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Lanthanide Polyoxocationic Complexes: Experimental and Theoretical Stability Studies and Lewis Acid Catalysis
Author(s) -
El Moll Hani,
Nohra Brigitte,
Mialane Pierre,
Marrot Jérôme,
Dupré Nathalie,
Riflade Benoît,
Malacria Max,
Thorimbert Serge,
Hasenknopf Bernold,
Lacôte Emmanuel,
Aparicio Pablo A.,
López Xavier,
Poblet Josep M.,
Dolbecq Anne
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201101754
Subject(s) - polyoxometalate , catalysis , lanthanide , chemistry , lewis acids and bases , molybdate , inorganic chemistry , chloride , keggin structure , rare earth , ion , crystallography , medicinal chemistry , organic chemistry , mineralogy
The [ε‐PMo V 8 Mo VI 4 O 36 (OH) 4 {Ln III (H 2 O)} 4 ] 5+ (Ln=La, Ce, Nd, Sm) polyoxocations, called εLn 4 , have been synthesized at room temperature as chloride salts soluble in water, MeOH, EtOH, and DMF. Rare‐earth metals can be exchanged, and 31 P NMR spectroscopic studies have allowed a comparison of the affinity of the reduced {ε‐PMo 12 } core, thus showing that the La III ions have the highest affinity and that rare earths heavier than Eu III do not react with the ε‐Keggin polyoxometalate. DFT calculations provide a deeper insight into the geometries of the systems studied, thereby giving more accurate information on those compounds that suffer from disorder in crystalline form. It has also been confirmed by the hypothetical La→Gd substitution reaction energy that Ln ions beyond Eu cannot compete with La in coordinating the surface of the ε‐Keggin molybdate. Two of these clusters (Ln=La, Ce) have been tested to evidence that such systems are representative of a new efficient Lewis acid catalyst family. This is the first time that the catalytic activity of polyoxocations has been evaluated.