121st General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code MAT.P-361
Subject Amplified Circularly Polarized Phosphorescence from Co-Assemblies of Platinum(II) Complexes
Authors Gyurim Park, Youngmin You1,*
of Chemical Engineering and Materials Science, Ewha Womans University, Korea
1Division of Chemical Advanced Materials, Ewha Womans University, Korea
Abstract

Circularly polarized luminescence (CPL) is the differential emission of right- and left-handed circularly polarized lights. CPL has a variety of photonic utility, including 3D electroluminescence displays, optical storages, spintronic applications, enantioselective probes, security tags, lasers and the asymmetric photosynthesis. However, the most of CPL-active molecules are far from practical utility, because they suffer from small dissymmetric factors (|glum|) and low quantum yields for CPL. To address this challenge, we exploited the sergeants-and-soldiers principle. In our approach, an achiral monocyclometalated platinum(II) complex having 4,4-bisnonyl-2,2-bipyridine (denoted as PtN) and an enantiomeric pair of monocyclometalated platinum(II) complexes having the Masamune Box ligands (denoted as (R)- and (S)-PtBox) were synthesized and employed for the soldiers and sergeant, respectively. PtN co-assembled with (R)- or onto glass substrates. AFM and SEM images revealed that the enantioselective formation of the helical (S)-PtBox into homochiral helical wires upon drop-casted wires was dictated by the chirality of PtBox. The helical co-assemblies exhibited strong Cotton effects at the metal-to-ligand charge-transfer transition of PtN in the circular dichroism spectra, suggesting exciton coupling to be responsible for the chiroptical effect (gabs= +0.02 and 0.02 for the (R)-Ptbox/PtN co-assemblies and (S)-Ptbox/PtN co-assemblies, respectively, at 500 nm). Finally, CPL spectra with high dissymmetry factors (glum= 0.05 and +0.05 for (R)-Ptbox/PtN co-assemblies and (S)-Ptbox/PtN co-assemblies, respectively, at 570 nm) were observed. Such amplification in the chiroptical properties was ascribed to transfer of both chirality and energy from PtBox to PtN.

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