Eufod

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Eufod
Other names	Eu(fod)3, Eu(dpm)3
Identifiers
CAS number	[17631-68-4]
Properties
Molecular formula	C30H30EuF21O6
Molar mass	1037.49 g/mol
Appearance	Yellow powder
Melting point	203-207 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Eu(fod) is the chemical compound with the formula Eu(OCC(CH₃)₃CHCOCF₂CF₂CF₃)₃, also called Eu(fod)₃. This coordination compound is used primarily as a shift reagent in NMR spectroscopy. It is the premier member of the lanthanide shift reagents and was popular in the 1970s and 1980s> The availability of higher magnetic field spectrometers have made this application obsolete because they can better resolve signals.

Contents 1 Structure and reactivity 2 Uses 2.1 As an NMR shift reagent 2.2 As a Lewis acid 3 References

[edit] Structure and reactivity

Eu(fod)₃ consists of three bidentate acetylacetonato ligands bound to a Eu(III) center. Eu(III) has an elecron configuration f6, which means that it has six electrons in the f-orbitals. These electrons are unpaired, which implies that each molecule is highly paramagnetic. The complex is a Lewis acid, being capable of expanding its coordination number of six to eight. The complex displays a particular affinity for a "hard" Lewis bases, such as ether and amines. It is soluble in nonpolar solvents.

[edit] Uses

[edit] As an NMR shift reagent

The original application of Eu(fod)₃ was for analyzing diastereomeric compounds in NMR spectroscopy. The paramagnetic compound induces shifts in the protons near the Lewis basic site(s) of the molecule, which helps to resolve closely-spaced signals. Only small amounts of shift reagents are used because the paramagnetism of the reagent shortens the spin-lattice relaxation times of the nuclei, which causes uncertainty broadening and loss of resolution.

[edit] As a Lewis acid

Eu(fod)₃ has been examined as a Lewis acid in stereoselective catalysis in organic synthesis including Diels-Alder and aldol additions. For example, Eu(fod)₃ catalyzes the cyclocondensations of substituted dienes with aromatic and aliphatic aldehydes to yield dihydropyrans, with high selectivity for the endo product.^[1]

[edit] References

1. ^ Wenzel, T.J.; Ciak, J.M.; "Europium, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedianato)" in Encyclopedia of Reagents for Organic Synthesis, 2004. John Wiley & Sons, Ltd. doi:10.1002/047084289X.rn00449