Dual-Emissive Rectangular Supramolecular Pt(II)- p -Biphenyl with 4,4'-Bipyridine Derivative Metallacycles: Stepwise Synthesis and Photophysical Properties.

Mixed-ligand tetranuclear supramolecular coordination complexes (SCCs) of Pt(II)- p -biphenyl and bridging ligands derivatives of 4,4'-bypiridine ( 8 )-( 10 ), were synthesized and characterized. The SCCs were synthesized stepwise, starting from the Pt- p -biphenyl -Pt core. The crystal structure of complex {[Pt(2,2'-bpy)] 4 ( μ -bph) 2 ( μ -(4,4'-bpy) 2 }{PF 6 } 4 (2,2'-bpy = 2,2'-bipyridine, bph = p -biphenyl and 4,4'-bpy = 4,4' bipyridine), was determined using single-crystal diffraction methods. The emission profile of the tetranuclear complexes ( 8 )-( 10 ) was influenced by the length of the bridging ligands and was found to depend on solvent polarity. Dual-emission patterns in methanol-water mixtures were observed only in the cases of complexes ( 9 ) and ( 10 ), attributed to aggregation-induced emission phenomena.