Heterometallic Potassium Amides

The inverse crown ether-type structure described previously for bis(alkali metal) 

The complex [ ((Me3Si)2N)4K2Mg2(O2) ] obtained from KBu, Mg Bui and (Si-Me3)2NH is similar to the related heterobimetallic compounds [ (Me3Si)N 4Li2M-in that it 

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Further examples of a cyclic heterometallic potassium amide, obtained from KBu, MgBu2 and tmpH in CgH, or PhMe, are the isostructural complexes [(tmp)i2K6-Mg6(C6H5)6] (Figure 2.8) and [(tmp)i2K6Mg6(C6H4CH3)6] comprised of 24-membered N22K6Mg6 macrocycles that play host to six mono-deprotonated arene molecules... 

An important class of alkali and alkaline earth metal amides are Mulvey s inverse crown complexes (also discussed in Chapter 2, dealing with sodium and potassium amides), in which cationic homo- or heterometallic macrocycles are hosts to anionic guest moieties.The term inverse crown indicates that the Lewis acidic/Lewis basic sites are reversed or exchanged in comparison to conventional crown ether complexes. Scheme 3.9 illustrates the range of recently published alkali and alkaline earth metal amide inverse crown complexes (for related Zn species see Chapter 7 on group 12 amides). 

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