Acetonitrile manganese

C. HEXAKIS(ACETONITRILE)MANGANESE(II)BIS-TETRA-3,5-BIS(TRIFLUOROMETHYL)PHENYLBORATE ([Mn (NCMe)6] B[C6H3(CF3)2]4>2)... 

Hydroxyandrosta-4,6-dien-3-one. A suspension of 42 g of crude androsta-4,6-diene-3j ,17j -diol in 2000 ml of chloroform is treated with 250 g of activated, manganese dioxide. The mixture is then shaken vigorously for 15 min in a stoppered flask. The mixture is filtered and the manganese dioxide washed well with chloroform in order to elute material which initially remains adsorbed on the solid phase. The filtrate is concentrated to a pale yellow, crystalline residue. Recrystallization from acetonitrile gives 38 g (90%) of 17/ -hydroxyandrosta-4,6-dien-3-one as plates mp 211-214°. 

Solvents Water (purified water or water-for-injection grade) toluene, methanol, ethanol, ether, acetate, dimethyl sulfoxide, tetrahydrofuran, hexane, cyclohexane, dichloromethane, acetonitrile, acetone Oxidizing Agents Hydrogen peroxide, chromic acid, potassium permanganate, manganese dioxide, ozone... 

The host-guest interaction of manganese(II) with a range of ferrocene-containing species, which included the dithia derivative (219), has been investigated in acetonitrile. Complexation gave rise to a bathochromic shift of the lowest-energy ferrocene-centered d-d transitions. 

The related manganese(I) complexes of type /uc-[MnL(CO)3] (where L is one of the tetrathia macrocycles 1,4,7,10-tetrathiacyclododecane, 1,4,8-11-tetrathiacyclotetradecane, or 1,4,7,10,13-pentathiacyclopentadecane) were obtained by reaction of /hc-[Mn(CO)3(CH3COO)3] with L in acetonitrile. These species are readily decarbonylated with Me3NO to yield the corresponding ci5-[Mn(CO)2(L)]+ species. The facial arrangements in the products containing the 12- and 15-membered ring macrocycles were confirmed by X-ray structure determinations. 

Fig. 8.13. (a) Cyclic voltammograms for NOg in acetonitrile at scan rates of 0.1 and 7 V/s. (b) Experimental CVs for the oxidation of 1.7 x 10-3 M MnMe in the presence of various molar ratios of phosphine ligand and manganese complex. (Reprinted from D. Gosser, Cyclic Voltammetry, pp. 74, 77, 84, copyright 1993, VCH-Wiley. Reprinted by permission of John Wiley Sons, inc.)... 

Many transition-metal complexes have been widely studied in their application as catalysts in alkene epoxidation. Nickel is unique in the respect that its simple soluble salts such as Ni(N03)2 6H20 are completely ineffective in the catalytic epoxidation of alkenes, whereas soluble manganese, iron, cobalt, or copper salts in acetonitrile catalyze the epoxidation of stilbene or substituted alkenes with iodosylbenzene as oxidant. However, the Ni(II) complexes of tetraaza macrocycles as well as other chelating ligands dramatically enhance the reactivity of epoxidation of olefins (90, 91). 

C1F6N3PRuC,4H2i, Ruthenium(II), tris-(acetonitrile)chloro(V-l, 5-cyclooctadiene)-hexafluroophosphat(l -), 26 71 ClHgMn20KPC2l H1(i, Manganese, x-(chloromercurio)-p.-(diphenylphos-phino)-bis(tetracarbonyl)-(Mn—Mn), 26 230 ClIrP3C,4H4 , Iridium(I), chlorotris-(triphenylphosphine)-, 26 201... 

Dramatic shape selectivities in competitive olefin epoxidation was observed with picnic basket metalloporphyrins312 313 designed to exclude bulky axial ligands on one sterically protected porphyrin face. When oxidized with PhIO in acetonitrile in the presence of the rigid p-xylyl-strapped porphyrin, cis-2-octene reacted selectively versus ds-cyclooctene or 2-methyl-2-pentene, giving >1000 reactivity ratios.313,314 Some immobilized manganese(III) porphyrins proved to be as efficient as their homogeneous equivalents in epoxidation with PhIO.151,315... 

The oxidation of benzopyrylium perchlorate to coumarin is brought about by manganese dioxide in chloroform or acetonitrile (68AC(R)25l). 

Some comments about the choice of the conditions The use of acetonitrile as solvent and the selected temperature have been already discussed. Iron (III) and copper (II) were selected for a couple of reasons. First of all, they are ubiquitous ions and typical autoxidation catalysts. Iron (III) is a hard acid and copper (II) a borderline acid according to the HSAB classification, so it is reasonable to expect they will react differently, with a different complexing power. Manganese (II) has also been proposed as a widespread catalyst of autoxidation (49). 

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