Pentaaryl

Stable tetra- and pentaaryl-l,3-oxazepines 4 are formed in good yield when the corresponding pyridine 1-oxides are irradiated the products are accompanied by small amounts of the... 

There are limited number of reports of the observation and isolation of functionalized fullerene cations. The monoalkylated [RC6o+(73,74), C12CH-C70+ (75), and (EtO)2P+(OH)CH2-C60+ (76)], monoprotonated [HC60+ (7-2,77)], and pentaarylated [Ar5C60+ (75)] fullerene cations have thus far been prepared as stable solutions or isolated as solids (Figure 1). 

A comparable addition pattern with as many as five attached groups allowing further functionalization is represented in pentaaryl-fullerenes like 25-27 (Troshina et al., 2007 Zhong et al., 2006). Whereas the free acids are virtually insoluble in pure water, the use of basic water in the case of 25 (Zhong et al., 2006) and conversion of the polyacids 26 and 27 to the corresponding potassium salts leads to stable aqueous solutions with high fullerene concentrations. 

Die Cyclisierung von N,N -Diaryl-N-(l,2-diaryl-2-oxo-ethyl)-benzamidin-Hydrochloriden mit Thionylchlorid fiihrt in Ausbeuten von 97-99% zu den entsprechenden Pentaaryl-imidazo-lium-Salzen (insgesamt 17 Beispiele)343 z,B. ... 

Birkett and co-workers506 have applied a different approach using chloride abstraction with A1C13 from Ar5C6oCl to generate pentaarylated fullerene cations... 

The arylation of cyclopentadiene (3) with 2-chlorobromobenzene using tris(7ert-butyl)phosphine as ligand leads to a mixture of the tetra-arylated product 5e and its pentaarylated congener, both isolated in 17-18 % yield. With the less reactive ortho-dichlorobenzene the process stops at the stage of the triarylated species 4e, which can then be further arylated with 2-chlorobromobenzene. 

Pentamethylantimony is also generated in the reaction of pentaaryl-stiboranes with methyllithium mixed species are the intermediates (54) ... 

The photolysis of some tetraaryl- and pentaaryl-pyridine N-oxides 150 (in benzene solution, in a Rayonet photoreactor by using 3500, 3000, and 2537 A lamps) allows the isolation ofhigh yields of the corresponding 1,3-oxazepines 151, the structures of which have been confirmed using X-ray crystallography for 151f (Scheme 12.39) [95]. 

Recent Developments in the Field of Pentaaryl Antimony Compounds... 

Die Thermolyse spirocyclischer Pentaaryl- und Alkyl-tetraaryl-phosphorane fiihrt bei kleinem Rest R zu tert. Phosphanen der Phosphonan-Reihe (S. 907), bei gro8em Rest zu tert. Phosphanen mit 2,2 -Biphenyldiyl-Geriist (s.S. 893) l7,2l ... 

Thermolysis of sulfmate derivatives Ph4,Sb0S(0)R has been reported to give Ph SbR in refluxing benezene (equation 196 ). By this method, however, unsymmetrically substituted compounds in pure form may not be obtained because a redistribution reaction between the mixed pentaaryl compounds takes place even at ca 60 °C (equation... 

Three types of pentavalent arylbismuth derivatives can be used for the arylation of phenols. They derive from the triaryl, the tetraaryl and the pentaaryl series. The C-arylation of phenolic compounds can be performed by triarylbismuth carbonate, the presence of a base being not mandatory. It can also be realized by a variety of pentavalent triarylbismuth compounds and tetraarylbismuthonium salts, both in the presence of a base, in various solvents (methylene chloride, benzene, toluene or... 

Pentaaryl- and pentaalkylbismuth compounds are converted by aryl- or alkyllithium reagent to the corresponding hexaaryl- and hexaalkylbismuthate complexes, respectively, at low temperatures [931C3948, 94AG(E)976] (Scheme 3.7). 

Figure 2.52 In a Friedel-Crafts-like reaction, the hexachlorofullerene CeoCis may be converted into a pentaarylated product.

Structure. Bonding and Ligand Reorganization - Several pentaaryl bismuth compounds (3) have been synthesised by the conventional reaction of (1) with arylithium (2) and three were characterised by single-crystal > ray structure analysis. In contrast to pentaphenylphosphorus (and AsPhs) which are trigonal bipyramids, the bismuth compounds exhibit almost ideal square pyramidal geometry. 

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