Acetylacetone alkali metal complexes

Other complexes described by the early workers include salicyl-aldehyde, o-nitrophenols, and acetylacetone as possible neutral ligands, HL, so that compounds of composition ML, HL or ML, HL were obtained. These were referred to as acid salts and illustrate the difficulty of deciding on a criterion for complex formation. Sfieakman (5)has reviewed the crystal structures of many acid salts of alkali metals in an investi-... 

Lanthanide aryloxides have proved to be excellent precursors to homoleptic lanthanide alkyls (B, Eq. 13) [140], The reaction can be conducted in non-polar solvents because of the good solubility of the starting compounds. The formation of insoluble alkali metal aryloxides is the driving force (kinetic control). Complexes derived from aliphatic alcohols [141] and acetylacetonates [131] are... 

Since 1958 substantial progress has been made in understanding the complicated electronic spectral properties of acetylacetonate complexes. The acetylacetonate anion and alkali metal ( ionic ) acetylacetonates exhibit a single, intense (e 10 ) and nearly symmetric band near 34.500 cm i. Molecular orbital calculations of both the Huckel- and self-consistent field — LCAO tjq>es (52, 53) lead to the assignment of this band as a re-re transition. (A second high-energy re-re transition (res—res or res—re4) is predicted but apparently occurs outside the normal ultraviolet region.)... 

Admittedly, the above is a considerable simplification of what is a complex, multi-variable process, but some frame of reference seems required. The use of a quaternary ammonium salt instead of an alkali metal cation allows for the dissolution of ammonium enolate ion pairs in nonpolar media [54]. Whereas these ion pairs are relatively dissociated in such solvents as DMSO and give appreciable amounts of 0-alkylation, in benzene or toluene, the C/0 ratio is quite high. Brandstrom and Junggren found that isopropylation of tetrabutylammonium acetylacetonate lead to a C/0 ratio of 0.72 in DMSO and 13.8 in toluene solution (see Eq. 15.17) [54]. 

As homogeneous catalysts, alkali metals. Li —amide,and transition metal complexes such as Ni[P(OC2Hs)3]4, Ni acetylacetonate, PdBr2(Ph2PCH2PPh2),... 

The volatility of the j8-diketonate complexes can also be increased by formation of the tetrakis complexes, because the latter are mononuclear. The first volatile heterobimetallic compound was the ionic Cs[Y(hfac)4], which Lippard (1966) sublimed without decomposition both in air and in vacuum. Addition of alkali metal acetylacetonate to [R(acac)3] complexes results in the formation of volatile M[R(acac)4] complexes (M = Li, Na, Cs) (Zaitseva... 

In solution, the monomer of anhydrous Co (AA) 2 apparently is tetrahedral (12), It is reasonable to expect that the monomeric j3-ketoenolate complexes of the alkali earth metals as well as manganese(II), iron(II), zinc(II), cadmium(II), and lead(II) also will be tetrahedral (18). However, in the solid state the manganese(II), iron(II) (19). and zinc(II) (6) complexes with acetylacetone apparently are polymerized (18). The cation B(AA)2" very likely also contains a tetrahedral BO4 unit. 

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