Manganese acetate complex

Photoinitiation of polymerization of MMA and styrene by Mn(facac)3 was also investigated, and it was shown that the mechanism of photoinitiation is different [33] from that of Mn(acac)3 and is subject to the marked solvent effect, being less efficient in benzene than in ethyl acetate solutions. The mechanism shown in Schemes (15) and (16) illustrate the photodecomposition scheme of Mn(facac)3 in monomer-ethyl acetate and monomer-benzene solutions, respectively. (C = manganese chelate complex.)... 

Knowledge of stoichiometry of the induced reaction could help to distinguish whether chromium(V) or chromium(IV) species are involved in the oxidation of benzaldehyde. Thus, the Cr(V) hypothesis predicts that for each molecule of benzaldehyde oxidized two molecules of manganese dioxide should be formed, whereas the Cr(IV) predicts that one molecule of manganese dioxide should be formed for each two molecules of benzaldehyde oxidized. Unfortunately, the attempt to determine the stoichiometry of the induced reaction failed because the oxidized manganese species was not precipitated during the reaction presumably due to formation of acetate complexes in the concentrated acetic acid solution. 

An asymmetric C-H insertion using a chiral 3,3, 5,5 -tetrabromosubstituted (salen)manganese(m) complex 107 with TsN=IPh afforded insertion products with ee up to 89%.258 Che reported the first amidation of steroids such as cholesteryl acetate with (salen)ruthenium(n) complexes 108.259... 

A typical manganese-salen complex (27)[89] is capable of catalysing the asymmetric epoxidation of (Z)-alkenes (Scheme 18) using sodium hypochlorite (NaOCl) as the principle oxidant. Cyclic alkenes and a, (3-unsaturated esters are also excellent starting materials for example indene may be transformed into the corresponding epoxide (28) with good enantiomeric excess1901. The epoxidation of such alkenes can be improved by the addition of ammonium acetate to the catalyst system 911. 

Subsequent reaction of porphyrazines 170 and 171 with Cu(OAc)2 resulted in the selective metalation within the macrocyclic cavity to provide the corresponding copper complexes 166 (62%) and 172 (47%). Treatment of pz 170 with manganese acetate and iron sulfate in dimethyl sulfate gave the dmso adducts 173 (70%) and 174 (85%), respectively (168). Axial ligation was also observed when other metals were incorporated such as cobalt acetate, nickel acetate, and zinc acetate to give the metal complexes 175 (83%), 176 (70%), and 177 (90%) as the hydrates. The axial ligand of... 

We have not been able to unscramble the complex kinetics of p-xylene oxidation. Ravens studied the second stage of oxidation, that of p-toluic acid in acetic acid with cobalt and manganese acetates and sodium bromide (25), and established the rate equation... 

Nature of the Metallic Salt. The data in Figures 15, 16, and 17 also show the influence of another parameter—the nature of the metallic salt. The two kinds of salts were chosen because the chlorides are salts of a strong acid, and the acetate is that of a weak acid. The data obtained from both the duration of the reaction and the diamine quantity show that the kind of salt used is important to mechanochemical com-plexation. Use of manganese acetate gives scission of a larger number of complexing centers than does use of choride salts. 

Figure 16. Influence of milling duration on mechanochemical complexation for the system polyethylene terephthalate, ethylenediamine and manganese acetate...

Figure 19. Variation of amount of thermostable polymer from the complex of polyethylene terephthalate, ethylene-diamine, and Mn2+ (from manganese acetate) with milling...

The majority of complexes with six-member metal-cycles are represented by chelates of the type 422, obtained according to the scheme, analogous to (3.46), with participation of salicylidenanilines and their derivatives. Among the latter, we note the tetradentate ligands 612 (LH2), whose interaction (3.47) with manganese acetate leads to chelates MnL(OCOR) 282 [57] ... 

The same complexes were obtained by template synthesis with the use of derivatives either of benzalde-hyde, o-aminophenols, or manganese acetate, in hot methanol solution. 

Most of the coordination chemistry for the higher oxidation states of manganese involves the 3+ oxidation state a concise summary is provided by Cotton and Wilkinson (18). They include a discussion of the unusual structure for the manganese (III)-acetate complex ... 

The first [M Dm3(ttnFe)2](C104)2 complexes of this type were obtained [79] by the interaction of iron(II) acetate and copper, zinc, nickel, cobalt, and manganese acetates with dimethylglyoxime and 1,4,7-trimethyl-1,4,7-triazacyclononane ttn) in methanol in the presence of triethylamine (Reaction 20). In this case, a triazamacrocycle served as the protecting group in the octahedral capping nFe "03 fragment. 

Adam, W., Fell, R. T., Stegmann, V. R., Saha-Moeller, C. R. Synthesis of Opticaiiy Active a-Hydroxy Carbonyl Compounds by the Catalytic, Enantioselective Oxidation of Silyl Enol Ethers and Ketene Acetals with (Salen)manganese(lll) Complexes. J. Am. Chem. Soc. 1998,120, 708-714. 

The toluic aldehyde/HBF complex is then decomposed by heating between 130 and 180 C in the presence of a solvent (benzene). The BF3. HF and unconverted toluene are recovered and recycled. The o- and p-tohiic aldehydes are separated by crystallization. Purified p-toluic aldehyde is air-oxidized (in solution m acetic add) in the presence of manganese acetate, cobalt acetate and sodium bromide, by the technique employed for p-xylene. This takes place around 200°C, at 2.10 Pa absolute ... 

In summary, oxidative radical reactions by other metals are less common than single-electron transfer to cerium(IV), iron(III), copper(II), and especially manganese(III) complexes. However, even for manganese(III) acetate and cerium(IV) ammonium nitrate the synthetic potential is not completely utilized. During the next few years, many new applications should arise, which will focus on stereoselective reactions and the synthesis of complex organic molecules. 

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