Tris- aluminium

In Gegenwart von monomerem Aluminium-tri-tert.-butanolat wird die Ather-Bindung in THF gespalten... 

V.A. Montes, C. Li, R. Pohl, J. Shinar, and P. Anzenbacher Jr., Effective color tuning in organic light-emitting diodes based on Aluminium tris(5-aryl-8-hydroxyquinoline) complexes, Adv. Mater., 16 2001-2003 (2004). 

The only solid acidic catalyst which has given high polymers at an appreciable rate at low temperatures, and which has been studied in some detail, is that described by Wichterle [41, 42]. This was prepared as follows A 10 per cent solution in hexane of aluminium tri-(s- or t-butoxide) was saturated with boron fluoride at room temperature, and excess boron fluoride was removed from the precipitate by pumping off about half the hexane. Two moles of boron fluoride were absorbed per atom of aluminium, and butene oligomers equivalent to two-thirds of the alkoxy groups were found in the solution the resulting solid had hardly any catalytic activity. When titanium tetrachloride was added to the suspension in hexane, an extremely active catalyst was formed but the supernatant liquid phase had no catalytic activity. The DP of the polymers formed by the catalyst prepared from the s-butoxide was much lower than that of polymers formed with a catalyst prepared from the r-butoxidc. 

The synthesis of oxygen heterocycles in which cyclization onto a pendant alkyne is a key step has also been achieved. Reaction (7.36) shows an example of iodoacetal 29 cyclization at low temperature that afforded the expected furanic derivative in moderate Z selectivity [47]. A nice example of Lewis acid complexation which assists the radical cyclization is given by aluminium tris(2,6-diphenyl phenoxide) (ATPH) [48]. The (3-iodoether 30 can be com-plexed by 2 equiv of ATPH, which has a very important template effect, facilitating the subsequent radical intramolecular addition and orienting the (TMS)3SiH approach from one face. The result is the formation of cyclization products with Z selectivity and in quantitative yield (Reaction 7.37). 

The main starting point for thin-fihn low molecular weight materials was the work reported by Ching W. Tang and Steven van Slyke of Kodak in 1987, when they described the green electrolnminescence obtained from a thin film of vapour deposited aluminium tris(8-hydroxyquinoline) (Alq). ° Since that time the development of multilayer device structures and several new important classes of organic EL materials has led to snbstantial improvements and to the commercial development of display technologies based on this system. ... 

Aluminium tri-n-alkyls are dimeric in solution, although - especially for higher alkyls - the fraction of monomer can become significant at higher temperatures [ 19] in the gas phase they are usually monomeric. Kinetic evidence indicates that olefin insertion involves a monomeric aluminium trialkyl this suggests a Cossee-type insertion mechanism. Kinetic data do not indicate the presence of an intermediate olefin 7c-complex [23]. However, if the olefin complexation energy at the 7c-complex stage is low, this would be expected. 

Aluminium tri-terf-butoxide [556-91-2] M 246.3. Crystd from benzene and sublimed at 180°. 

The reverse reaction is known as the Oppenauer oxidation. Here aluminium tri tertiary but oxide and an involatile ketone such as cyclohexanone are used to oxidise any secondary alcohol to the corresponding ketone. 

Synthesis Morphine is hydrogenated over a palladium catalyst, and the resulting dihydromorphine is oxidized with benzophenone and potassium ferf-butoxide. Alternative oxidants are cyclohexanone with aluminium tri(feAf-butoxide) or aluminium triphenoxide (Rapoport, 1950 Pfister and Tishler (Merck Co), 1955 Kleemann et al., 1999). 

Another new LDA-based strategy for regioselective alkylation of unsymmetrical ketones involves the combined use of LDA and aluminium tris(2,6-diphenylphen-oxide) the latter complexes the less hindered side of the ketone, blocking the LDA and re-directing it by default to the more hindered side.154... 

A new method of kinetically controlled generation of the more substituted enolate from an unsymmetrical ketone involves precomplexation of the ketone with aluminium tris(2,6-diphenylphenoxide) (ATPH) at —78°C in toluene, followed by deprotonation with diisopropylamide (LDA) highly regioselective alkylations can then be performed.22 ATPH has also been used, through complexation, as a carbonyl protector of y./)-unsaturated carbonyl substrates during regioselective Michael addition of lithium enolates (including dianions of /i-di carbonyl compounds).23... 

A good mediator for the hetero Diels-Alder reaction of aldehydes is the bulky, oxygenophilic aluminium tris(2,6-diphenylphenoxide) (ATP) 2-19 developed by Yamamoto [78] which allows the differentiation between two sterically discriminated aldehydes. Thus, reaction of a mixture of 2-10,2-16 and 2-17 in the presence of 2-19 gave nearly exclusively 2-15, whereas in the presence of BF3-OEt2 a 1.3 1 mixture of 2-15 and 2-18 was formed (Fig. 2-5). 

Figure 4.2 Absorption and emission spectra of aluminium tris (quinolate) [Alq j.

Aluminium Tris-[trimethylsilyl-methyl]- (Diethyletherat) XIII/5, 75... 

Aluminium tri-isoamyl is a liquid, boiling about 250" C. at 80 to 100 mm. vapour density determinations indicate the formula to be... 

Different phases of alumina may be prepared by calcination of aluminium tri-hydroxldea (gibbalCe and bayerite) or oxy hydroxides (boehmlte and... 

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