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

• DOI: 10.1002/adhm.202300484
• Publication Date: 2023-04-10T13:55:46Z
• Authors: Qiuyan Song; Manman Xu; Baoli Zhang; Mingxu He; Xindong Guo; Jun Nie; Yue Xing; Xiubing Liang; Yincheng Chang
• Keywords: Engineering; Nitrogen; Oxidation-Reduction

A novel class of agents is developed based on the core engineering open-shelled organic mixed-valence (MV) systems, which enable tunable absorption and emission across near infrared (NIR)-I to III biowindow (700-1850 nm) by adjusting number central nitrogen oxidation sites length conjugated bridge. Organic systems are synthesized through a one-step partial chemical starburst oligoarylamines, with varying bridge lengths, including tris(4-[diethylamino]phenyl)aminen+ (T4EPAn+ ), N,N,N',N'-tetrakis(4-[diisobutylamino]phenyl)-1,4-phenylenediaminen+ (TPDAn+ N,N,N',N'-tetrakis(4-methoxyphenyl)benzidinen+ (TMPBn+ ). The wavelength MV redshifted clearly as increased or prolonged. T4EPAn+ one site exhibits fluorescence in range 900-1400 nm, while TPDAn+ two demonstrate strong heat generation capabilities. Additionally, peak TMPBn+ biphenyl reaches up 1610 nm. Especially, these highly stable for biological applications due their high steric hindrance hyperconjugation effect. These characteristics make promising candidates constructing NIR-I/II/III emitters photothermal agents, representing significant advance toward developing next NIR-I agents.