A new and direct route to bis(acetylacetonato)dioxouranium(VI) dihydrate, U02(C5 H70 2}z·2H2 0, based upon the reaction of U03 ·4H 20 with acetylacetone (C5 H8 0 2 ), is described.

Fluoride amino acid complexes of vanadium(IV) of the type A[VOF2L(H2O)] (A = Naor NH4, L = cysteinate) and A[VOF3L(H2O)] (A = NH4 for L = alanine and A = Na, NH4 or K for L = serine) have been synthesised. The compounds have been characterised by chemical analyses, chemical determination of the oxidation state of vanadium, solution electrical conductance and magnetic susceptibility measurements, ESR, IR and electronic spectral studies. The vibrational spectra of the complexes indicate coordination of the amino acids through their carboxylate group to the metal centre. Also, the sulphydryl functionality provides an additional coordination site in cysteine-containing complexes. Fluoride appears to act as a stabilising ligand which helps in the solid-state isolation of the complexes.

An interpretative account of the results of reactions in aqueous medium of a highly peroxygenated vanadium(V) complex, K [V(O2 3]·3H2O, with different organic and inorganic substrates is presented. The reactions were monitored by solution EPR spectroscopy and isolation of products at different stages of the reactions. Redox reactions between diperoxide, K[VO(O2)2(H2O)] and VOSO4 were conducted. The results of the investigation suggest that secondary oxygen exchange-reaction occurs which not only depends on but also utilises the intermediates in the primary reaction during diperoxovanadate-dependent oxidation of VOSO4.

New mixed-fluoro complexes of UO22+ of the types A2[UO2(PO4)F(H2O)3]·3H2O [A = K (1), Na (2) or NH4+ (3)], A2[UO2(NO3)3F] · 3H2O [A = K (4), Na (5) or NH4+ (6) and [UO2(N2H4)2F2] · 2H2O (7) have been synthesized. The compounds have been characterized by analyses, electrical conductance measurements and electronic, IR and laser Raman (IR) spectroscopic studies. The occurrence of trans-linked (OUO), coordinated fluoride and bidentate co-ligands are the common features of complexes 1–7. Typically, the scanning electron micrographs of 2 and 7 provide evidence for their crystallinity and homogeneity. The laser Raman spectra of the aqueous solutions of the systems 1–6 and the solid complexes 1–7 were recorded separately. While for the reaction solutions (cf. 1–6) the symmetric stretching frequency of OUO was observed at ca 840 cm−1, the band was found to occur at ca 900 cm−1 for the solids 1–7. This has been interpreted in terms of the decrease in the hydration number of the coordination shell of UO22+ of the solid complexes.

Anhydrous alkali-metal tetrafluorodioxouranates(VI), A(2)[UO2F4] (A = Na, K or NH4). have been synthesised directly from the reaction of [UO2(O-2)].2H(2)O with aqueous HF and alkali-metal fluorides AF (A = Na, K or NH4). The yellow product obtained by addition of an alkali to an aqueous solution of [UO2(NO3)(2)].6H(2)O yielded, with aqueous HF and alkali-metal carbonates, the alkali-metal diaquatetrafluorodioxouranate(VI) monohydrates. A(2)[UO2F4(H2O)(2)].H2O (A = Na, K or NH4). The compounds are crystalline. Infrared and laser Raman spectroscopic investigations provided the basis of their structural assessment. The solution electrical conductance (ca. 242 Omega(-1) cm(2) mol(-1)) attests to their 2:1 ionic nature and stability in aqueous solution. Pyrolysis of [NH2](2)[UO2F4(H2O)(2)].H2O at 120 degrees C followed by deuteriation and IR spectroscopy of the product provided evidence for the occurrence of a molecule of lattice water and two aqua ligands.

Yellow-orange crystalline quinolinium fluorochromate (QFC) is easily prepared in a nearly quantitative yield by the interact ion of quinoline with CrO3 and hydrofluoric acid iii 1 : 1.5 : 1 molar ratio. The reagent is stable. Compared with pyridinium fluorochromate (PFC). the new reagent is more soluble in organic solvents and less acidic. QFC in CH2Cl2 readily oxidizes primary, secondary, and allylic alcohols to the corresponding carbonyls, benzoin to benzil, and anthracene and phenanthrene to anthraquinone and 9.10-phenanthrenequinone. respectively. Oxidations work well also in a variety of sensitive environments, e.g. isopropylidene functionality and trimethylsilyl ethers. Organic sulfides are transformed to sulfoxides at room temperature. The facile oxidation of triphenylphosphine to triphenylphosphine oxide by QFC iii CH2Cl2 or CH3CN provides a clear evidence for an oxygen-transfer reaction. The reduced product of QFC, isolated after such reactions. has been ascertained to be C9H7NH[CrO2F]. a chromium(IV) species. The advantages of QFC have been highlighted.

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The synthesis of mixed-ligand fluoro complexes of UO22+ of the types A3[UO2(GlyH)2F5] · 3H2O [A = K (1) or NH4+ (2)], K3[UO2(AlanH)2F5 · 2H2O (3), (NH4)5[UO2(CysH)2F5]·2H2O (4), [UO2(acac)F(H2O)2] · 3H2O (6), K2[UO2(acac)F3] (8) and [UO2(CH3COO)F(H2O)2] (9) (GlyH = glycine, AlanH = alanine, CysH− = cysteinate and acac− = acetylacetonate) is described. The complexes have been characterized by a combination of chemical analyses, solution conductance measurements and spectroscopic studies. Vibrational spectroscopy has been used for their structural assessment. Laser Raman spectrum could be recorded only for K2[UO2(acac)F3] (8), while an extensive fluorescence foiled such attempts on the other complexes. Each of the three amino acid co-ligands acts in a unidentate manner, being coordinated to UO22+ through the caroxylate oxygen atom. While glycine and alanine occur in the zwitter-ionic form, cysteine seems to be present as a uninegative ligand. The reaction of [UO2(acac)F(H2O)2]·3H2O (6) with aqueous HF produced [UO2F2] · 3H2O (7). Treatment of K3[UO2(GlyH)2F5] · 3H2O (1) with water afforded the hitherto unreported potassium heptafluorodioxouranate(VI) dihydrate, K5[UO2F7 · 2H2O (5), in a high yield with satisfactory ana measurement (590 Ω−1 cm2 mil−1). IR and laser Raman spectra provide clear evidence for the presence of trans-linked OUO and coordinated fluoride. The solution Raman spectrum of 5 is similar to that of its solid indicating that the structure in aqueous solution is the same as the solid. Scanning electron microscopy has been used to ascertain its homogeneity and crystalline nature.

Evidence for a manganese(III) intermediate, previously implicated in the [MnO4]--SO2 electron-transfer process, has been obtained by conducting the reaction in the presence of F-. A combination of in situ EPR and electronic absorption spectroscopies was used to follow the reaction course and physico-chemical techniques were used to ascertain the identity of the isolated manganese(III) products. The evidence suggests that in the presence of F- manganese(VII) is directly reduced to manganese(III) and thence to manganese(II).

A simple and rapid method for the simultaneous extraction of heavy metals using a new reagent 5-(2'-carbomethoxyphenyl)azo-8-quinolinol(R) into methyl isobutyl ketone (MIBK) and their subsequent determination by flame atomic absorption spectrometry is described. The method has been applied to the determination of Cu, Pb, Ni, Fe, Cr, Co and Mo in drinking and bore well waters. The extraction has been carried out with an aqueous to organic phase ratio to achieve around 30 fold preconcentration of metals. Extraction parameters and the influence of diverse ions have been studied. The detection limits (36) for Cu, Pb, Ni, Fe, Cr, Co and Mo are 0.07, 0.23, 0.15, 0.09, 0.22, 0.17, 0.38-mu-g/l, respectively. Higher preconcentration factors can be achieved by using a higher aqueous to organic phase ratio and lower concentration of metals can be determined.Determination of trace metals in natural and waste water is important for monitoring environmental pollution. Atomic absorption spectrometry has been particularly useful in the determination of trace metals because of its high specificity1,2. The limitations of detectibility by atomic absorption spectrometry often makes preconcentration of trace metals necessary. A number of techniques including co-precipitation and co-crystallisation3, use of organic co-precipitants4,5, chelate solvent extraction6-11, collection of complexes with poor solubility on micro-crystalline naphthalene12-13, chelating ion exchange resins14-17, and electrolysis18-20, have been used for the preconcentration of trace metals. Solvent extraction is of great value in preconcentration of trace metals as it is simple, rapid, easy to manipulate, eliminates matrix effects and provides matrix normalisation for the sample and standard. The preconcentration of trace metals achieved by extraction of their complexes in non-aqueous phase is well above the normal instrumental detection limit. In addition, the use of nonaqueous solvents further enhances the signal because of the change in liquid matrix such as viscosity, surface tension, burning rate, etc.Several chelating agents like ammonium pyrrolidinedithiocarbamate (APDC), cupferron, Oxine, diphenylcarbazone, acetylacetone, sodium diethyldithiocarbamate (NaDDC) are used for preconcentration but APDC and NaDDC are the reagents most generally used. APDC has been found to be more suitable than NaDDC specially at low pH values21,22. However, the use of APDC has certain disadvantages23,24. The rate of formation of metal complexes with APDC is generally slow to an extent that in some cases heating is desirable for complex formation such as in Cr-APDC. Some metal chelates of APDC are relatively unstable which require immediate determination and some undergo photodegradation. Kinrade et.al25 used DDDC (Diethylammonium diethyl dithiocarbamate) alongwith APDC to give stabilizing effect on metal-APDC complexes.In the present work, we have attempted to overcome these difficulties by choosing the reagent (R), an analogue of 5-(2'-carboxyphenyl)azo-8-quinolinol26 as a complexing reagent for extraction of seven elements (Cu, Pb, Ni, Fe, Cr, Mo, Co) in natural drinking water supplies and bore well water collected from different places.

A new and direct route tobis(acetylacetonato)dioxouranium(VI) dihydrate, UO2(C5H7O2)2·2H2O, based upon the reaction of UO3·4H2O with acetylacetone (C5H8O2), is described.

The importance of F− as a stabilizing ligand for V(III) and Mn(III) , both in aqueous solution as well as in solid compounds has been emphasized. A multitude of fluoro and mixed-fluoro complexes have been synthesized from aqueous solution and their structural motif expounded [1]. Routes to VF(C5H7O2)2, Na3VF6 and K3VF6 have been developed based on electron-transfer processes involving vanadium(V) and sacrificial reductants. The coligands for the fluoromanganates(III) have been drawn from SO42−, C2O42−, EDTA, HPO42−, glycine, 2,2′-bpy, 1,10-phen, and urea. An internal comparison of the empirical magnetic moments has enabled a magnetostructural correlationship. Pyrolysis of [MnF3(urea)2]. 3H2O at ca. 500°C affords a potential fluorinating agent, MnF3.