Solid-State TICT-Emissive Cruciform: Aggregation-Enhanced Emission, Deep-Red to Near-Infrared Piezochromism and Imaging In Vivo

摘要

Near-infrared piezochromic materials presenting fluorescence responseswith clear color differences and good penetrability have important potentialapplications, but a few such organic compounds are developed. Twistedintramolecular charge transfer (TICT) emission is versatile in solutions,especially for preparing bio/chem-sensing materials due to the excellentsensitivity of the emission to alterations in the external environment. Byanalogy, the solid-state TICT-emissive chromophores are probably excellentcandidates for the environmentally responsive material. Herein, X-shapedπ architectures that exhibit solid-state TICT emission are developed, andtheir luminescent chromism and bioimaging properties are investigated.Initially, the cruciform fluorophore exhibits anomalous aggregationenhancedemission (AEE) and dual emission due to the existence of a TICTstate. Interestingly, TICT emission is observed even in the aggregated statebecause the spacious environment around the bulky triphenylamine allowsfor rotation. During the compression process, the TICT-based fluorophoredemonstrates deep-red to near-infrared piezochromic behavior with aremarkable redshift (162 nm) and high sensitivity (15.1 nm Gpa~（−1）). The bioimagingperformance of the TICT-emissive dye suggests its potential utilityas a fluorescent probe for biological applications.