“CinNapht” dyes: a new cinnoline/naphthalimide fused hybrid fluorophore. Synthesis, photo-physical study and use for bio-imaging

Abstract

Six-membered-diaza ring of cinnoline has been fused on naphthalimide dye to give a donor–acceptor system called CinNapht.

Tunable Naphthalimide/Cinnoline‐Fused (CinNapht) Hybrid Dyes for Fluorescence Imaging in Living Cells

“…[6c, 20] The Judolidine motif seems also convenient as proved by the acceptable brightness of CinNapht 8c associated with a red-shifted emission. In order to confirm the solvatochromism effect observed in the previous study [17] , the photophysical properties of the compounds have also been investigated more polar solvents. The measurements in DMSO (Table 1) confirmed a systematic bathochromic shift of the emission wavelengths characterizing the ICT fluorophores showing a marked solvatochromism.…”

“…The N-alkylated phthalimides 3 were synthesized in a two steps process from 4-amino-1,8-naphthyl anhydride as previously reported. [17] Scheme 1. Synthesis route and structure of CinNapht analogues.…”

“…CHCl3 489 [e] 15 700 [e] 566 [e] 2 782 [e] 0.25 [e] 3 925 [e] DMSO 496 [e] 15 500 [e] 682 [e] 5 499 [e] 0.06 [e] 930 [e] PBS [c] Relative QY determined at 25 °C using [Ru(bpy)3]Cl2 (QY = 0.04 in air Saturated H2O), All compounds QYFl were determined using excitation wavelength at 470 nm except for 8c (Exc = 490 nm) and compound 8d (Exc = 450 nm) [18] [d] Brightness was calculated using the formula: Brightness = QYFl × max, [e] Previously reported values [17] , [f]. Poor solubility could not enable to obtain an accurate value.…”

“…[13] Efforts to develop fused hybrid fluorophores based on a naphthalimide structure have also been reported (Figure 1). [14] Inspired by work describing "covalent-assembly" probes [15] resulting in the formation of cinnoline incorporating fluorophores, [16] we recently published the study of a fused hybrid structure involving a naphthalimide and a cinnoline, called CinNapht [17] . We showed that the extended conjugation of the Naphthalimides resulted in a bathochromic shift of the absorption and emission wavelengths of the fluorophores while preserving a high Stokes shift.…”

Preparation of 3-Substituted Isoindolin-1-one, Cinnoline, and 1,2,4-[e]-Benzotriazine Derivatives

“…In addition, some analogues of these heterocycles have demonstrated electro-optical activities, and others have been used as dyes ( Figure 2 ). 15 …”