著者

張本 尚 石垣 侑祐

出版者

公益社団法人 有機合成化学協会

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.81, no.10, pp.963-977, 2023-10-01 (Released:2023-10-05)

参考文献数

40

---

In recent years, near-infrared (NIR) dyes, exhibiting absorption in the NIR region (750-2500 nm), has been applied to various optical applications such as security marking, photovoltaic cells and chemotherapy of deep tissues in vivo. Electrochromic systems capable of switching NIR absorption are attractive from the viewpoint of applications for material and life science, and thus several examples have been reported to date. The development of organic-based materials is needed to reduce the environmental impact and improve biocompatibility. However, since the redox states of organic NIR dyes are generally unstable, the switching of NIR absorption based on quantitative redox interconversion is still a challenging issue regarding reversibility and durability during their interconversion. To construct organic electrochromic systems capable of ON/OFF switching of NIR-absorbing properties, we have focused on the non-aromatic π-conjugated para-quinodimethane (p-QD) skeleton. Herein, we have shown several studies on the synthesis and functional control of NIR electrochromic molecules based on redox-active p-QD scaffolds. We have elucidated the spectroscopic and electrochemical properties of various arylated quinodimethane derivatives and demonstrated that p-QD building blocks can be versatile components for the development of NIR switchable organic electrochromic systems.

著者

石垣 侑祐

出版者

公益社団法人 有機合成化学協会

雑誌

有機合成化学協会誌 (ISSN:00379980)

巻号頁・発行日

vol.79, no.4, pp.290-299, 2021-04-01 (Released:2021-04-07)

参考文献数

35

---

The carbon-carbon covalent bond is one of the most basic concept in organic chemistry. Bond length, bond angle, and torsion angle among carbon atoms are nearly constant on the basis of the bond order and hybrid orbitals. On the other hand, highly strained hydrocarbons such as sterically-congested and/or curved polycyclic aromatic hydrocarbons have attracted much attention with regard to their characteristic features. Regarding the C-C single bond, whose standard length is 1.54 Å, several attempts have been made to elongate the C-C single bond to gain new insight into the chemical bond and understand what happens at the limits of a bond. In contrast to the standard C=C double bond with planarity, the overcrowded ethylenes (OCEs) with bulky substituents can adopt anti-folded, syn-folded and/or twisted forms due to the steric hindrance around the central C=C double bond, and thus many OCEs exhibit photo- and thermochromic behavior upon exposure to external stimuli. Herein, we focus on redox-active hydrocarbons with two dibenzocycloheptatriene units, where unprecedented flexible C-C bonds based on extremely elongated C-C single bonds and control of HOMO levels were demonstrated. Thus, these highly strained hydrocarbons could be promising candidates for the development of functional materials.