Eufod

Chembox new
Name = Eufod
ImageFile = Eufod.png OtherNames = Eu(fod)₃, Eu(dpm)₃
Section1 = Chembox Identifiers
CASNo = 17631-68-4
Section2 = Chembox Properties
Formula = C₃₀H₃₀EuF₂₁O₆
MolarMass = 1037.49 g/mol
Appearance = Yellow powder
Density =
Solubility =
MeltingPt = 203-207 °C
BoilingPt =

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.

tructure 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.

Uses

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.

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. [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]

References