C₃-Symmetric Propeller-like Phenanthridine Derivative with Multiple Write-In Modes for Programmable Anti-Counterfeiting

Abstract

Multistimuli-responsive fluorescent molecules (PF-B and PF-N) with logically programmable states are synthesized, which utilize a phenyl ring and a nitrogen atom, respectively, as the center connected with three isolated electron-accepting phenanthridine units. Both PF-B and PF-N exhibit fluorescence color changes to trifluoroacetic acid, Al 3+ , Fe 2+ , rigidifying polymer matrix, and heat, resulting in five write-in modes. Meanwhile, PF-N presents a larger bathochromic shift than that of PF-B upon applying an identical stimulus, beneficial from its intramolecular charge transfer (CT) character. The multiple stimulus-responsive feature endows PF-B and PF-N with flexible and diverse applications, including rewritable and security printing, and multiple optical outputs for anti-counterfeiting. More importantly, the response of the fluorophores depends not only on the present stimulus but also on the sequence of past stimuli. Additionally, the build-in reversibility and irreversibility of their responses to different stimuli remarkably diversify the outputs, leading to a well-programmed anti-counterfeiting scheme based on "sequential + OR" logic gates for the first time. This work not only provides a feasible strategy to develop multiple stimuli-responsive luminescence materials at the molecular level but also offers a general design principle of logic schemes for advanced anti-counterfeiting and data protection.

In Situ Optical Detection of Amines at a Parts-per-Quadrillion Level by Severing the Through-Space Conjugated Supramolecular Domino

“…Similarly, PTF2, 42 M2, 51 or T1 52 containing multiple phenanthridine units could also form CTCs with pPFPA, as evidenced by their obviously redshifted emissions at high pPFPA concentrations (Figure 2c−e). It should be noted that T1 exhibits a typical aggregation-induced emission (AIE) behavior and therefore is barely emissive in solution before mixing with pPFPA.…”

Stimuli-fluorochromic smart organic materials

“…The pH-fluorochromic materials, which can display remarkable transformations in emission in response to pH values or acid/ base, 46,47,67,71,[102][103][104]126,132,[164][165][166][167][168][169][170] have been demonstrated to show potential applications in environmental monitoring and acid/ base sensors due to their fast response rate, high contrast, high sensitivity and reversibility. 90,103,144,167 In generally, acid/baseinduced protonation/deprotonation can lead to variations in molecular structures, 85,88,108,156,157 ICT 90,102,144,167 and ET process 280 as well as intermolecular interactions such as p-p stacking 108 and hydrogen bonding, 108 resulting in the switching of the emission properties of pH-fluorochromic materials.…”

“…43), 90,103,144,167 carboxyl groups 108 as well as heterocyclic molecules such as spiropyran 85,88,156,157 and fluorescein isothiocyanate 108 that are sensitive to acid/alkali can be introduced into the existing chromophores to obtain the desired smart materials. So far, not many reports on pH-fluorochromic materials based on organic molecules, 41,46,67,71,103,126,132,169 have been published; therefore, we here will discuss several typical examples according to the pH-fluorochromic mechanisms. 88,102,132,144,157,167 The most commonly applied design strategy is to introduce ionizable aromatic or aliphatic amines into chromophores.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] Among them, stimuli-fluorochromic smart materials (SFSMs), whose photoluminescence properties can be switched by applying different external stimuli, have attracted tremendous attention due to their highly sensitive response and easy visualization. [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] As an example of advanced functional materials, stimuli-fluorochromic smart materials exhibit great application potential for applications such as sensors, 22,26,[32][33][34][35][36][37][38][39][40][41][42][43] information storage, [44][45][46][47] bioimaging,…”

“…Over the last few decades, a myriad of organic p-conjugated solids with diverse stimuli-fluorochromic properties and functions, including SFCSs that are mechano-fluorochromic, 13,14,61,121-124 thermo-fluorochromic, 46,63,64,109,123,125 solvo-fluorochromic, 27,[126][127][128][129][130][131] pH-fluorochromic, 41,47,67,71,108,132 photo-fluorochromic, 133,134 humidity-fluorochromic, 56,63,87,99,107,109,135 electro-fluorochromic, [73][74][75]136,137 and ion-fluorochromic, [68][69][70]89,138 have been…”