Diradicaloids

π-Conjugated molecules with even number of p-electrons usually have a closed-shell ground state. However, recent studies have demonstrated that a certain type of molecules could show open-shell singlet ground state and display diradical-like (diradicaloid) behavior. They are a new family of p-conjugated molecules with intermediate p-bonding, which are rarely exploited mainly due to their intrinsic chemical reactivity. Their electronic structure can be understood in terms of the “diradical character” and “aromaticity” concepts. They display unique optical, electronic and magnetic properties, dramatically different from traditional closed-shell p-conjugated molecules. They could become next-generation molecular materials for electronics, photonics, spintronics, magnets and quantum information processing. This is an emerging area in organic chemistry and materials science and has been largely developed in the past decade.

This book provides a comprehensive review on the chemistry, physics, and material applications of open-shell singlet diradicaloids. Particularly, it elaborates the fundamental structure–diradical character–electronic property relationships both theoretically and experimentally. The book has been written by leading scientists in the field from Japan, Germany, Spain, Italy, China, and Singapore.