Fl-Diketonates

A mixture of an acid anhydride and a ketone is saturated with boron trifluoride ibis is followed by treatment with aqueous sodium acetate. The quantity of boron trifluoride absorbed usually amounts to 100 mol per cent, (bas on total mob of ketone and anhydride). Catalytic amounts of the reagent do not give satis ctory results. This is iu line with the observation that the fl-diketone is produced in the reaction mixture as the boron difluoride complex, some of which have been isolated. A reasonable mechanism of the reaction postulates the conversion of the anhydride into a carbonium ion, such as (I) the ketone into an enol type of complex, such as (II) followed by condensation of (I) and (II) to yield the boron difluoride complex of the p-diketone (III) ... 

Table 10 Hydrogen-bond lengths, chemical shifts and vibrational mode of selected enol tautomers of fl-diketones.

The third section will contain direct reactions of stable chelates. This is a large and diffuse topic and many examples of reactions of this type are included in Chapter 7.4. In the current chapter, a more detailed discussion of the most important areas, namely complexes of fl-diketones and q-amino acids and their derivatives, will be offered. Also some important organic reactions of carbonyl compounds will be considered with regard to the nature of their chelated transition states and the effects these have on product formation. 

Furan annelation. The reagent reacts with the enolate of dimethyl malonate (2) to form furan 3 in good yield. A similar reaction of 1 with a fl-diketone (4) and NaOCHj in CH3OH is accompanied by deacylation to provide fiirans such as 5. 

M(/3-Diketonate)2 (Polydentate) Compounds Chemical and Physical Properties of fl-Diketonate and Ketoiminate Compounds with Polydentate Bases... 

The bond between the two carbonyl groups of the fl-diketone is cleaved by potassium methoxide present in the methanolic aqueous potassium hydroxide, and the cyclopropane ring is split open while the carbonyl group is converted to a carboxyl to give methyl 4-oxo-2-phenylpentanoate [69]. 

The vibrational assignments for a selection of fl-diketones are given in Table 10, which includes those (3-diketones for which complete structural and nmr data are available. 

Chauvin, A.S., Gumy, R, Matsubayashi, I., etal. (2006) Fluorinated fl-diketones for the extraction of lanthanide ions photophysical properties and hydration numbers of their Eu " complexes. European Journal of Inorganic... 

Influence of fl-diketone ligand on fluorescence of rare earth complex in LB film... 

Higher ketones (3-83), usually C24-C33 compounds, arise as products of oxidation of alkanes via secondary alcohols. Higher fl-diketones, mainly C33 and C33 compounds (3-84), also accompany higher ketones in smaller amounts. 

Coordination of a deprotonated tripodal tris-fl-diketone ligand syntones 385 to copper(ll) ions by... 

Figure 3.11 Observed deuterium isotope effects on C chemical shifts of fl-diketones as a function of the mole fraction. (Reproduced from Bordner et al. [21]. Copyright (1989), with permission of Wiley-VCH.)...

Luminescence of Lanthanide Ions in Coordination Compounds and Nanomaterials 4.3.1.1 Molecular fl-Diketonate Probes and Conjugates... 

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