Outline

The carbon-carbon (C-C) covalent bond is one of the most basic concept in organic chemistry. Bond length and bond angle among carbon atoms are nearly constant on the basis of the bond order and hybrid orbitals. On the other hand, highly strained molecules with unique geometric parameters have attracted much attention with the expectation of the appearance of their characteristic features.

I have focused on redox-active strained molecules with extremely elongated C-C single bond or non-planar C=C double bond. Actually, we discovered unprecedented flexibility of an extremely elongated C-C single bond with a bond length beyond 1.8 Å based on our original molecular design concept. In addition, we have demonstrated the unique stimuli-responsive behaviors of redox-active overcrowded ethylenes with non-planar geometries. Now, we are seeking the ultimate C-C covalent bonds and unprecedented phenomena that could become the novel standard in chemistry.