Self-Assembly and Host-Guest Interaction of Metallomacrocycles Using Fluorescent Dipyrazole Linker with Dimetallic Clips

By employing diimine ligands coordinated dimetallic clips ([(bpy)(2)Pd-2(NO3)(2)](NO3)(2) or [(phen)(2)Pd-2(NO3)(2)KNO3)(2), where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) as the corner and anthracene-, naphthalene-, and benzene-based dipyrazolate dianions as the linker, a series of positively charged metallomacrocycles ([M4L2](4+) or [M8L4](8+)) have been synthesized through a directed self-assembly method in aqueous solution. Every macrocycle has a cavity to bind solvent molecules or anions. The structures were characterized by elemental analysis, H-1 and C-13 NMR, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis for compound 1.4PF6(-) (1 = {[(bpy)Pd](4)L-2(1)}(4+)), 3 center dot 4PF(6)(-)center dot 8CH(3)CN center dot H2O (3 = {[(bpy)Pd](4)L-2(2)}(4+)), and 7.4PF(6)(-)center dot 6H(2)O (7 = {[(bpy)Pd](4)L-2(5)](4+)). The 1:1 host guest complexation for anthracene-based dipyrazolate-bridged macrocycles with aromatic guests was investigated via UV-vis and fluorescent titration.