Three‐Component Self‐Assembly of a Series of Triply Interlocked Pd12 Coordination Prisms and Their Non‐Interlocked Pd6 Analogues

Template-assisted formation of multicomponent Pd (6) coordination prisms and formation of their self-templated triply interlocked Pd (12) analogues in the absence of an external template have been established in a single step through Pd-N/Pd-O coordination. Treatment of cis-Pd (en) (NO (3) ) (2) with K (3) tma and linear pillar 4, 4'-bpy (en=ethylenediamine, H (3) tma=benzene-1, 3, 5-tricarboxylic acid, 4, 4'-bpy=4, 4'-bipyridine) gave intercalated coordination cage Pd (en) (6) (bpy) (3) (tma) (2) (2) NO (3) (12) (1) exclusively, whereas the same reaction in the presence of H (3) tma as an aromatic guest gave a H (3) tma-encapsulating non-interlocked discrete Pd (6) molecular prism Pd (en) (6) (bpy) (3) (tma) (2) (H (3) tma) (2) NO (3) (6) (2). Though the same reaction using cis-Pd (NO (3) ) (2) (pn) (pn=propane-1, 2-diamine) instead of cis-Pd (en) (NO (3) ) (2) gave triply interlocked coordination cage Pd (pn) (6) (bpy) (3) (tma) (2) (2) NO (3) (12) (3) along with non-interlocked Pd (6) analogue Pd (pn) (6) (bpy) (3) (tma) (2) (NO (3) ) (6) (3'), and the presence of H (3) tma as a guest gave H (3) tma-encapsulating molecular prism Pd (pn) (6) (bpy) (3) (tma) (2) (H (3) tma) (2) NO (3) (6) (4) exclusively. In solution, the amount of 3' decreases as the temperature is decreased, and in the solid state 3 is the sole product. Notably, an analogous reaction using the relatively short pillar pz (pz=pyrazine) instead of 4, 4'-bpy gave triply interlocked coordination cage Pd (pn) (6) (pz) (3) (tma) (2) (2) NO (3) (12) (5) as the single product. Interestingly, the same reaction using slightly more bulky cis-Pd (NO (3) ) (2) (tmen) (tmen=N, N, N', N'-tetramethylethylene diamine) instead of cis-Pd (NO (3) ) (2) (pn) gave non-interlocked Pd (tmen) (6) (pz) (3) (tma) (2) NO (3) (6) (6) exclusively. Complexes 1, 3, and 5 represent the first examples of template-free triply interlocked molecular prisms obtained through multicomponent self-assembly. Formation of the complexes was supported by IR and multinuclear NMR ( (1) H and (13) C) spectroscopy. Formation of guest-encapsulating complexes (2 and 4) was confirmed by 2D DOSY and ROESY NMR spectroscopic analyses, whereas for complexes 1, 3, 5, and 6 single-crystal X-ray diffraction techniques unambiguously confirmed their formation. The gross geometries of H (3) tma-encapsulating complexes 2 and 4 were obtained by universal force field (UFF) simulations.