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  • Author: Eric Monflier x
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Abstract

The synthesis of water-soluble rhodium(I) salicylaldiminato and salicylhydrazonic complexes has been achieved employing two preparative routes. Schiff base condensation between 6A-deoxy-6A-amino-β-CD or 6A-deoxy-6A-hydrazino-β-CD and 5-sodiosulfonato-2-hydroxybenzaldehyde (sulfonated salicylaldehyde) (1) or 5-sodiosulfonato-3-tert-butyl-2-hydroxybenzaldehyde (sulfonated tBu-salicylaldehyde) (2) led to the formation of the corresponding imine or hydrazone ligands (3, 4, 5 and 6). Reaction of [Rh(COD)2 +BF4 ] with these new ligands in an alkaline solution formed the corresponding rhodium complexes quantitatively. These rhodium(I) complexes could also be prepared in one-pot by mixing, in stoichiometric proportions, the modified β-CDs with the sulfonated salicylaldehyde and with the rhodium precursor in an alkaline solution at room temperature. These rhodium complexes were applied as catalysts in the aqueous biphasic hydroformylation of 1-decene as a model reaction.

Abstract

Melamine based polymer (MT) was prepared and then reacted with a mixture of glucose (Glu) and β-cyclodextrin (CD) under hydrothermal conditions to afford, MT/Glu-CD. Then, the adsorption of Pd salt was realized on MT/Glu-CD. The resulting compound was subsequently carbonized to furnish Pd/MT/C that exhibited high catalytic activity for the hydrogenation of nitroarenes in aqueous media. To elucidate the roles of CD, Glu, the molar ratio of Glu:CD and the carbonization in the catalytic activity, several control catalysts have been prepared and their performances for a model hydrogenation reaction were compared with that of Pd/MT/C. The results confirmed the importance of the carbonization as well as the presence of CD for achieving high catalytic activity. Moreover, it was found that the molar ratio of Glu:CD could affect the catalytic activity of the final catalyst and the optimum molar ratio of Glu:CD was 30:70. The recycling test as well as measurement of Pd leaching demonstrated high recyclability and low Pd leaching of Pd/MT/C.

In this article, a brief review of the recent functionalizations of the cage-like water-soluble phosphine 1,3,5-triaza-7-phosphaadamantane (PTA), involving N-quaternization (lower rim) and introduction of a side arm in C-6 position (upper rim) will be presented, highlighting selected examples in their use as ligands for ruthenium(II), iridium(I), and rhodium(I) moieties together with applications of the related complexes in homogeneous catalysis.

An Introduction