Recent Developments of Lewis Acids Catalysis: Lanthanide Catalysts with Long Perfluoro-Chain in Organic Chemistry

Abstract

Recently, the concept of fluorous bi-phasic catalysis (FBC) was introduced as an environmentally benign recyclable process. Numerous nine and long-enough (e.g. perfluorooctyl, C 8 F 17 ) fluorous ponytails can be employed for fluorous phase immobilization of lanthanide catalysts and to catalyze the Diels-Alder and Friedel-Crafts reactions more efficiently. Meanwhile, Bis(perfluoroalkylsulfonyl)amides of lanthanum, ytterbium, yttrium, and scandium have been described as strong Lewis acids, more powerful catalysts for Diels-Alder acylation, esterification, and Baeyer-Villiger reactions. The key to success is that lanthanide complexes are extremely efficient Lewis acid catalysts by virtue of the highly electron-withdrawing and solubilizing effect of tris(perfluoroalkylsulfonyl)methide and bis(perfluoroalkylsulfonyl)amide without hydrocarbon spacers. On the other hand, it has been reported that a new rare earth perfluorocarboxylate catalyst, the rare earth perfluorooctanoate, showed efficient catalytic activity in the Mannich reaction and the reaction of indole with carbonyl compounds due to the unique surfactivity of the long perfluoro-chain. These catalysts can be prepared, stored and recoveredeasily. In this paper, we will review the application of long perfluoro-chain lanthanide catalysts in a series of organic reactions.

Group 4 Lanthanide and Actinide Organometallic Inclusion Complexes

“…Since the macrocyclic ligation has an overall charge of 3–, we expected certain lanthanide metals to form complexes with neutral ligands in the apical positions. These positions, as such, would be expected to be active for Lewis acid catalyzed reactions . At first we attempted the reaction with the Sm precursor Cp* 2 Sm(μ-Cl) 2 MgCl(THF) 2 with an excess of HBCat in toluene at room temperature to produce (η 2 -catechol-μ-catecholborate) 3 Sm(C 4 H 8 O) 3 ( 3 ), with the concomitant formation of MeBCat.…”

“…However, crystals of complex (η 2 -catechol-μ-catecholborate) 3 Nd(C 4 H 8 O) 3 ( 4 ) (Figure ), a macrocyclic complex isostructural with the Sm complex bearing a Nd at the metallic center, were obtained by the reaction of NdCl 3 with an excess of HBCat in refluxing toluene (with the formation of the byproduct ClBCat), followed by crystallization from a THF/hexane mixture. Complex 4 crystallizes in the monoclinic space group P 2 1 / n , and the neodymium complex 4 has slightly longer metal–macrocycle and metal–ligand bonds relative to the Sm complex 3 , attributed to the smaller ionic radii of the Sm center . Structural parameters comparing the most important features in complexes 2 – 6 are given in Tables and ; and a comparison of inclusion cavity sizes for complexes 2 – 6 is presented in Table .…”

Perylenetetracarboxylic anhydride as a precursor of fluorescent carbon nanoonion rings

“…In the literature there several examples showing that rare earth metal ions can act as Lewis acid esterification catalysts and the same function was expected here. 15,16 The selection of Eu(OAc) 3 was also based on the possibility to detect the presence of Eu in the sample by observing the characteristic photoluminescence of this lanthanide. [17][18][19] In comparison the use of ZnCl2 as Lewis acid to promote PEG esterification renders under the same conditions crude mixtures considerably more black, but where also C-Nor were observed.…”

Reusable and Efficient Polystryrene-supported Acidic Ionic Liquid Catalyst for Mononitration of Aromatic Compounds

“…Traditionally, they are performed with mixture of nitric and sulfuric acids, which is not environmental friendly and often provides poor selectivity. Various clean nitration approaches [1][2][3] have therefore been explored in order to avoid these insufficient. Since the end of last century, with more and more recognition of room temperature ionic liquids (TSILs), a growing interests have also been witnessed in ionic liquids as solvents or catalysts for aromatic nitration.…”