[M 8 L 4 ] 8+ -Type Squares Self-Assembled by Dipalladium Corners and Bridging Aromatic Dipyrazole Ligands for Iodine Capture.

Square-like metallamacrocyclic palladium(II) complexes [ M 8 L 4 ] 8+ ( 1-7 ) were synthesized by reacting aromatic dipyrazole ligands (H 2 L 1 -H 2 L 3 with pyromellitic arylimide-, 1,4,5,8-naphthalenetetracarboxylic arylimide-, and anthracene-based aromatic groups, respectively) with dipalladium corners ([(bpy) 2 Pd 2 (NO 3 ) 2 ](NO 3 ) 2 , [(dmbpy) 2 Pd 2 (NO 3 ) 2 ](NO 3 ) 2 , or [(phen) 2 Pd 2 (NO 3 ) 2 ](NO 3 ) 2 , where bpy = 2,2'-bipyridine, dmbpy = 4,4'-dimethyl-2,2'-bipyridine, and phen = 1,10-phenanthroline) in aqueous solutions via metal-directed self-assembly. Metallamacrocycles 1-7 were fully characterized by 1 H and 13 C nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry, and the square structure of 7· 8NO 3 - was further confirmed via single crystal X-ray diffraction. These square-like metallamacrocycles exhibit effective performance for iodine adsorption.