Alkyl and aryl metal amide

In Section II, the structures of alkyl and aryl metal amides of the metallic elements Mg, Ca, Sr, Ba, Al, Ga, In, and T1 are briefly discussed from a general point of view. Some analogous compounds of other elements are included for comparison. 

STRUCTURAL ASPECTS OF ALKYL AND ARYL METAL AMIDES... 

Salt metathesis [Eq. (7)] is a well-established route in the synthesis of a variety of alkaline-earth metal alkyls [186,208-210], allyls [211-214], benzylates [149,178], cyclopentadienides [17, 108, 215-219], pentadienyls [220], fluorenyls [17, 221], indenyls [222], amides [112, 113, 223], p-diketiminates [112], guanidinates [15, 194], aUcoxides [224], aryloxides [224], silanides [210, 225-228], thiolates [229], phosphanides [230, 231], selenolates [229], and germanides [232, 233]. However, the route has been rarely used for the synthesis of more reactive alkyl and aryl metal complexes, largely due to issues pertaining to ether cleavage chemistry as metathesis typically requires the presence of an ethereal solvent. 

The compounds (r/-CsHs)3UCl and (r/-CsHs)3ThCl are useful precursors for the synthesis of a large number of organoactinides, such as tris(cyclopentadienyl)metal alkoxides, tetrahydroborates, alkyls and aryls, halides, amides, and other derivatives,The chlorouranium compound was first synthesized by Reynolds and Wilkinson in 1956 from uranium tetrachloride and sodium cyclopentadienide in tetrahydrofuran. Vacuum sublimation, in our hands, invariably gives the pure product in low yield. The thorium analog was originally prepared in a similar manner,... 

The anionic polymerization of epoxides such as ethylene and propylene oxides can be initiated by metal hydroxides, alkoxides, oxides, and amides as well as metal alkyls and aryls, including radical-anion species such as sodium naphthalene [Boileau, 1989 Dreyfuss and Drefyfuss, 1976 Inoue and Aida, 1984 Ishii and Sakai, 1969]. Thus the polymerization of ethylene oxide by M+A involves initiation... 

Alkyl- and Aryl-Substituted Main-Group Metal Amides... 

Subsequent work revealed that the ylid mechanism was induced by metal alkyls and aryls but not by metal alkoxides and amides ". Stereochemical evidence was cited, metal alkyls giving more c/s-cyclooctene and metal amides and alkoxides more trans-cyclooctene for elimination from cyclo-octyltrimethylammonium ion (49). Elimination from cyclooctyldimcthyl-(bromomethyl)ammonium ion with methyl lithium gave the same predominance of the c(i-cyclooctene. 

Tetranuclear copper complexes have tetrahedral, square-planar, or butterfly structures. The compound Cu4 (Pr 0)2PS2 4 has a distorted tetrahedral skeleton of the metal atoms with one sulfur atom symmetrically bonded to two copper atoms, while the other sulfur atom forms a bond with the third copper atom. Copper and silver form many clusters containing alkyl and aryl ligands (See Chapter 4). The complex Cu4(CH2SiMe3)4, like Cu4 N(SiMe3)2 4, has a square-planar structure with bridging alkyl ligands. In the alkyl compound, in contrast to the amide one, there are Cu —Cu bonds. 

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