Cobalt dichloro

Cobalt, dichloro(l, 10-diamino-4,7-dithiadecane)-configuration, 1,199 Cobalt, dichloro(triethylenetetramine)-chirality, 1,194 isomerization, 1, 467 isomers, 1,201... 

Many of these cobalt complexes will catalyze the reduction of organic compounds by borohydride, hydrazine, thiols, etc. Cobalt cyanide complexes will catalyze the reduction of a,j8-unsaturated acids by borohydride (105) DMG complexes the reduction of butadiene and isoprene by borohydride, but not by H2 (124) Co(II) salen, the reduction of CHCI3 and CH3CCI3 to the dichloro compounds by borohydride (116) and cyanocobalamin, the selective reduction of -CCI2- by borohydride to -CHCl- in compounds such as aldrin, isodrin, dieldrin, and endrin without... 

Molecules having only a sulfoxide function and no other acidic or basic site have been resolved through the intermediacy of metal complex formation. In 1934 Backer and Keuning resolved the cobalt complex of sulfoxide 5 using d-camphorsulfonic acid. More recently Cope and Caress applied the same technique to the resolution of ethyl p-tolyl sulfoxide (6). Sulfoxide 6 and optically active 1-phenylethylamine were used to form diastereomeric complexes i.e., (-1-)- and ( —)-trans-dichloro(ethyl p-tolyl sulfoxide) (1-phenylethylamine) platinum(II). Both enantiomers of 6 were obtained in optically pure form. Diastereomeric platinum complexes formed from racemic methyl phenyl (and three para-substituted phenyl) sulfoxides and d-N, N-dimethyl phenylglycine have been separated chromatographically on an analytical column L A nonaromatic example, cyclohexyl methyl sulfoxide, did not resolve. 

In contrast with the Schiff base salen, salicylaldehyde oxime (79) (salox) complexes of Co have received comparatively little attention, but a series of bis-bidentate divalent complexes of the form iraiis-Co(sa 1 ox)2( D M SO)2 have been reported.343 The heterocyclic bidentate oxime violurate (lH,3H-pyrimidine-2,4,5,6-tetrone 5-oximate, Hvi) (80) and its /V-methyl (mvi) and /V,/V -dimethyl (dmvi) derivatives form high-spin divalent [Co(vi)]+ and Co(vi)2 complexes, whereas [Co(vi)3] is low spin.344 The mixed-ligand Co(dmvi)2(phen) complex is also low spin. The crystal structure of m-Co(pxo)2Br2 (pxo = 2-acetylpyridine-l-oxide oxime) is isostructural with the Ni11 relative.345 The dichloro complex also adopts a cis configuration. The tridentate dioximes 2,6-diformyl-4-methylphenol dioxime and 2,6-diacetyl-4-methylphenol dioxime (Hdampo) form binuclear complexes of the type (81a) and (81b) respectively.346 Cobalt oxide nanoparticles were prepared by... 

The electrochemistry of cobalt-salen complexes in the presence of alkyl halides has been studied thoroughly.252,263-266 The reaction mechanism is similar to that for the nickel complexes, with the intermediate formation of an alkylcobalt(III) complex. Co -salen reacts with 1,8-diiodo-octane to afford an alkyl-bridged bis[Co" (salen)] complex.267 Electrosynthetic applications of the cobalt-salen catalyst are homo- and heterocoupling reactions with mixtures of alkylchlorides and bromides,268 conversion of benzal chloride to stilbene with the intermediate formation of l,2-dichloro-l,2-diphenylethane,269 reductive coupling of bromoalkanes with an activated alkenes,270 or carboxylation of benzylic and allylic chlorides by C02.271,272 Efficient electroreduc-tive dimerization of benzyl bromide to bibenzyl is catalyzed by the dicobalt complex (15).273 The proposed mechanism involves an intermediate bis[alkylcobalt(III)] complex. 

Allylic acetoxylation of cyclohexene (96) at 80 °C affords 3-acetoxycyclohexene (97) in 67% yield (Scheme 36). It was found that the catalytic double-bond isomerization of 3-phenylpropene proceeds by the action of an electrochemically generated 17-electron Co(II) species [132]. The cobalt(III)-mediated electrooxidative decomposition of chlorinated organics, that is, l,3-dichloro-2-propanol, 2-monochloro-propanol, and so on, has been performed... 

This is another of the very interesting contributions in Tobe s paper. Tobe has studied substitution reactions of the dichloro-bis(ethylenediamine)cobalt(III) ion in methanol, reported the preparation of the supposed solvo intermediate that would be required, and studied the rate of the chloride anion entry into this supposed solvo intermediate. He reports that the lability of methanol in this complex is insufficient to allow the complex to be an intermediate in a substitution process of the dichloro complex. Yet it is possible to obtain, in the case of the dichloro-chloride exchange, a term in the rate law for the free ion. This leads to the conclusion that, in fact, one has a genuinely unimolecular substitution process. 

Cobalt (III) Dichloro-bis-ethylenediamino Chlorate, [Co(en)2Cl2]C103 Cobalt (III)-... 

Dichloro-bis-ethylenediamino Perchlorate, [Co(en)2Cl2]C104 Cobalt (III) Tris-ethylene-diamtno Trinitrate, [Co(en)3](N03)3... 

O6C6CI4OS2, Osmium, hexacarbonyl(di-/i-chloro)(dichloro)di-, 34 219 O6C0KN3C20H29, Cobalt(III), tricyano(cyclo-pentadienyl)-, (18-crown-6)potassium, 34 169... 

Iron-catalyzed alkenylation of Grignard reagents was used by Cahiez and Avedissian to prepare the pheromone of Argyroplace Leucotetra in three steps from l,2-( )-dichloro-ethene (Scheme 63). Two successive alkenylation reactions, the first involving a cobalt catalysis, the second an iron catalysis, allow one to obtain the desired product in 45% overall yield. 

Just as ammonia groups maybe replaced by acid, so ammonia groups may be replaced by water molecules. These aquo salts, as they arc called, were represented by Jorgensen 1 as oxonium salts. For instance, dichloro-tetrammino-cobaltic chloride is transformed into aquo-dichloro-triammino-cohaltic chloride by replacement of one ammonia, molecule by one water molecule, a reaction which was represented thus ... 

Hydrate Isomerism.—As its name implies, this depends on the position of water in the molecule, just as in the case of the acido compounds. If two or more molecules of water are present in a molecule of ammine, the water may be present within the co-ordination complex or outside of it. For instance, the compound Cr en2.(H20)2.Br3 exists in isomeric forms. It may have all the water within the complex, in which case the formula will be [Cr en2(H20)2]Br3. In solution the whole of the bromine is precipitated by silver nitrate. On the other hand, the compound may have one molecule of water in the complex and the other outside, in which case the formula is [Cr en2(IT20)Br]Br2.H20, and only two-thirds of the bromine are precipitated by silver nitrate. Another example of this kind occurs in the cobalt series chloro-aquo-tetrammino-cobaltic chloride, [Co(NTI3)4Cl.H20]Cl2, is violet in colour, and is isomeric with dichloro-tetrammino-cobaltie chloride monohydrate, [Co(N1I3)4CI2]C1.H20, which is green. 

The isomers of type [M(NIT3)4R2]R differ in properties, solubility, colour, and reactivity. For instance, the dichloro-tctrammino-cobaltic chlorides are green and violet respectively. The violet-coloured salt is known as the violo salt and the green as the prasco salt. 

The following table shows the rotation of the chromic salts described and of the corresponding optically active dichloro-cobalt salts,2 showing that the optical activity depends on the central atom as well as the surrounding groups in the complex.3... 

Ionisation Metamerism.—Numerous examples of this type of isomerism occur in the cobalt-ammine series, such as the two metameric substances, ehloro-nitrito-tetrammino-cobaltic chloride, [Co(NH3)4Cl. NOJC1, and dichloro-tetrammino-cobaltic nitrite, [Co(NH3)4C12]N02.1... 

Diaquo - dipyridino - diammino - cobaltie cliloridc, [Co py2 XII3)2 (H20)2]C13, is one of the most stable of the aquo-salts, and requires to be heated for a considerable time before it passes into dichloro-dipyridino-diammino-cobaltic chloride, [Co py2(NII3)2Cl2]Cl. The aquo-pentammino-cobaltic salts, on treatment with ammonia, may be changed into hydroxo-pentammino-cobaltic salts thus ... 

The aquo-salts generally readily pass into the acido-ammino salts for example, aquo-pentammino-eobaltic chloride and diaquo-tetram-mino-cobaltic chloride are transformed into ehloro-pentammino-cobaltic chloride and dichloro-tetrammino-cobaltie chloride respectively on leaving concentrated aqueous solutions to stand for some time. 

The bromide, [Co en2H20.0H]Br2.H20, is obtained from the chloride or from iraws-dichloro-diethylenediamino-cobaltic chloride by treating it with concentrated aqueous potassium hydroxide and, after cooling to 0° C., neutralising the solution obtained with concentrated hydrobromie acid. It is a red crystalline powder, and resembles the chloride in properties. 

Chloro-triaquo-diammino-cobaltic Sulphate, [Co(NH3)2(H30)3 Ci]S04.H.,0, is obtained by decomposing an aqueous solution of acid dichloro-diaquo-diammino-cobaltic sulphate, [Co(b IIg)2(H20)2Cl2]S04H, with a small quantity of sulphuric acid and evaporating the solution in vacuo. It separates in indigo-coloured crystals and is soluble in water, giving a blue solution. 

The violeo- or 1-, 2-dibromo-tetrammino-cobaltic salts may be prepared by methods similar to those used for the corresponding 1-, 2-dichloro-salts. 

Dinitro-tetrammino-cobaltic Chloride, [Co(NH3)4(N03)2] Cl, is obtained from the sulphate by treating it with barium chloride, or by heating a solution of dichloro-tetrammino-cobaltic ehloride in dilute acetic acid with sodium nitrite.3 It is soluble in water, and separates from solution in reddish-yellow rhombic crystals. The aqueous solution, however, decomposes on standing. If a cold aqueous solution be treated with dilute nitric acid the nitrate separates concentrated hydrochloric acid decomposes the salt with formation of the chloro-nitro-chloride, [Co(NH3 )4 (NO 2)C1] Cl.3... 

Oxalato-tetrammino-cobaltic Chloride, [Co(NH3)4(C204)]C1, is prepared by dissolving chloro-aquo-tetrammino-eobaltic chloride in an aqueous solution of oxalic acid and heating the mixture for some time. The oxalato-compound gradually crystallises from the warm solution, and the crystals are collected and washed on the filter with alcohol until the filtrate is free from chlorine and from oxalic acid. It crystallises in carmine-red six-sided plates if dissolved in concentrated sulphuric acid and concentrated hydrochloric acid is added to the liquid, it is transformed into dichloro-tetrammino-cobaltic chloride. Sodium nitrite and acetic acid convert it into dinitro-tetrammino-cobaltic chloride.1... 

Dichloro-diethylenediamino-cobaltic Nitrate, [Co en2Cl2] N03, is precipitated almost completely from a solution of the chloride by nitric acid. The precipitate is collected, washed with acid and then with alcohol. It is sparingly soluble in water, and if heated with water for some time gives a violet solution. 

The corresponding dichloro-tetrapyridino-cobaltic salts, [Co py4Cl2]R, have also been prepared. These are analogous to the frans-tetrammino-series. All axe green crystalline salts. ... 

These salts resemble closely the salts just described. The chloride of the series exists, like dichloro-aquo-triammino-cobaltic chloride, in two stereo-isomeric forms. 

Dichloro - diaquo - diammino - cobaltic Chloride, [Co(NH3)2 (H20)oC12]C1, is prepared from potassium tetranitro-diammine cobalt, [Co (XH.,) 2(XO 2) JK, by mixing it with concentrated sulphuric acid, cooling, and decomposing the sulphate with concentrated hydrochloric aeid. It crystallises in light green dichroie needles. 

These salts are obtained from the dichloro-aquo-triammino-cobaltic salts.3... 

The salts of this series decompose on treatment with hydrochloric acid, giving dichloro - aquo - triammino - cobaltic chloride, cobaltous chloride, and chlorine. 

It is transformed into e/s -diaquo-cliethylenediainino-cobaltic chloride on treatment with concentrated hydrochloric add dilute hydrochloric acid reacts with the compound, with formation of ci.s-dichloro-diethylenedianiino-eobaltic chloride and potassium hydroxide transforms the salt into cA-hydroxo-aquo-diethylenediamino-cobaltic nitrate. 

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