Self-assembly and host-guest interaction of metallomacrocycles using fluorescent dipyrazole linker with dimetallic clips

摘要

By employing diimine ligands coordinated dimetallic clips ([(bpy) _2Pd_2(NO_3)_2](NO_3) _2 or [(phen)_2Pd_2(NO_3) _2](NO_3)_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 ([M_4L_2]~(4+) or [M _8L_4]~(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, ~1H and ~(13)C NMR, electrospray ionization mass spectrometry, and single crystal X-ray diffraction analysis for compound 1 4PF_6 (1 = {[(bpy)Pd]_4L~1_2}~(4+)), 3 4PF_6 ·8CH_3CN· H_2O (3 = {[(bpy)Pd]_4L~2_2} ~(4+)), and 7 4PF_6·6H_2O (7 = {[(bpy)Pd]_4L~5_2}~(4+)). The 1:1 host-guest complexation for anthracene-based dipyrazolate-bridged macrocycles with aromatic guests was investigated via UV-vis and fluorescent titration.