| Abstract
| - The preparation of palladated methanofullerene NCN ligands was studied. These complexes were applied as catalyst precursors in the double Michael reaction and aldol condensation. The retention of palladium complex 15 was determined using a nanofiltration membrane.
- Synthetic routes have been developed for the attachment of palladium(II) bis(amino)aryl(NCN or C6H2{CH2NMe2}2-2,6)- complexes to C60. Using diazo and Bingel addition reactions, various methanofullerene NCN−SiMe3 compounds (C60−L−NCN−SiMe3, L = C(Me),C(CO2Et)CO2CH2, and C(Me)C6H4C⋮C) have been prepared and characterized. Electrophilic palladation of these ligands was achieved with Pd(OAc)2, leading to the correspondingC60−L−NCN·PdCl complexes. These were converted into active Lewis acid catalysts for thealdol condensation and the Michael reaction. Catalytic tests show that the activity of cationicmethanofullerene NCN−palladium complexes in the aldol reaction between benzaldehydeand methyl isocyanoacetate is comparable to the parent unsupported NCN palladiumcomplex. However, in the Michael reaction of methyl vinyl ketone and ethyl cyanoacetate,the fullerene catalysts are not only significantly slower but also undergo a deactivation/decomposition process during the reaction. Preliminary retention measurements using ananofiltration membrane have shown 72% retention of the palladium complex C60−C(Me)−(NCN)PdCl.
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