Tuning the NIR Absorption Properties of 1,3,4,6,9b-Pentaazaphenalene Derivatives Through the Spatially Separated Frontier Molecular Orbitals

摘要

Strategical modulation of energy levels of molecular electronic orbitals and resulting near-infrared (NIR) absorption properties of 2,5,7,9-tetrasubstituted 1,3,4,6,9b-pentaazaphenalene (5AP) derivatives are reported. Recent reports on NIR-absorbing materials mainly rely on donor-acceptor electronic interactions or macrocyclic pi-conjugated systems. We achieved the narrow HOMO-LUMO gap based on spatially separated frontier molecular orbitals (FMOs) of 5APs. The FMOs of 5APs enabled us to selectively tune either their HOMO or LUMO by choosing the position of the substituent.