Premium
Three‐Component Self‐Assembly of a Series of Triply Interlocked Pd 12 Coordination Prisms and Their Non‐Interlocked Pd 6 Analogues
Author(s) -
Bar Arun Kumar,
Raghothama Srinivasarao,
Moon Dohyun,
Mukherjee Partha Sarathi
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201102963
Subject(s) - ethylenediamine , chemistry , diamine , stereochemistry , crystallography , supramolecular chemistry , benzene , coordination complex , palladium , bipyridine , crystal structure , polymer chemistry , catalysis , metal , inorganic chemistry , organic chemistry
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 PdN/PdO 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.