of AvGFP leads to a similar green anionic fluorescence emission [84], Simplistic thermodynamic analysis, by way of the Forster cycle, indicates that the excited state protonation pK.J of the chromophore is lowered by about 9 units as compared to its ground state. However, because the green anionic emission is slightly different when it arises from excitation into band A or band B (Fig. 5) and because these differences are even more pronounced at low temperatures [81, 118], fluorescence after excitation of the neutral A state must occur from an intermediate anionic form I not exactly equivalent to B. State I is usually viewed as an excited anionic chromophore surrounded by an unrelaxed, neutral-like protein conformation. The kinetic and thermodynamic system formed by the respective ground and excited states of A, B, and I is sometimes called the three state model (Fig. 7). 

MnOj- Green anion—stable in aqueous solutions with [OH ] > 1M crystalline salts. 

Ten or so years later, in the 1930s, Edward Zintl conducted a series of more systematic studies of these systems. He carried out potentiometric titrations of liquid ammonia solutions of alkali metals with various p metal salts, typically halides. Thus, the titration of a sodium solution with lead(II) iodide revealed that the green anionic species in solution are Pbg. Zintl and coworkers also discovered that... 

MnOj- Green anion — stable in aqueous solutions with [OH" ] > IM crystalline salts. 

Hydroxide. Aqueous OH slowly precipitates Rh as the yellow hydroxide, Rh203-H20, soluble in excess OH. From a hot solution the product is darker, and the separation is faster from a sulfate solution than from a chloride one. The precipitate dissolves in excess NH3. The oxide, Rh203, is slightly soluble in concentrated OH". The dioxide, Rh02, is insoluble in OH", but Rh02-aq dissolves as a green anion. 

Compton R G, Spaokman R A, Wellington R G, Green M L H and Turner J 1992 A Cgg modified eleotrode. Eleotroehemioal formation of tetra-butylammonium salts of Cgg anions J. Electroanal. Chem. Interfacial... 

Some straightforward, efficient cyclopentanellation procedures were developed recently. Addition of a malonic ester anion to a cyclopropane-1,1-dicarboxylic ester followed by a Dieckmann condensation (S. Danishefsky, 1974) or addition of iJ-ketoester anions to a (l-phenylthiocyclopropyl)phosphonium cation followed by intramolecular Wittig reaction (J.P, Marino. 1975) produced cyclopentanones. Another procedure starts with a (2 + 21-cycloaddition of dichloroketene to alkenes followed by regioselective ring expansion with diazomethane. The resulting 2,2-dichlorocyclopentanones can be converted to a large variety of cyclopentane derivatives (A.E. Greene. 1979 J.-P. Deprds, 1980). 

These green radical ions react with styrene to produce the red styrem radical anions ... 

Plutonium(III) in aqueous solution, Pu " ( 4)> is pale blue. Aqueous plutonium(IV) is tan or brown the nitrate complex is green. Pu(V) is pale red-violet or pink in aqueous solution and is beUeved to be the ion PuO Pu(VI) is tan or orange in acid solution, and exists as the ion PuO. In neutral or basic solution Pu(VI) is yellow cationic and anionic hydrolysis complexes form. Pu(VII) has been described as blue-black. Its stmcture is unknown but may be the same as the six-coordinate NpO (OH) (91). Aqueous solutions of each oxidation state can be prepared by chemical oxidants or reductants... 

In the present work the acid-base surface properties of three Al O samples for a chromatography are investigated acidic (I), basic (II) and neutral (III) ones with the using of heterogeneous titration of their suspensions by HCl and NaOH solutions. To establish the correlations between the acid-base and adsoi ption properties studied Al O the representatives of cationic dyes -diamond green (DG), fuchsine (F) and anionic dyes - eriochrom black T and chromic dark blue have been used. 

In this work hybrid method is suggested to determine anionic surfactants in waters. It is based on preconcentration of anionic surfactants as their ion associates with cationic dyes on the membrane filter and measurement of colour intensity by solid-phase spectrophotometry method. Effect of different basic dyes, nature and hydrophobicity of anionic surfactants, size of membrane filter pores, filtration rate on sensitivity of their determination was studied. Various cationic dyes, such as Methylene Blue, Crystal Violet, Malachite Green, Rhodamine 6G, Safranin T, Acridine Yellow were used as counter ions. The difference in reflection between the blank and the sample was significant when Crystal Violet or Rhodamine 6G or Acridine Yellow were used. 

Ms " clusters have 12 framework bonding electrons as has [BsHs]- (p. 161) the anions are also isoelectronic with the well-known cation [Bis]. Similarly, the alloy NaSn. 2.23 reacts with cryptand in ethylenediamine to give dark-red crystals of [Na(ciypt)]4 [Sng] the anion is the first example of a C41, unicapped Archi-median antiprism (Fig. 10. lOc) and differs from the >3/, structure of the isoelectronic cation [Bis] + which, in the salt Bi+[Bi9] +[HfCl6]5 (p. 591), features a tricapped trigonal prism, as in [BgHg] " (p. 153). The emerald green species [Pb9] , which is stable in liquid NH3 solution, has not so far proved amenable to isolation via ciyptand-complexed cations. 

Of the anhydrous dihalides of iron the iodide is easily prepared from the elements but the others are best obtained by passing HX over heated iron. The white (or pale-green) difluoride has the rutile structure the pale-yellow dichloride the CdCl2 structure (based on cep anions, p. 1212) and the yellow-green dibromide and grey diiodide the Cdl2 structure (based on hep anions, p. 1212), in all of which the metal occupies octahedral sites. All these iron dihalides dissolve in water and form crystalline hydrates which may alternatively be obtained by dissolving metallic iron in the aqueous acid. 

Complexes o/M". The absence of any other oxidation state of comparable stability for nickel implies that compounds of Ni" are largely immune to normal redox reactions. Ni" forms salts with virtually every anion and has an extensive aqueous chemistry based on the green [Ni(H20)6] + ion which is always present in the absence of strongly complexing ligands. 

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