Complexes anionic acetato

The electron-releasing phosphine promotes oxidative addition of the bromo derivative to Pd(0) and, because of its bulkiness, readily generates free coordination sites by dissociation. Ethylene coordination and insertion then occur, followed by reductive elimination, triethylamine acting as a base to neutralize hydrogen bromide. As in most cases of transition metal-catalyzed reactions the fine details of the mechanism are still under investigation. Thus recent studies by Amatore s group suggest that the palladium(O) species formed by reduction of palladium acetate is an anionic acetato complex. 

Cinellu, M.A., Minghetti, G., Pirma, M.V., Stoccoro, S., Zucca, A. and Manassero, M. (2000) Gold(lll) derivatives with anionic oxygen ligands mononuclear hydroxo, alkoxo and acetato complexes. Crystal structure of [Au(bpy)(OMe)2][Pp6]. Journal of the Chemical Society, Dalton Transactions, (8), 1261. 

Catalytically active species derived from 4. Spectrophotometric titration of the backbone ligand of the sngar discriminating dinuclear copper(ll) complex N, N-bis[(2-pyridylmethyl)-l,3-diaminopropan-2-olato] (//-acetato) dicoppeftll) perchlorate (Cu2(bpdpo), 4) in the presence of two equivalents of copper(ll) ions with sodium hydroxide indicates successive replacement of the bridging acetate anion bound in the sohd state with two hydroxyl ions and two water molecnles in alkaline aqneons solntion (eqs. 2 and 3) (20-22). Two species, [Cu2(L h)(OH)] (4a) and [Cn2(L h)(OH)2] (4b), are thus observed in a pH-dependent equihbrium (20). 

Studies of the solubility of polonium(IV) in formic, acetic, oxalic and tartaric acids have provided evidence of complex formation,48 with the acetato complex emerging as more stable than the hexachloro anion. Other studies of the solubility of polonium(IV) hydroxide in carbonate49 and nitrate50 solution, together with investigations51 of the ion exchange behaviour of polonium(IV) at high nitrate ion concentration, have been discussed in terms of the formation of anionic complex species. 

The starting material bis(pinacolato)diboron is a poor Lewis acid and 1 B-NMR of KOAc and B2bin2 in DMSO-d6 shows no evidence of the coordination of the acetoxy anion to a boron atom leading to a tetrahedral activated species. However, the formation of an (acetato)palladium(II) complex after the oxidative addition of the halide influences the reaction rate of the transmetalation step. The Pd-O bond, which consists of a hard Lewis base with a soft Lewis acid, is more reactive than a Pd-X (X=Br, I) bond. In addition, the high oxophilicity of boron has to be considered as a driving force for the transmetalation step, which involves an acetato ligand. 

The uranyl nitrato and acetato anionic complexes are similar. From low acid 5M metal nitrate 14) or acetate solutions the relative ratios of U02(N03)4- to U02(N03)3 and U02(C2H302)4 to U02(C2H302)3 in the resin phase closely reflect the difference in formation constants of the tetra complexes from the tri complexes. This is despite the fact that the formation constants of the triacetate complex and the trinitrate complex from the respective lower complexes are obviously different and the aqueous phase contains mainly anionic species in the acetate case but essentially no anionic species in the nitrate case (14). 

U(acetato complex) DEAE(cellulose)anion-ex changer -i-K3[Fe(CN)6J (ring-oven) ng-Range 194)... 

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