Alkali metal compounds

A. E. Halasa in A. W. Langer, ed., Polyamine-Chelated Alkali Metal Compounds, ACS Advances in Chemisty, No. 130, American Chemical Society, Washington, D.C., 1974. 

Simple allyl alkali metal compounds have only a small capability for discriminating between diastereotopic faces of carbonyl compounds. Although a matter of simple diastereoselectivity, this can be concluded from the reaction of conformationally locked 4-/erf-butylcyclohexanone... 

Generally, in the nucleophilic addition to carbonyl groups, either magnesium compounds or alkali metal compounds (such as the Li, Na and K derivatives) are used. In some cases even potassium carbonate or piperidine were used as the base for condensation with sulfones. Good results were obtained when concentrated aqueous NaOH was used under phase-transfer conditions288,297,333. 

Some of the results of bulk polymerization of 61 by using different anionic catalysts are summarized in Table 858 It was easily polymerized in the presence of alkali metal compounds above 60 °C. The polymerization at 150 °C was too fast to be controlled. The yield and the viscosity number, i gp/c, of the resulting polyamide increased with the reaction time. The initial rate of the polymerization became higher with the size of the countercation, in analogy to the case of anionic polymerization of e-caprolactam59. The rate increased also with raising temperature as shown in Fig. 658. ... 

First reported by Fredenhagen in 1926 F3, F4), the graphite-alkali-metal compounds possess a relative simplicity with respect to other intercalation compounds. To the physicist, their uncomplicated structure and well defined stoichiometry permit reasonable band-structure calculations to be made S2,12) to the chemist, their identity as solid, "infinite radical-anions frequently allows their useful chemical substitution for such homogeneous, molecular-basis reductants as alkali metal-amines and aromatic radical anions N2, B5). 

G4, Z1). Sodium reacts to form C Na, although ternary systems with other alkali-metal compounds are known (A3, B6). 

Scheme 1 Graphical representation of various aggregation modes in alkali metal compounds.

Whatever the best explanation may be, an indication that allylic alkali metal compounds or allylic carbanions do in fact form the less stable of the two possible acids on neutralization is found in the results of the reduction of aromatic compounds by dissolving metals.376The detection of a paramagnetic intermediate in a similar system and polaro-graphic evidence indicate a one electron transfer in the rate and potential determining step.878 376 The mechanism therefore involves ions (or organometallic intermediates) like the following ... 

Nitrates, acetates, and alkali metal compounds are water-soluble. Zn(N03)2, Pb(C2H302)2, and Nal are soluble. Most halides are soluble in water CuCl2 is soluble in water. Although most sulfates are soluble in water, BaSO s) is not soluble in water. Only a few hydroxides are soluble in water Al(OH)3(s) is not soluble in water. 

Alkali metal compounds Li, Na, K, Rb, Cs All soluble Some complex (ternary) alkali metal salts... 

There is a limited number of examples of preparations involving the reaction of stannyl-alkali metal compounds with a substituted heteroarene, for example, Equations (58)-(60).88,197,198 Some of these reactions (e g Equation (58)) occur only with photoirradiation, showing that they involve SRN1 processes, but others may be straightforward nucleophilic heteroaromatic substitutions. 

The high melting points of the compounds of the noble metals may be noticed. With elements of the groups from Ag to Te, alkali metal compounds are formed... 

Margerison, D. Newport, J. P. Trans. Faraday Soc., 1963,59, 2058-2063. See also Langer, A. W. "Polyamine-Chelated Alkali Metal Compounds" American Chemical Society Washington. D.C.. 1974 Advances in Chemistry Series No. 130. 

Although the heavier alkali-metal compounds of the oxides of manganese, cobalt, chromium, and... 

Hence measurements have been made on unsubstituted allyl alkali-metal compounds, and also on neopentylallyl (I, 5,5-dimethylhexen-2-) and neopentylmethallyl (II, 2,5,5-trimethyl-hexen-2-) alkali-metal compounds which are models of the polymerizing chain end in the anionic polymerization of butadiene and isoprene respectively. 

The allyl alkali-metal compounds give 2 line C-13 nmr spectra. The terminal positions are equivalent either because of rapid equilibrium between two covalent structures, or because the structure is a delocalized symmetrical ion. The chemical shifts and C-C coupling constants are recorded in table I. Reasonable agreement with literature 6 values are found (8, 2). 

C-13 nmr spectra were taken of all the alkali metal compounds of I and II from Li to Cs. As expected, changing the counter-ion had very little effect on the chemical shifts of the carbons in the neopentyl group in either I or II, or on the extra methyl group in II, compared with the parent hydrocarbon ( 3). 

If the allyl alkali metal compounds are ionic compounds, then if the allyl ion is delocalized the terminal carbons would be equivalent and contain most of the charge, and all three... 

Studies on benzyl alkali metal compounds, models of styrene anionic polymerization systems, showed coupling constants to the enriched a carbon in the above ranges, showing it to be sp hybridized (ll). Little effect of the charge could be detected in the Jg c values, although it should be noted that the charge is extensively delocalized into the benzene ring. 

In the present study, the Jg g values in the allyl alkali metal compounds are near 60 hz for the K and Cs compounds, and a little lower for the Li compound, table I. Allyl mercury is not a delocalized system, and if any exchange occurs between the two ends of the allyl radical it is slow on the NMR time scale. Consequently and Jg Y are measurable and are h2 and 69 hz... 

Free energies AG have been reported for the rotational barriers in allyl alkali metal compounds (set CPI, Table 10) . As the only variable is the alkali metal ion, the AG values were correlated with equation 45 ... 

The extensive use of alkyllithium initiators is due to their solubility in hydrocarbon solvents. Alkyls or aryls of the heavier alkali metals are poorly soluble in hydrocarbons, a consequence of their more ionic nature. The heavier alkali metal compounds, as well as alkyllithiums, are soluble in more polar solvents such as ethers. The use of most of the alkali metal compounds, especially, the more ionic ones, in ether solvents is somewhat limited by their reactivity toward ethers. The problem is overcome by working below ambient temperatures and/or using less reactive (i.e., resonance-stabilized) anions as in benzylpotassium, cumylcesium and diphenylmethyllithium. 

Band structure cesium auride, 25 240-241 graphite-alkali metal compounds, 23 287 Band theory, for one-dimensional electrical Conductors, 26 237-241 Barbituric acid, 18 187 Barium... 

---