Trisaminocyclopropenium Cations as Small-Molecule Organic Fluorophores: Design Guidelines and Bioimaging Applications

Abstract

The discovery of fluorescence two centuries ago ushered in, what is today, an illuminating field of science rooted in the rational design of photochromic molecules for task-specific bio-, material-, and medical-driven applications. Today, this includes applications in bioimaging and diagnosis, photodynamic therapy regimes, in addition to photovoltaic devices and solar cells, among a vast multitude of other usages. In furthering this indispensable area of daily life and modern-day scientific research, we report herein the synthesis of a class of trisaminocyclopropenium fluorophores along with a systematic investigation of their unique molecular and electronic dependent photophysical properties. Among these fluorophores, tris[N(naphthalen-2-ylmethyl)phenylamino] cyclopropenium chloride (TNTPC) displayed a strong photophysical profile including a 0.92 quantum yield ascribed to intramolecular charge transfer and intramolecular through-space conjugation. Moreover, this cyclopropenium-based fluorophore functions as a competent imaging agent for DNA visualization and nuclear counterstaining in cell culture. To facilitate the broader use of these compounds, design principles supported by density functional theory calculations for engineering analogs of this class of fluorophores are offered. Collectively, this study adds to the burgeoning interest in cyclopropenium compounds and their unique properties as fluorophores with uses in bioimaging applications.

Promoting halogen-bonding catalyzed living radical polymerization through ion-pair strain

“…Triaminocyclopropeniums (TACs) in particular, show remarkable stability against high temperature and strongly alkaline conditions. 24,25 The synthesis and application of TACs have gained revived interest, and the TACs have found broad uses as ionic liquids, 26,27 electrolytes, 28,29 nitrogen-based ligands, 30 fluorophores, 31 biomaterials, 32 and catalysts. 33–36 An unusual feature of TACs is their electron-rich π systems despite being positively charged cations.…”

A two-step MM and QM/MM approach to model AIEE of aryloxy benzothiadiazole derivatives for optoelectronic applications

“…7 In this context, the design of organic fluorophores for optoelectronic applications has seen tremendous growth in recent years. [8][9][10][11] Organic solar cells derived from fullerenes have been the focal point in organic semiconductors for almost twenty years. 12,13 In the last decade, non-fullerene-based acceptors have become important in organic semiconductor devices due to their tuneable molecular architecture, and more importantly, the discovery of non-fullerene acceptors.…”

Promoting Halogen-Bonding Catalyzed Living Radical Polymerization through Ion-Pair Strain

“…Triaminocyclopropeniums (TACs) in particular, show remarkable stability against high temperature and strongly alkaline conditions. 24,25 The synthesis and application of TACs have gained revived interest, and the TACs have found broad uses as ionic liquids, 26,27 electrolytes, 28,29 nitrogen-based ligands, 30 fluorophores, 31 biomaterials, 32 and catalysts. [33][34][35][36] An unusual feature of TACs is their electron-rich  systems despite being positively charged cations.…”