Exploring Stable Yet Unusual π-Electron Materials
by Making Use of Phosphorus and Sulfur
The π-conjugated systems are indispensable building blocks in organic chemistry when we aim to attain optical and/or electronic functions with organic compounds. The molecular design of π-conjugated systems with unusual electronic structure and thus optical and/or electronic properties are of increasing importance for both progress of fundamental molecular science and development of next-generation optoelectronic materials. To this end, incorporation of main-group elements has been recognized as the one of the promising approaches toward the molecular design of π-conjugated systems with unusual electronic structure and thus optical and/or electronic properties. However, this approach often poses a challenge of compromise between unusual electronic structure and chemical stability of the resulting π-systems.
To tackle this issue, our group have so far focused on the latent characteristics of phosphorus and sulfur, the 3rd row p-block elements that forms rather strong bonds with carbon, and developed a number of novel p-electron systems with optical and/or electronic functions. These studies not only led to the generation of several outstanding functional materials including fluorescent probes with exceptional photostability,1 NIR-emissive yet stable fluorophores,2 two-electron-absorbing dyes,3 and solution-processable semiconductors,4 but also provided various new concepts in the rational molecular design of functional p-electron systems. In this presentation, I will describe the overview of our work and some of recent studies on the sulfur-containing heterocycles towards 1) the renaissance of the chemistry of nonbenzenoid hydrocarbons,5 and 2) the unconventional approach for solubilizing and molecular alignment of π-conjugated systems.4