III Nitrate

Many methods have been used for the preparation of various acidopentammineeobalt(III) salts.1 In some instances these procedures are specific for the synthesis of a particular salt. The procedure suggested here involves the reaction of carbonatopentamminecobalt(III) nitrate with an acid or acid salt. The resulting reaction mixture may then be digested for a short time to yield the desired product, or the aquo complex is isolated and converted to the acido compound at an elevated temperature. This method appears to be completely general and has been used to synthesize complexes containing coordinated bromide, chloride, thiocyanate, sulfate, formate, and various substituted acetates, benzoates, and benzenesulfonates in addition to those described here. 

A solution of 300 g. of cobalt (II) nitrate 6-hydrate (1.03 mols) in 150 ml. of water is thoroughly mixed with a solution of 450 g. of ammonium carbonate (4.68 mols) in 450 ml. of water and 750 ml. of concentrated aqueous ammonia (sp. gr. 0.90, 28% NH3). A stream of air is bubbled slowly through the mixture for 24 hours. After the mixture has been cooled in an ice-salt bath overnight, the product is collected on a filter, washed with not more than 50 ml. of ice- 

Ten grams of carbonatopentamminecobalt(III) nitrate (0.036 mol) is suspended in 25 ml. of water, and 4.5 g. of ammonium hydrogen fluoride (0.079 mol) and 15 g. of ammonium fluoride (0.405 mol) are added. The reaction mixture is kept at approximately 90° in a water bath for 1 hour, with occasional stirring. During this digestion some decomposition takes place, and noticeable quantities of ammonia are evolved. The mixture is then cooled to room temperature, 75 ml. of water being added to keep the products in solution. This solution is filtered, and 20 g. of solid ammonium nitrate (0.25 mol) is added to the filtrate. Pink crystals separate immediately after the mixture is cooled in an ice-salt bath. The product is collected on a filter, washed with 10 ml. of ice-cold water, followed by alcohol and ether, and then dried at 90°. Yield, 6 g. (58%). 

The mixture is stirred at a rapid rate and heated for 30 minutes to 126°, whereupon the black slurry thickens. Only approximately 1 ml. of the sodium hydroxide is consumed in this initial heating. The reaction is then allowed to proceed rapidly at 128 to 139° for 2 hours. In the course of the reaction the mixture becomes light tan and appreciably less viscous, and the theoretical amount of sodium hydroxide is required to neutralize the hydrogen chloride which is evolved. Very little additional hydrogen chloride is liberated during another hour of heating. 

The solid is filtered, washed repeatedly with chloroform or benzene, and dried in vacuo the yield is 99%. Anal. Calcd. for FeCl2 Fe, 44.06. Found Fe, 43.89. 

Checked by John W. Simmons, f Gerhardt Jabs, and Mark M. Chamberlain f 

The first salts of this series were prepared by Vortmann1 and later extensively investigated by Jorgensen,2 who, however, gave only semiquantitative synthetic preparations. 

The salt crystallizes in violet-red to carmine-red prisms, depending on the crystal size. The solubility at room temperature is one part of the salt in fifteen parts of water. The aqueous solution has a basic reaction to litmus. Dilute acids form the diaquotetrammine salt, whereas concentrated acids form the diacido- or monoacidoaquotetram-mine complex. Treatment of the salt with dilute acid, then with an excess of hot dilute ammonia, forms the aquopen-tamminecobalt(III) series of salts. The salt is stable indefinitely, samples 40 years old having yielded satisfactory synthetic results. 

Since the x vw-CK-isomer is favored thermodynamically, it can be isolated in high yields by direct oxidation of Co(II) in the presence of the ligands and decolorizing carbon as a catalyst.  

The dark red-violet crystals of syw-c/x-[Co(edda)(en)] NO3 dissolve in water at room temperature to give a solution stable to isomerization. The visible absorption spectrum in water shows 9 (87.3), 448 (shoulder), 

362 nm (113). The proton NMR spectrum of the complex has been assigned. The isomer is characterized by its acetate methylene proton resonances, which occur at 4.37, 4.07, 3.49, and 3.20 ppm from the internal reference sodium 3-(trimethy Isilyl)-1 -propanesulfonate. 

RESOLUTION OF sym-cis- [ (ETHYLENEDIAMINE)[ ETHYLENEDI-AMINE-A,A -DIACETATO(2- )] COBALT(III)] NITRATE 

Disilver tartrate is prepared in the following manner. (During the synthesis the reaction mixture is shielded from light.) A solution of 3.8 g (0.025 mole) of (+)-tartaric acid in 15 mL of water, to which has been added 2 g (0.050 mole) of 98% sodium hydroxide in 10 mL of water, is added dropwise to a stirred solution of 8.5 g (0.050 mole) of silver nitrate in 25 mL of water. After about 30 minutes of stirring, the precipitate is allowed to settle, filtered, and washed with five 30-mL portions of water and then acetone. The air-dried disilver tartrate (7.6 g) is stored in a brown bottle. 

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Anhydrous liquid ammonia (note 2) (900 ml) was drawn from a cylinder and introduced into the flask. Iron(III) nitrate (lOO mg) was added and, as soon as a uniformly brown solution had formed (after stirring for a few seconds), about 0.7 g of lithium (from the starting amount of 7 g) was cut into two or three pieces and immediately introduced into the flask. After 10-15 min the blue colour had disappeared completely and a white suspension of lithium amide had formed. The remainder of the 7 g (1 mol) of lithium was then cut up and introduced. In most cases the conversion was finished v/ithin about 30 min (note 3). 

In contrast to the reaction with lithium amide, the sodium amide suspension immediately settles out after stopping the stirring and the supernatant ammonia has a grey or black colour, due to colloidal iron. In some cases it took a long time before all of the sodium had been converted (note 4). A further 0.1 g of iron(III) nitrate was then added to accelerate the reaction and some liquid ammonia was introduced to compensate for the losses due to evaporation. 

Thallium(III) acetate reacts with alkenes to give 1,2-diol derivatives (see p. 128) while thallium(III) nitrate leads mostly to rearranged carbonyl compounds via organothallium compounds (E.C. Taylor, 1970, 1976 R.J. Ouelette, 1973 W. Rotermund, 1975 R. Criegee, 1979). Very useful reactions in complex syntheses have been those with olefins and ketones (see p. 136) containing conjugated aromatic substituents, e.g. porphyrins (G. W. Kenner, 1973 K.M. Smith, 1975). 

III) nitrate 4-water (III) oxide (III) sulfate 8-water Yttrium chloride fluoride... 

Nitrate. Cerium(III) nitrate hexahydrate [10294-41 -4] Ce(N03) 6H20, is a commercially available soluble salt of cerium, and because of ready decomposition to the oxide, it is used, for example, when a porous sohd is to be impregnated with cerium oxide. The nitrate is very soluble in water, up to about 65 wt %. It is also soluble in a wide range of polar organic solvents such as ketones, alcohols, and ethers. 

Gallium (III) nitrate (9H2O) [63462-65-7] M 417.9, m ca 65°, Recrystd from H2O (sol 295g/100mL at 20°). White deliquescent colourless powder soluble in H2O. absolute EtOH and Et20. Loses... 

It is these reactions that impart the characteristic yellow to reddish-brown coloration of the hydroxoaquo species to aqueous solutions of iron(III) salts, whereas the undissociated ion [Fe(H20)6] is pale mauve, as seen in crystals of iron(III) alum [Fe(H20)6][K(H20)6](S04)2 and iron(III) nitrate [Fe(H20)6](N03)3.3H20. Such reactions may proceed to the stage where the diminished charge on the hydrated cation permits the formation of oxobridged. 

Aqueous solutions of dimetiiylgold(III) nitrate easily react with pyrazole and 3,5-dimethylpyrazole to form the pyrazolate complexes 271 (R = H, Me) [85 JOM (295)401]. However, 3,5-diphenylpyrazole gives the complex [Me2Au(3,5-Ph2pzH)2], where the ligand is not deprotonated. To obtain the 3,5-diphenylpyra-zolate complex, dimethylgold(III) iodide must be reacted with silver diphenylpyra-zolate. 

Eisenozyd, n. iron oxide, specif, ferric oxide, iron(Ul) oxide. — salpetersaures —, ferric nitrate, iron(III) nitrate (and so for other salts). 

Iron(III) nitrate is soluble, but silver chloride is not When these two solutions are mixed, silver chloride precipitates. 

Summary Problem—cont d An electrolytic cell contains an aqueous solution of chromium(III) nitrate at 25°G Assume that chromium... 

Discussion. Potassium may be precipitated with excess of sodium tetraphenyl-borate solution as potassium tetraphenylborate. The excess of reagent is determined by titration with mercury(II) nitrate solution. The indicator consists of a mixture of iron(III) nitrate and dilute sodium thiocyanate solution. The end-point is revealed by the decolorisation of the iron(III)-thiocyanate complex due to the formation of the colourless mercury(II) thiocyanate. The reaction between mercury( II) nitrate and sodium tetraphenylborate under the experimental conditions used is not quite stoichiometric hence it is necessary to determine the volume in mL of Hg(N03)2 solution equivalent to 1 mL of a NaB(C6H5)4 solution. Halides must be absent. 

Standardisation. Pipette 10.0 mL of the sodium tetraphenylborate solution into a 250 mL beaker and add 90 mL water, 2.5 mL 0.1 M nitric acid, 1.0 mL iron(III) nitrate solution, and 10.0 mL sodium thiocyanate solution. Without delay stir the solution mechanically, then slowly add from a burette 10 drops of mercury(II) nitrate solution. Continue the titration by adding the mercury(II) nitrate solution at a rate of 1-2 drops per second until the colour of the indicator is temporarily discharged. Continue the titration more slowly, but maintain the rapid state of stirring. The end point is arbitrarily defined as the point when the indicator colour is discharged and fails to reappear for 1 minute. Perform at least three titrations, and calculate the mean volume of mercury(II) nitrate solution equivalent to 10.0 mL of the sodium tetraphenylborate solution. 

Pipette 25.0 mL of the potassium ion solution (about 10 mg K + ) into a 50 mL graduated flask, add 0.5 mL 1M nitric acid and mix. Introduce 20.0 mL of the sodium tetraphenylborate solution, dilute to the mark, mix, then pour the mixture into a 150mL flask provided with a ground stopper. Shake the stoppered flask for 5 minutes on a mechanical shaker to coagulate the precipitate, then filter most of the solution through a dry Whatman No. 40 filter paper into a dry beaker. Transfer 25.0 mL of the filtrate into a 250 mL conical flask and add 75 mL of water, 1.0 mL of iron(III) nitrate solution, and 1.0 mL of sodium thiocyanate solution. Titrate with the mercury(II) nitrate solution as described above. 

The solution should be free from the following, which either interfere or lead to an unsatisfactory deposit silver, mercury, bismuth, selenium, tellurium, arsenic, antimony, tin, molybdenum, gold and the platinum metals, thiocyanate, chloride, oxidising agents such as oxides of nitrogen, or excessive amounts of iron(III), nitrate or nitric acid. Chloride ion is avoided because Cu( I) is stabilised as a chloro-complex and remains in solution to be re-oxidised at the anode unless hydrazinium chloride is added as depolariser. 

The reaction mixture first turns muddy brown, due to the hydrolysis of thallium(III) nitrate to thallium(III) hydroxide and thallium(III) oxide, and then yellow with the separation of colorless thallium(I) nitrate. 

The mechanism of oxidation probably involves in most cases the initial formation of a glycol (15-35) or cyclic ester,and then further oxidation as in 19-7. In line with the electrophilic attack on the alkene, triple-bonds are more resistant to oxidation than double bonds. Terminal triple-bond compounds can be cleaved to carboxylic acids (RC=CHRCOOH) with thallium(III) nitrate or with [bis(trifluoroacetoxy)iodo]pentafluorobenzene, that is, C6F5l(OCOCF3)2, among other reagents. 

In a modified version of a previously published procedure <83JOC3214>, the thallium induced transposition of 3-acetyl-1-tosylpyrrole to the corresponding 2-(3-pyrrolyl)acetic acid has been reported employing thallium(III) nitrate supported on acidic montmorillonite K-10 <96SC1289>. In this sequence, Af-tosylpyrrole (39) undergoes regioselective C-3 acylation to afford 40 which is rearranged with T1(III)/K-10 in methanol to yield the ester 41. 

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