Self-assembly of tri-pyrazolate linked cages with di-palladium coordination motifs

By employing di-palladium complexes [(N^N)2Pd2(NO3(-))2](NO3(-))2 (where N^N = 2,2'-bipyridine, bpy; 4,4'-dimethylbipyridine, dmbpy; 1,10-phenanthroline, phen) as corners and tripyrazole functional ligands () as linkers, a series of highly-positively-charged tripyrazolate-bridged metallo-cages with different conformations and cavities such as [Pd6L2](6+) ( or , where L = L(1) or L(5)), [Pd10L(2)4](10+) (, and , where L = L(2) or L(4)) and [Pd12L4](12+) ( or , where L = L(3) or L4) have been synthesized through a di-metal coordination directed self-assembly with spontaneous deprotonation of the tripyrazole ligands in aqueous solution. These complexes have been fully characterized by (1)H and (13)C NMR, cold-spray ionization or electron spray ionization mass spectrometry (CSI-MS, ESI-MS) and elemental analysis. Complexes , , , and have also been determined by single-crystal X-ray diffraction structural analysis. In the case of complex , six PF6(-) anions were encapsulated within the cavity composed of adjacent di-Pd corners.