121st General Meeting of the KCS

Type Poster Presentation
Area Organic Chemistry
Room No. Event Hall
Time 4월 19일 (목요일) 11:00~12:30
Code ORGN.P-551
Subject Synthesis and Fine-Tuning of Redox Properties of Planar, Antiaromatic Naphthorosarins
Authors Dikhi Firmansyah, Jinhee Bae1, Hye Ryung Byon1,*, Chang Hee Lee*
Department of Chemistry, Kangwon National University, Korea
1Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
Abstract Naphthorosarin possesses Huckel’s 24π antiaromatic character and is known to form a stable 25pi-system upon treatment with strong acid such as TFA and HCl. In spite of this interesting PCET (Proton couled electron transfer) activity, no other naphthorosarin derivatives especially bearing substituents on the periphery were reported due to limited accessibility to the key building block, naphthobipyrroles. With these regards, we developed new synthetic methods of naphthorosarins bearing substituents on the peripheral naphthalene moieties. The synthesized compounds were fully characterized by 1H NMR, HRMS and single crystal X-ray diffraction analysis. The photophysical and electronic effects of the peripheral substituents were also studied for better insight into the electron transfer reactions involved with PCET. The newly synthesized naphthorosarin derivatives exhibited a negligible changes in absorption spectra but 1H NMR spectra revealed slightly decreased antiaromaticity upon electron withdrawing fluoride substitution on the peripheral naphthalene moieties. The free base has more negative reduction potential (ΔE ≈0.1 V) but the oxidation potential remained intact. The naphthorosarin bearing meso-(2,6-dichloro)phenyl groups exhibited slower rate in single electron reduction upon treatment with acid. The findings presented here clearly demonstrates that the fine-tuning of the redox properties is possible by introduction of peripheral substituents on the antiaromatic naphthorosarin.
E-mail chhlee@kangwon.ac.kr