Face-Directed Tetrahedral Organic Cage Anchored Palladium Nanoparticles for Selective Homocoupling Reactions

Numerous metalla-supramolecular architectures have been designed using coordination-driven self-assembly, while the number of analogous organic architectures is still very limited. In this regard, mainly di-, tri- and a few tetra-aldehydes have been exploited as precursors in combination with appropriate di-/tri-amines to obtain the desired structures with limited complexities. We report here facile synthesis of two face-directed tetrahedral organic cages (TC-R and TC-S) that were formed by [4+12] imine condensation of a new hexa-aldehyde precursor with two enantiomers of 1,2-diaminocyclohexane separately (CA-R and CA-S). The covalent imine cages are very large with an intrinsic porous cavity of similar to 1250 angstrom(3) and the faces of the cages consist of aromatic aldehyde units whereas each corner is occupied by three semi-flexible diamine moieties. Palladium (PdNPs) nanoparticles (3.5 +/- 0.3 nm) were synthesized employing the cage TC-R as a solid support via double-solvent approach. Furthermore, the cage hosted PdNPs [Pd(0)@TC-R-A] exhibited efficient catalytic activity for selective homocoupling of aryl- and hetero-aryl halides with high thermal stability and reusability.

Automated summary

This study presents the facile synthesis of two face-directed tetrahedral organic cages by condensation reaction. These cages are large with intrinsic porous cavities and exhibit high thermal stability. The synthesized cages can be used as solid supports for the synthesis of palladium nanoparticles, which show efficient catalytic activity for selective homocoupling reactions.