Aluminum complexes perchlorates

Reduction of l-methyl-2-alkyl-.d -pyrroline and l-methyl-2-alkyl-.d -piperideine perchlorates with complex hydrides prepared in situ by partial decomposition of lithium aluminum hydride with the optically active alcohols (—)-menthol and (—)-borneol affords partially optically active l-methyl-2-alkyl pyrrolidines (153, n = 1) and 1-methy 1-2-alkyl piperideines (153, n = 2), respectively (241,242). 

Coordination of the aluminum atom of the reducing complex was proposed to take place both to the oxygen atom of the hydroxy group and to the nitrogen atom of the amino group. The asymmetric reduction of enamine perchlorates and ketimines with menthol and bomeol chiral auxiliary reagents (50,51) presumably involves coordination of aluminum to the nitrogen atom of the substrate. 

Ethers are weakly basic and are converted to unstable oxonium salts by strong acids such as sulfuric acid, perchloric acid, and hydrobromic acid relatively stable complexes are formed between ethers and Lewis acids such as boron trifluoride, aluminum chloride, and Grignard reagents (qv) (9) ... 

Both acid and base catalysis have been used extensively to catalyze exchange in aromatic, and to a lesser extent, heterocyclic molecules. In acid exchange, the most widely used catalysts are sulfuric acid,122,129, 131 phosphoric acid,132 trifluoroacetic acid5133 perchloric acid,134 aluminum chloride,135 and the phosphoric acid-boron trifluoride complex.132 These reactions constitute the simplest electrophilic substitution. The mechanism for such substitution in benzenoid compounds is now comparatively well understood 122 however, the problem of heteroaromatic electrophilic substitution is still being clarified and has led to renewed interest in acid-catalyzed exchange in heterocyclic compounds.122... 

The anhydrous tris-chelate complexes of aluminum perchlorate are stable beyond 300°C (669). Trialkylaluminums form colored complexes with bipyridyl and phenanthroline (109) which are five-coordinate monomers (681). 

Write the formulas for the following salts, by referring to Table 10-1 show the charges on the metal ion and on the complex anions sodium sulfate calcium silicate barium perchlorate beryllium carbonate aluminum nitrate aluminum sulfate aluminum phosphate potassium chlorate potassium sulfite. 

Free-ion attack is more likely for sterically hindered R. The ion CH3CO has been detected (by IR spectroscopy) in the liquid complex between acetyl chloride and aluminum chloride, and in polar solvents, such as nitrobenzene but in nonpolar solvents, such as chloroform, only the complex and not the free ion is present." In any event, 1 equivalent of catalyst certainly remains complexed to the product at the end of the reaction. When the reaction is performed with RCO+SbFg, no catalyst is required and the free ion" " (or ion pair) is undoubtedly the attacking entity." The use of LiC104 on the metal triflate-catalyzed Friedel-Crafts acylation of methoxy-naphthalene derivatives has been examined, and the presence of the lithium salt leads to acylation in the ring containing the methoxy unit, whereas reaction occurs in the other ring in the absence of lithium salts." Note that lithium perchlorate forms a complex with acetic anhydride, which can be used for the Friedel-Crafts acetylation of activated aromatic compounds." ... 

The primary use of hydrofluoric acid is for the decomposition of silicate rocks and minerals in the determination of species other than silica. In this treatment, silicon is evolved as the tetrafluoride. After decomposition is complete, the excess hydrofluoric acid is driven off by evaporation with sulfuric acid or perchloric acid. Complete removal is often essential to the success of an analysis because fluoride ion reacts with several cations to form extraordinarily stable complexes that interfere with the determination of the cations. For example, precipitation of aluminum (as AI2O3 XH2O) with ammonia is incomplete if fluoride is present even in small amounts. Frequently, it is so difficult and time-consuming to remove the last traces of fluoride ion from a sample that the attractive features of hydrofluoric acid as a solvent are negated. 

Uranium and Thorium in Phosphate. (72) These elements can be separated from a variety of phosphate-containing materials, e.g., fertilizers, bones, teeth, animal tissues, and wastes using this procedure. The sample is oxidized (if necessary), dissolved and placed in a nitrate or nitrate-perchlorate solution. To this solution, sufficient aluminum nitrate is added to complex the phosphate. This solution is then... 

Brosset (2), from measurements of the pH of aluminum perchlorate solutions, postulated that the product of hydrolysis of the aluminum ion is an infinite series of polynuclear complexes with the generalized formula Al[(OH)3Al]n3 Brosset, Biedermann, and Sillen (3) later recalculated Brosset s data and concluded that the major hydrolysis product could be either a single complex such as A16(OH)i53+ or an infinite series of complexes of the type Al[(OH)5Alo]n+3+w- Aveston, using ultracentrifugation, found evidence for either [Al2(OH)2]4+ or [Ali3(OH)32]7+. The latter species has been favored recently by Sillen (25) and by Johansson (26). 

Asymmetric reductions with chiral complex metal hydrides and tricoordinate hydride reagents are rare. Iminium salts25 26 and imines27 have been reduced by chiral complex aluminum hydrides. Optically active 2-substituted Ar-methylpiperidine was obtained by reduction of the corresponding 3,4,5,6-tetrahydropyridinium perchlorate with (—)-menthol lithium aluminum hydride. The optical purity for the -propyl derivative was 12% in favor of the S configuration. Similar reductions of imines prepared from acetophenone and propiophenonc with (-)-mcn-thol-lithium aluminum hydride and ( + )-borneol-lithium aluminum hydride reagents resulted in low (<10%) optical yields in those examples where optical yields could be calculated. 

Studies of the hydrolysis of perchlorate solutions of Al111 have found widely divergent interpretations, in part owing to the slowness in reaching equili-bria chloride solutions are even more complex Rftop-nt-st-iiHir.s sh w-t-lmt the above hydrolysis equation is too simple in the case of aluminum. Thus, a dimerization8,9 certainly occurs ... 

Calcium(II), which shows no appreciable complexing, has a distribution coefficient of 147 in 0.5 M perchloric acid and 191 in 0.5 M hydrochloric acid. Strelow, Rethemeyer and Bothma [3, 4] also reported data for nitric and sulfuric acids that showed complexation in some cases. Mercury(II), bismuth(III), cadrnium(II), zinc(II), and lead(II) form bromide complexes and elute in the order given in 0.1 to 0.6 M hydrobromic acid [5]. Most other metal cations remain on the column. Aluminum(III), molybdenum(VI), niobium(V), tin(IV), tantalum(V), uranium(VI), tungsten(VI) and zirconium(IV) form anion fluoride complexes and are quickly eluted from a hydrogen-form cation-exchange column with 0.1 to 0.2 M H F [6]. 

CgHgAgAlClu, Silver(I) aluminum chloride-benzene complex, 31B, 364 CgHgAgClOu, Silver perchlorate-benzene complex, 13, 530 22, 689 CgHgAlCl Cu, Benzene-copper(I) aluminum tetrachloride complex, 31B, 365... 

The reaction of dibenzeneruthenium(II) perchlorate with lithium aluminum hydride, however, yields a mixture of di-Ti-cyclohexadienylruthenium and (benzene)(cyclohexadiene) ruthenium(O). If sodium borohydride is used, the latter is the only complexed product obtained. [(ji-C5H5) Mo -(C6H,)]PF,- is easily reduced to the Mo(0) complex by lithium aluminum hydride, equation (6-39). 

Molecular sieves are used to remove water from hydrated salts or aqua-complexes. For example, [Mn(MeCN)6][C104]2 and [Fe(MeCN)6l[C104]2 are prepared from the corresponding aqua-complexes using molecular sieves.51/52 when zeolites are used in such dehydration processes, the reaction may proceed only slowly. Thus, hydrated aluminum perchlorate is transformed into [Al(Me0H)6][C104]3 using a zeolite in methanoP but the reaction takes six days. 

Phosphate precipitation of uranium (IV) is more selective. It is made from dilute hydrochloric or perchloric acid solutions. Separation is made from manganese, iron, vanadium and most other elements. Zirconium, thorium, and, to a smaller extent, titanium and tin precipitate.-Aluminum Interferes by the formation of soluble complexea with uraniiuii and phosphate lons. With sulfate and aluminum present, uranium is precipitated in a narrow pH-range around one. At higher pH, the soluble alumlnum-uranlum-phosphate complex is formed at lower pH, the soluble uranium-sulfate... 

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