Dipivaloylmethane

Picolinate (pic) Acetylacetonate (acac) Dipivaloylmethanate (dip) N-methylsalicylimine (sal) SCHEME 3.78 Chemical structures of some bidentate and monoanionic ancillary ligands. 

The dimeric dialkoxy-bridged compounds [L2FeOR]2 (L = enolate of acac or dipivaloylmethane R = Me, Et, or Pr ) have been prepared by the oxidation of Fe compounds in alcoholic solutions containing the free ligand and base or directly from Fe compounds. The structure (57) is proposed. ... 

Complexes of acetylacetone (acacH), benzoylacetone (bzacH) and dipivaloylmethane (dpmH) have been reported. The acetylacetonate [Cr(acac)2] has been prepared from chromium(II) acetate and acetylacetone.142,143 It can also be obtained by the addition of aqueous sodium acetylacetonate to an aqueous solution of chromium(II) chloride, but in any preparation the yellow solid must be filtered off and dried as rapidly as possible, otherwise the chromium(III) compound is obtained. Its magnetic moment is 4.99 BM at room temperature consistent with a high-spin d4 configuration. 142The powerful reducing ability of [Cr(acac)2] has been used to prepare iron(II) and chromium(II) complexes80 of porphyrins and related ligands. 

Diketonato complexes of the dibenzostib(V)ole ring system have also been reported. These are formed when 5,5,5-trichlorodibenzostib(V)ole are reacted with acetylacetone or dipivaloylmethane. The two stereoisomers (71) and (72) are formed and are in equilibrium with each other (equation 15) (78JOM(160)435). 

The main problem here is to obtain suitable coordination compounds that can be vaporized at reasonably low temperatures at which they are thermally stable. To this end a great deal of work has been published on the gas chromatography of (3-diketone complexes such as (61 R2 = H) 93 Volatile complexes of the rare earths with dipivaloylmethane (61 R1 = R3 = CMe3 R2 = H) were first prepared in 1965 but while the separation of pairs of neighbouring metals (e.g. Eu and Sm) has been reported, the complete separation of the whole group has not been successfully achieved. Attempts to use columns longer than 70-75 cm result in peak-broadening and inefficient separation.94... 

The replacement of methyl groups on acetylacetone by /-butyl groups causes a massive increase in steric hindrance to electrophilic substitution. The chromium(III) chelate of dipivaloylmethane can be chlorinated and nitrated only very slowly by means of forcing conditions (equation 68).281... 

The most commonly used shift reagents are tris-chelates of lanthanide ions with the (i-diketones, 2,2,6,6-tetramethylheptane-3,5-dione (dipivaloylmethane, (1)) and l,l,l,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione (2). Typical reagents are tris-(dipivaloylmethanato) europium and tris-1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionato europium, the names of which are normally abbreviated to Eu(dpm)3 and Eu(fod)3. 

N-Donors. NNN N -Tetramethylethylenediamine and a range of P-diketones (e.g. acacH, hfacH, dipivaloylmethane) form [Cu(tetren)(P-diket)]X,nH20 (X = C104 or N03), which have been examined spectroscopically to establish the effect of the various substituents upon the observed spectra.674... 

Acetylacetonates, which have delocalized electronic Ji-systems including the atoms 02C3, form five-atomic chelates. Dialkyldigallium compounds (109 and 110) containing these ligands terminally attached to both Ga atoms of the Ga-Ga bonds are easily available by the reaction of dibenzoyl- or dipivaloylmethane with 53 similar to the reactions of the carboxylic acids shown in Eq. (19).185,186 Centrosymmetric molecules were formed with the substituents in trans arrangement... 

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