Expanding the Breadth of 4‐Amino‐1,8‐naphthalimide Photophysical Properties through Substitution of the Naphthalimide Core

Abstract

Fluorescent sensors that illuminate specific molecules and chemical events allow the selectivea nd sensitive study of the cellular environment. At the centre of this technology lies the fluorescent reporter molecule, and it is therefore crucial to provide ab readth of fluorophores with varying photophysical and biological behaviour.4 -Amino-1,8naphthalimides are commonly employed in fluorescent sensors, but the narrow range of structurald erivativesl imits versatility of application.H ere we report the synthesis and investigation of as et of twelve 4-amino-1,8-naphthalimides bearinga na dditional substituent on the aromatic core. Pho-tophysical characterisation and time-dependent density functional theory studies provided insights into the structure-photophysical property relationships of these derivatives, which show an expanded range of emissionw avelengths and other photophysical properties. These compounds coulda ll be visualised within cells by confocal microscopy,s howingc ytoplasmic or lipid droplet localisation. Our studies have demonstratedt hat simple structural modification of 4-amino-1,8-naphthalimides provides derivatives with considerable breadtho fb ehaviour that lend valuable versatility to the design of fluorescents ensors.

The Remarkable Effect of Halogen Substitution on the Membrane Transport of Fluorescent Molecules in Living Cells

“…[1] Particularly,s mall-molecule-based fluorescent probes have found diverse applications in the areas of cell biology,d rug discovery,chemical biology, and clinical diagnosis. [6] Thet wo-photon fluorescent probe for the detection of formaldehyde, [7] the lysosometargetable probe for monitoring the endogenous nitric oxide (NO), [8] the solvatochromic fluorophore for the development of ap rotein-based pH sensor, [9] the ratiometric fluorescent probe for monitoring the mitochondrial NO level, [10] the pantetheine probe for the visualization of the chain-flipping mechanism in fatty-acid biosynthesis [11] represent af ew selected examples of fluorescent probes that have been employed successfully for cellular applications.Inthis paper, we report for the first time that as imple substitution of hydrogen atoms with halogens remarkably enhances the cellular uptake of naphthalimide-based fluorescent molecules in mammalian cells.T his study also suggests that halogen bonding may facilitate the active transport of halogenated compounds,p articularly iodinated compounds,a cross the plasma membrane. [6] Thet wo-photon fluorescent probe for the detection of formaldehyde, [7] the lysosometargetable probe for monitoring the endogenous nitric oxide (NO), [8] the solvatochromic fluorophore for the development of ap rotein-based pH sensor, [9] the ratiometric fluorescent probe for monitoring the mitochondrial NO level, [10] the pantetheine probe for the visualization of the chain-flipping mechanism in fatty-acid biosynthesis [11] represent af ew selected examples of fluorescent probes that have been employed successfully for cellular applications.Inthis paper, we report for the first time that as imple substitution of hydrogen atoms with halogens remarkably enhances the cellular uptake of naphthalimide-based fluorescent molecules in mammalian cells.T his study also suggests that halogen bonding may facilitate the active transport of halogenated compounds,p articularly iodinated compounds,a cross the plasma membrane.…”

“…[2] Although al arge number of smallmolecular fluorescent probes have been developed for various cellular applications, [3][4][5] the mechanisms by which these molecules enter the cells are not well understood in many cases.F luorescence probes based on 4-amino-1,8naphthalimide have attracted significant attention as these compounds can be synthesized in high yields from readily available starting materials and their solubility and fluorescence properties can be altered by substitution at the amino and imide moieties ( Figure 1). [6] Thet wo-photon fluorescent probe for the detection of formaldehyde, [7] the lysosometargetable probe for monitoring the endogenous nitric oxide (NO), [8] the solvatochromic fluorophore for the development of ap rotein-based pH sensor, [9] the ratiometric fluorescent probe for monitoring the mitochondrial NO level, [10] the pantetheine probe for the visualization of the chain-flipping mechanism in fatty-acid biosynthesis [11] represent af ew selected examples of fluorescent probes that have been employed successfully for cellular applications.Inthis paper, we report for the first time that as imple substitution of hydrogen atoms with halogens remarkably enhances the cellular uptake of naphthalimide-based fluorescent molecules in mammalian cells.T his study also suggests that halogen bonding may facilitate the active transport of halogenated compounds,p articularly iodinated compounds,a cross the plasma membrane.…”

Naphthalimide Dyes with Orthogonal Functional Groups for “Click” Chemistry: Attachment to Solid Supports and Applications in Drug Allergy Diagnosis

“…A derivate of 4‐amino‐1,8‐naphthalimide was chosen for the model presented in Figure b on account of its facile modification, outstanding photostability, and large Stokes shift . The fluorescent molecule 2 was reached through the synthetic route showed in Figure a (see Supporting Information for complete details).…”

Neues Mitglied der Deutschen Akademie der Naturforscher Leopoldina: Michael Sattler / Australian Museum Eureka Prizes: T. Maschmeyer und E. J. New / Alfred C. Egerton Gold Medal: K. Kohse‐Höinghaus

“…In diesem Jahr erhielt sie eine Stelle als Associate Professor an der University of Sydney. Chemistry—A European Journal veröffentlichte kürzlich einen Beitrag von ihr über die photophysikalischen Eigenschaften von 4‐Amino‐1,8‐naphthalimiden …”