Alkali metal complexes phosphines

With very few exceptions, alkali metal complexes of phosphinomethanide ligands are synthesized by the deprotonation of a tertiary phosphine bearing an -CHR2 group with an alkali metal alkyl such as BunLi ... 

The low affinity of the alkali metals for neutral P-donor ligands has hampered efforts to synthesize complexes in which there is a genuine R3P-M interaction (see Section I). However, this poor affinity may be overcome by incorporating a remote phosphine functionality into a potentially chelating anionic ligand, such as a phosphine-substituted alkoxide, amide, or aryl, and several alkali metal complexes of such ligands have been isolated. 

Selected Structural and NMR Data for Crystallographically Characterized Alkali Metal Complexes of Tertiary Phosphine-Functionalized Ligands... 

Adenosine triphosphate alkali metal complexes, 34 vanadyl complexes, 568 Alane, 123 amine adducts, 107 phosphine adducts, 111 Alane, alkoxy-, 124 Alane, amino-, 109 Alane, imino-, 109 Alkali metal complexes, 1-70 acid anions, 30 acid salts, 30 bipyridyl, 13 crown ethers cavity size, 38 cryptates... 

Resonance structures (7.156b) have been postulated for phosphine di(imino) anions, and alkali metal complexes such as (7.156c) have been studied [34]. 

The counterion is quite important to the outcome of this reaction. Ion pairs, which form between alkali metal ions and the complex, induce CO lability which aids in the substitution process.1 1 Large charge-delocalized cations such as PPM are much less effective in forming ion pairs. The sulislilution process shown in Eq. 15.95 occurs readily when the counterion is Na but foils when it is PPN. Another good example of this effect can be seen by comparing NaICo CO)J and PPN [ Co[Pg.356]

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