Acetylacetonate anion , transition metal

Acetylacetonate anion (acac), transition metal peroxides, 1086, 1089, 1090, 1092, 1095, 1100... 

In this reaction an anionic leaving group is replaced by a neutral donor molecule. Consequently, if relative EPD strengths of both neutral and anionic EPD units are known, it should be possible to make at least qualitative predictions about the ionizability of substrates A—Bj, A—Bg,. .. in various EPD solvents. Approximate values of relative EPD strength of halide, pseudohalide, and neutral EPD units have been determined using vanadyl(IV)acetylacetonate, VO(acac)2, as reference EPA (46) and are listed in Table VII. These values have proved useful for the interpretation of numerous reactions involving complex formation between transition metal ions and halide or pseudohalide ions... 

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.)... 

The interpretation of the experimental a constants for the fluoroalkyl and nitroxide radicals is complicated because the stereochemistry at the radical center is not well defined. This complication does not exist for radicals derived from aromatic compounds. Consequently, several research groups have investigated aromatic radicals to characterize the factors governing spin delocalization to /3-fluorine atoms. One aspect of this work concerns the epr spectra of nitrobenzene anion radicals. Another concerns the contact chemical shifts of paramagnetic transition metal complexes. The latter approach was initiated by Eaton, Josey, and Sheppard who examined stable bis(phenylaminotroponiminato)-nickel(II) complexes (55a). More recently, we have examined the contact chemical shifts in the nmr spectra of nickel acetylacetonate complexes of aniline derivatives (556). 

Verification of the methodology was achieved by using the echelle spectrometer system as an element selective detector for both anion exchange and reverse phase HPLC. The anion exchange work involved the separation and detection of the ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) complexes of Ca, Cu, and Mg, duplicating the work of Fraley et al. [51]. The reverse phase HPLC work consisted of the separation of acetylacetonate (AcAc) complexes of a number of transition metals employing a C-18 column and a 50 50 methanol water mobile phase. 

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