Stacked structure, organolithiums

Organolithium compounds, 2 69 ring stacking, 37 82-92 systems capable of, 37 82-83 uncomplexed, structure, 37 53-54 X-ray crystal structure, 37 48 Organomagnesium halides, 2 71 Organomercury compounds, see Mercury, -carbon compounds Organometallic complexes... 

E. Ring Stacking General Applications to the Structures of Organolithium Compounds... 

Fig. 3. Structural options for uncomplexed organolithiums (a) infinite stack of (LiX)2 rings, (b) infinite ladder of (LiX)2 rings, (d) hexamer, a limited stack of two (LiX>3 rings, (e) tetramer, a limited stack of two (LiX)2 rings, and (f) isolated (LiX)4, (LiX)3, and (LiX)2 rings. For contrast, (c) illustrates a segment of an infinite three-dimensional lattice, X being an inorganic atomic anion such as CK.

The crystal structures of numerous organolithium compounds and complexes with 0—Li bonds are now available (2-5). Table IV lists a number of these species, as well as two derivatives of heavier alkali metals. As with the C—Li derivatives just discussed (Tables II and III), clustered (ROLi) tetramers and hexamers, as well as ring dimers, are prevalent. Note that (OLi)2,3 ring systems also are pseudoplanar (Fig. 21a). However, extensive stacking leading to polymers will only occur if the substituents on 0 are small and if polar ligands are absent. Otherwise, limited (double) stacks or unstacked rings form. 

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