Single‐Benzene‐Based Solvatochromic Chromophores: Color‐Tunable and Bright Fluorescence in the Solid and Solution States

Abstract

The search for structurally simple chromophores with superior fluorescence brightness and aw ide range of solventc ompatibility is highly desirable. Herein, an ew type of single-benzene-based solvatochromic chromophore with as ymmetric bifunctional structure, in whicha zetidine and ethoxycarbonyl moietiess erve as the electron-donating and -withdrawing groups, respectively,i sr eported.T his chromophore exhibits an extraordinary wide range of solventc ompatibility and preserves excellent fluorescence quantum yieldsf rom nonpolar n-hexane to polar methanol and even in water.U nusually,t he symmetric structure of the chromophores hows ad istinct color changef rom bright green to red with increasing solvent polaritya nd possesses large Stokess hifts (l = 132-207nm) in the tested solvents. Moreover,t his single-benzene-based chromophored isplays good photochemical stabilityi nb oth solution and solid states, and even exhibits reversible mechanochromic luminescence.[a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Water-Soluble Single-Benzene Chromophores: Excited State Dynamics and Fluorescence Detection

“…Water used was prepared from Milli-Q water. Diethyl 2,5-di(azetidine-1-yl)terephthalate was synthesized and characterized according to our previous report [ 44 ]. Twenty natural amino acids including arginine (Arg), lysine (Lys), histidine (His), aspartic acid (Asp), glutamic acid (Glu), proline (Pro), tryptophan (Trp), leucine (Leu), alanine (Ala), methionine (Met), glycine (Gly), cysteine (Cys), threonine (The), serine (Ser), tyrosine (Tyr), glutamine (Gln), asparagine (Asn), isoleucine (Ile), valine (Val), and phenylalanine (Phe) were purchased from J&K scientific company and used without further purification.…”

“…Featuring distinct emissive properties as well as simple molecular structures, the chromophores with single-benzene-based skeletons are potentially applied in optoelectronic devices and fluorescence sensing [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. Our group firstly reported the diethyl 2,5-di(azetidine-1-yl)terephthalate derivatives as representative single-benzene chromophores in 2019 [ 44 ]. With small π-conjugated systems, these compounds impressively emit intense luminescence in both solution and solid states.…”

Miniaturized Chemical Tags for Optical Imaging

“…the number and the position of benzoate and azetidine moieties. [21] Similar strategies have also been exploited for other applications, from the preparation of red emissive organic crystals to biomaterials for cell imaging and antibiotic evaluation. [22] Of particular interest in this area, Yuan and co-workers recently described SB-Fluors as single benzene terephthalonitrile-based structures covering the entire visible spectrum and having suitable properties for live cell imaging of mitochondria and quantification of HClO (Figure 2).…”

“…Other approaches to design tunable and miniaturized fluorophores have exploited the functionalization of the simplest aromatic system (i.e., benzene) with variable patterns of electron‐donating and electron‐withdrawing substituents to generate chemically diverse push‐pull systems. For instance, the group of Fang reported solvatochromic fluorophores by simple variation of the number and the position of benzoate and azetidine moieties [21] . Similar strategies have also been exploited for other applications, from the preparation of red emissive organic crystals to biomaterials for cell imaging and antibiotic evaluation [22] .…”

“…For instance, the group of Fang reported solvatochromic fluorophores by simple variation of the number and the position of benzoate and azetidine moieties. [21] Similar strategies have also been exploited for other applications, from the preparation of red emissive organic crystals to biomaterials for cell imaging and antibiotic evaluation. [22] Of particular interest in this area, Yuan and co- Reproduced with permission.…”