Lithium compounds, structure

The compound [Li(Tp )(Hpz )]-Hpz is the unique reported lithium compound, structurally characterized, containing a homoscorpionate ligand. It shows a UN4 distorted tetrahedral geometry with a triden-tate Tp (Fig. 2.1). The crystal packing is dominated by hydrophobic methyl-methyl interactions.1... 

Structures of Organonitrogen-Lithium Compounds Recent Patterns and Perspectives in Organolithium Chemistry... 

Two main structural types have been identified for allyl alkali metal species solvated ions in the form of CIPs where a delocalized anion with metal coordination is perpendicular to the ligand plane,130-134 or unsolvated allylic lithium compounds displaying localized ligand systems with NMR spectra closely resembling those of alkenes.135-138... 

About structures of lithium compounds LisMeFs we have but rare knowledge. Klemm, Brandt and Hoppe (193) report in accordance with Meyers and Cotton (225) that the x-ray-diagrams of the cobalt compound LisCoFe were of a poor quality. The polymorphism that Carton and Wanklyn (108) report of the aluminium compound LisAlFe points to a more complicated situation in this ternary fluoride. The sizes given of the unit cells do not show any simple relation to the cryolite cell. The same may be true of compounds LisMeFa of the transition metals. 

The high selectivities found in the protonation experiments of the nitronate ions 44 suggested that also allyl anions 54 can be regioselectively protonated by a general acid protonation. Therefore, some lithium allyl compounds (Structures 6) were generated by deprotonation of alkenes with n-butyl lithium. 

These drugs are most commonly classified according to their principal pharmacological effect rather than by specific chemical structure (Table 10.4). The exception to this is the tricyclic antidepressants which share a common chemical structure and also common pharmacological effects. The other important type of drug used in the treatment of mood disorders is the mood stabilisers (lithium compounds and some anticonvulsants) which are discussed in the next section of this chapter. Tricyclic antidepressants... 

N.M.R. studies on diene models show that the preferred configuration of the lithium compound in hydrocarbons is trans although some cis structure does exist, in equilibrium i.e. the active center itself does exist in two forms (9,10). 

STRUCTURES OF ORGANONITROGEN-LITHIUM COMPOUNDS RECENT PATTERNS AND PERSPECTIVES IN ORGANOLITHIUM CHEMISTRY... 

For the above reasons, organolithium compounds and complexes have been termed supramolecules [ complex molecules held together by noncovalent bonds (4) ]. What we have here are ionically bonded (at least as far as the central metal-organic anion linkages are concerned) yet often discrete molecular species. Most of their physical properties reflect their limited aggregation and their organic peripheries. These points are stressed in Fig. 3, a schematic presentation of the major structural types of uncomplexed organic lithium compounds. 

Fig. 4, Lithium compounds exhibiting short Li-H—C contacts in the solid state (a) representations of (MeLiL, and of the intercubane contacts found, (b) Li—H3C and Li—HjC contacts found in (LiBMe,i, and (c) part of the structure of (cyclohexyllithium)6, and Li—oHC, —ffHC contacts found over its li3 faces.

The above discussion of the types of organic lithium compounds, their synthetic uses, and the structural and bonding features they possess sets the scene for the bulk of the review. Here we turn our attention specifically to the structures of NLi compounds. 

---