Cyclopentadienide salts, substituted

Diazocyclopentadienes react with methyl lithium or phenyl lithium to form azo-substituted cyclopentadienide salts [56,57,74]. Protonation of these salts gives rise to cyclopentadienone hydrazones e.g. 

FIGURE 7.25. Chemical structure of the penta-substituted fullerene potassium salt. In the present work, only the compound with R = CgHs has been studied. A bilayer vesicle model, consisting of Noaia = 6693 molecules in an outer shell of radius i outer = 517.6 nm plus AIjnner = 5973 molecules in an inner shell of radius Sinner = 16.7 nm. A sector has been cut out for clarity. The hydrophobic fullerene bodies are shown in green, the hydrophilic charged cyclopentadienide regions are in blue, and the five substituents are schematically represented as yellow sticks. 

Regioselective syntheses of members of the 2- (41) and 4-series (40) are achieved by nucleophilic substitution of 2- or 4-halo- or -methoxy/phe-noxypyridinium salts with sodium cyclopentadienide (60JA3793,60MI253 63JCS253 64TL3087) (Scheme 13). 

The reaction of the l-(diaminocyclopropenyliumyl)pyridinium dication 30 with two equivalents of potassium pentakis(methoxycarbonyl)cyclopentadienide (31) also afforded the ionic salt 32 of 1 2 composition, whose structure was determined by X-ray crystallography. On the other hand, the reaction of 30 with the lithium salt of the 7,7,8,8-tetracyanoquinodimethane adical anion 33 resulted in covalent bond formation giving the substituted bis(cyclo-propenylium) dication 34. °... 

In a chiral approach to ferrocenyldiamines, various aryllithiums, in the presence of sparteine, and in toluene, were added to 6-dimethylaminofulvene, leading to chiral lithium cyclopentadienides. The latter can be transformed into fer-rocenes, via an Fe(II) salt. When the arylhthium is ortho-substituted by a methyl, and in the presence of a chiral binaphthyl alcoholate, instead of sparteine, the ratio of chiral to meso-ferrocene is 88/12 (in 94% yield) and the chiral one is almost pure (ee>99%) (Scheme 31) [52]. 

This salt appears to be stable indefinitely in air. It is unattacked by bromine, hydrogen bromide or hydrogen iodide, [34], but is nitrated by dinitrogen tetroxide or by nitric acid in acetic anhydride [35]. Other examples of substituted cyclopentadienide anions which can be handled in air include aroyl-, [20-22], fomyl-, [36], methoxycarbonyl-, [24,37-40], cyano-, [41-44], and methyl-sulphonyl-cyclopentadienides [45]. 

Calicene itself has not been described,but a number of substituted derivatives are known. Methods for their preparation include reactions of cyclopentadienide ions with cyclopropeirtum salts or with 3,3-dihalogenocyclopropenes, e.g. [257-259] ... 

Thallium(I).- All the chemistry here concerns cyclo-pentadienyl ligands. Thallium salts of the substituted species T1 (t -C5H4X) [X = C(0)Ph,224 pph2 ] have been prepared from the sodium cyclopentadienide and TlOEt. The former has been used in the synthesis of various transition metal species e.g. 

The reaction of alkali metal cyclopentadienides with metal salts is generally applicable to the synthesis of substituted metalcyclopentadienyls. Thus, sodium methylcyclopentadienide readily reacts with metal halides to... 

Treatment of the sulphonium chloride (15) with thallium cyclopentadienide gives the bis(dimethylsulphonio)cyclopentadienide (16), isolated as the perchlorate the tri-substituted salt (17) has also been obtained/ ... 

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