Near-Infrared-I to III Absorption and Emission via Core Engineering of Open-Shelled Organic Mixed-Valence Systems.

A novel class of agents is developed based on the core engineering of open-shelled organic mixed-valence (MV) systems, which enable tunable absorption and emission across the near infrared (NIR)-I to III biowindow (700-1850 nm) by adjusting the number of central nitrogen oxidation sites and the length of the conjugated bridge. Organic mixed-valence (MV) systems are synthesized through a one-step partial chemical oxidation of starburst oligoarylamines, with varying nitrogen oxidation sites and conjugated bridge lengths, including tris(4-[diethylamino]phenyl)amine (T4EPA ), N,N,N',N'-tetrakis(4-[diisobutylamino]phenyl)-1,4-phenylenediamine (TPDA ), and N,N,N',N'-tetrakis(4-methoxyphenyl)benzidine (TMPB ). The absorption wavelength of the MV systems redshifted clearly as the number of central nitrogen oxidation sites increased or the conjugated bridge length is prolonged.