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.