Comparison of Vinyldimethylaniline and Indolizine Donor Groups on Si‐Substituted Xanthene Core Shortwave Infrared Fluorophores

• DOI: 10.1002/cptc.202400023
• Publication Date: 2024-03-27T03:19:25Z
• Authors: Ravinder Kaur; Nicholas A. Kruse; Cameron Smith; Nathan I. Hammer; Jared H. Delcamp
• Keywords: Xanthene; Indolizine; Shortwave

Abstract Small organic molecules absorbing and emitting in the shortwave infrared (SWIR, 1000–2000 nm) region are desirable for biological imaging applications due to low auto‐fluorescence, reduce photon scattering, good tissue penetration depth of photons which allows vivo with high resolution sensitivity. Si‐substituted xanthene‐based fluorophores indolizine donors have demonstrated some longest wavelengths absorption emission from dyes. This work seeks compare an heterocyclic nitrogen dimethyl aniline on otherwise identical xanthene via optical spectroscopy, computational chemistry electrochemistry. Three compared including donor, a ubiquitous vinyl group that keeps number π‐bonds consistent indolizine. Significantly higher quantum yields molar absorptivity observed these studies dimethylamine‐based donor relative simple at similar (~1312 nm emission). Substantially longer obtainable by appending aniline‐based groups (~1700 indicating can be accessed while stronger emitters anilines place