Cyclopentadienide, potassium

The cyclopentadienes la-e can be deprotonated by potassium in toluene to give the potassium cyclopentadienides 2a-e [2]. These compounds are very soluble in THF and also in hot benzene or toluene, which is indicative of the presence of essentially monomeric units in solution this is due to an intramolecular donor stabilization by the tentacle function [6]. 

Bis[(tris(isopropyl)cyclopentadienyl)]zinc (Zn C5(Pr1)3H2 2, 21) and bis[(tetrakis(isopropyl)cyclopentadienyl)]zinc (Zn C5(Pr1)4H 2, 22) were synthesized from the respective potassium cyclopentadienides and zinc iodide as shown in Scheme 18.50 The same slipped sandwich compounds were also isolated from zinc-reduced VC13 solutions when they were treated with these alkali metal cyclopentadienides at room temperature.51 The outcomes of these reactions suggest that zincocenes are likely intermediates in the syntheses of transition metal metallocenes, in which the metal halides have been pre-reduced with zinc. The solid-state structure of Zn G5(Pr1)4H 2 is shown in Figure 10. The sole... 

Methyl-3-buten-1 -ynyltriethyHead, 3413 Methylcopper, 0440 Methylenedilithium, 0401 Methylenemagnesium, 0402 Methyllithium, 0452 Methylpotassium, 0448 Methylsilver, 0421 Methylsodium, 0463 Octylsodium, 3053 Pentamethyltantalum, 2046 Potassium cyclopentadienide, 1846 Propylcopper(I), 1251 Propyllithium, 1253 Propylsodium, 1269... 

The tris cyclopentadienide complex of uranium was first prepared by the direct reaction of uranium trichloride with a benzene suspension of potassium cyclopentadienide. More recently it has been prepared by the reduction of tetra-... 

This is remarkable, since the reduction potential of Th(IV) to Th(III) recently has been estimated as —3.7 volts 73) and direct reduction of U(C5H5)4 and Pu(C5Hs)3 with potassium metal produces the actinide metals. The ei/z for naphthalene in acetonitrile is —2.63 V (nearly the same as the aLkaJi metals). Since this is much smaller than the Th(IV) to Th(III) reduction potential, it would seem to imply substantial stabilization of the +3 state by cyclopentadienide. The observed room temperature magnetic moment of Th(C 5115)3 (0.403 BM) is consistent with the Th(III) (5/ ) assignment. Thorium triscyclopentaxhenide is similar in behavior to U(C5H5)3, forms adducts with both THF and cyclohexyhso-nitrile and has been shown to be isostructural with the other tris (cyclopentadienyl) actinides and lanthanides. 

The preparation of Th, U and Np tetracyclopentadienides were accomplished by the straightforward reaction of the anhydrous metal tetrachloride with potassium cyclopentadienide in benzene (6). Tetrakis(cyclopentadienyl) pro-tactinium(IV) was prepared using Be(CsH5)2 and Pads prepared in situ (6). Infrared data suggest that aU of the tetracyclopentadienides possess similar molecular structures the Th, U and Np complexes were found to be isostmctural by powder techniques (79, 80). 

Methylbismuth oxide, 0427 Methylcopper, 0439 Methylenedilithium, 0400 Methylenemagnesium, 0401 Methyllithium, 0451 Methylpotassium, 0447 Methylsilver, 0420 Methylsodium, 0462 Octylsodium, 3048 Pentamethyltantalum, 2040 Potassium cyclopentadienide, 1840 Propylcopper(I), 1247 Propyllithium, 1249 Propylsodium, 1265... 

Poly(difluorosilylene), 4324 Potassium antimonide, 4668 Potassium terf-butoxide, 1645 Potassium cyclopentadienide, 1840 Potassium diethylamide, 1679 Potassium octacyanodicobaltate(8—), 2875 Potassium—sodium alloy, 4641... 

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. 

Methyl lithium and butyl lithium are widely used for the synthesis of other organolithium compounds. For example, lithium cyclopentadienides are generally prepared by the reaction of the cyclopentadiene with butyl lithium. In contrast, the amido-alkali metal compounds are becoming increasingly important in the synthesis of organoalkali metal compounds with the heavier alkali metals. For example, l,2,4-tris(trimethylsilyl)-l,3-cyclopentadiene reacts with potassium bis(trimethylsilyl)amide to form potassium l,2,4-tris(trimethylsilyl)cyclopentadienide. ... 

Treatment of CpjLn [Cp" = l,3-bis(trimethylsilyl) cyclopentadienide Ln = La, Ce, Pr, Nd] with 2 equiv. of 18-crown-6 and 2 equiv. of potassium in benzene affords lanthanide complexes with CgHg dianions. The molecular... 

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