Enhancement of circularly polarized luminescence (CPL) dissymmetry factor by a guest‒host interaction in chromophore encapsulated homochiral gyroidal MOFs Kazuya Nakashima 1 , Rie Suizu1,2 , Shuhei Morishita 3 , Noriaki Tsurumachi 3 , Masahiro Funahashi 3 , Hyuma Masu 4,5 , Ryuki Ozawa5,6, Kazuki Nakamura 5 and Kunio Awaga 1 1 Department of Chemistry and IRCCS, Nagoya University, Japan, 2 Japan Science and Technology Agency (JST), PRESTO, Japan, 3 Program in Advanced Materials Science, Kagawa University, Japan, 4 Center for Analytical Instrumentation, Chiba University, Japan, 5 Graduate School of Engineering, Chiba University, Japan, 6 Research Fellowship of Japan Society for the Promotion of Science for Young Scientists, Japan
Circularly polarized luminescence (CPL) is an optical phenomenon that can be provided by specific material with chiral structures and cause differential emission intensities of right and left circularly polarized light. In recent years, there has been growing attention on the development of CPL materials especially in the solid states due to the numerous potentials on applications such as optical data storage, displays, back-lights in 3D displays, and so on. Although there has been a great deal of research to develop higher-performance CPL materials, few materials have reached practical application. Therefore, we focused on gyroidal complexes including the [Ru(bpy) 3 ] 2+ cation, which is well-known as luminescent compounds exhibiting CPL, to enhance their CPL properties by guest-host interaction. In particular, the single gyroid lattice which has both chirality and huge cavities with high symmetry structure is expected to be a suitable host. This lattice also has been attracted for mathematically proven to have a property called "strong isotropy." 1 Recently, we found that homochiral metal-organic-frameworks (MOFs) [Ru(bpy) 3 ][M2(ox) 3 ] (M=Zn (2), Mn (3)) 2 with gyroidal structure exhibit the CPL with large dissymmetry factor. Following the procedure reported 2 , we have successfully synthesized the homochiral gyroidal MOFs that encapsulate the optically resolved luminescent molecule [Ru(bpy) 3 ]I 2 (1) as a template. The highest CPL dissymmetry factor we obtained was from 3 in the solid state and showed |g e |~ 10 -1 , which was significantly enhanced compared to |g e |~ 10 -2 for the parent complex 1 in the solid state, much more than |g e |~ 10 -4 for 1 in the solution state. Although their absorption and luminescence spectra showed similar shapes for each of 1, 2 and 3, the intensities were very different: those of 1 and 2 were almost same, while that of 3 was significantly lower. We took place the luminescence lifetime and quantum yield measurements of 1-3 and their results indicated the existence of guest-host interaction between luminescent molecule 1 and the gyroidal structure 3. Based on these data, we will discuss the CPL in 1~3, especially the enhancements of CPL dissymmetry factor on 3. References 1. T. Sunada Not. Am. Math. Soc. 55 , 208-215 (2008). 2. a) F. Pointillart, et al., Tetrahedron: Asymmetry 17, 1937 (2006). b) C. A. Kent, et al., J. Mater. Chem. A, 1, 14982 (2013).
F27
© The Author(s), 2023
Made with FlippingBook Learn more on our blog