Optical resolution of trans-bicyclo[2.2.1]heptane-2,3-diamine: chiral recognition in the crystal of its complex with (2R,3R)-O,O′-dibenzoyltartaric acid

Author(s):  
Keiichiro Hatano ◽  
Tadahiro Takeda ◽  
Reiko Saito
2020 ◽  
Author(s):  
Haruka Kano ◽  
Hironobu Hayashi ◽  
Kyohei Matsuo ◽  
Michiya Fujiki ◽  
Hiroko Yamada ◽  
...  

Abstract Optically active fullerenes (C76, C82, C84), including C60 and C70 derivatives carrying organic substituents, possess various potent applications because of unique spectroscopic, catalytic, and chiral recognition properties. However, their inherent photoexcited chirality has not yet been elucidated because of a very poor quantum yield of fluorescence (FL). With this background in mind, we synthesized new chiral C70 derivatives, X70A, solely by reacting bis-borylated xanthene with C70 in a one-step double addition reaction with 20% yield, followed by a successful optical resolution using a recyclable chiral-HPLC technique. The isolated X70A enantiomers were confirmed by their mirror-image circular dichroism spectra in the range of 300 nm and 700 nm. The enantiomeric pair of X70A in toluene revealed clearly mirror-image circularly polarized luminescence (CPL) spectra with a high |glum| value of 7.0 × 10–3 at 690 nm associated with FL lifetime of 0.99 ns. The deep-red CPL of X70A should provide new photofunctionality as chiral nanocarbon materials.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haruka Kano ◽  
Hironobu Hayashi ◽  
Kyohei Matsuo ◽  
Michiya Fujiki ◽  
Hiroko Yamada ◽  
...  

AbstractOptically active fullerenes, including C60 and C70 derivatives carrying organic substituents, are used in a range of applications because of their unique spectroscopic, catalytic, and chiral recognition properties. However, their inherent photoexcited chirality is yet to be elucidated because of their very poor fluorescence quantum yield (Φf). We synthesised a new chiral C70 derivative, X70A, with 20% yield, by reacting bis-borylated xanthene with C70 in a one-step double addition reaction, followed by a successful optical resolution. The isolation of two separate X70A enantiomers was confirmed by mirror-image circular dichroism spectroscopy in the range of 300–750 nm. In toluene, the enantiomeric pair of X70A clearly revealed mirror-image circularly polarised luminescence (CPL) spectra with a high |glum| value of 7.0 ×  10−3 at 690 nm. The first fullerene-based deep-red CPL of X70A should provide a new guideline for the design of chiral nanocarbon materials.


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