Paracetamol Inclusion in Mechanically Interlocked Nanocages.

The solid-state synthesis and fast crystallization under kinetic control of poly-[n]-catenanes self-assembled of mechanically interlocked metal organic cages (MOCs) is virtually unexplored. This is in part, due to the lack of suitable crystals for single crystal X-ray diffraction (SC-XRD) analysis which limits their progress as advanced functional materials. Here we report the unprecedented inclusion of paracetamol in the cavities of amorphous materials constituted of M ₁₂ L ₈ , interlocked MOCs synthesized by mechanochemistry under kinetic control. Full structure determination of a low-crystallinity and low-resolution powders of the M ₁₂ L ₈ poly-[n]-catenane including paracetamol has been carried out combining XRD data and Density Functional Theory (DFT) calculations using a multi-step approach. Each M ₁₂ L ₈ cage contains six paracetamol guests which is confirmed by thermal analysis and NMR spectroscopy. The paracetamol loading has been also carried out by the instant synthesis method using a saturated paracetamol solution in which TPB and ZnI ₂ self-assemble immediately (i. e., 1-5 seconds) encapsulating ~7 paracetamol molecules in the M ₁₂ L ₈ nanocages under kinetic control also giving a good selectivity. Benzaldehyde has been included in the M ₁₂ L ₈ cages using amorphous M ₁₂ L ₈ polycatenanes showing that the icosahedral cages can serve as potential nanoreactors for instance to study Henry reactions in the solid-state.
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