A synergy between the push-pull electronic effect and twisted conformation for high-contrast mechanochromic AIEgens.

Mechanochromic (MC) luminogens in response to external stimulus have shown promising applications as pressure sensors and memory devices. Meanwhile, research on their underlying mechanism is still in the initial stage. Here, three pyridinium-functionalized tetraphenylethylenes bearing n-pentyloxy, hydrogen and nitro groups, namely TPE-OP, TPE-H and TPE-NO, are designed to systematically investigate the influence of the push-pull electronic effect and molecular conformation on MC luminescence. Upon anisotropic grinding and isotropic hydrostatic compression, TPE-OP with strong intramolecular charge transfer (ICT) affords the best MC behavior among them. Analysis of three polymorphs of TPE-H clearly indicates that planarization of the molecular conformation plays an important role in their bathochromic shifts under mechanical stimuli. Theoretical calculations also verify that high twisting stress of AIEgens can be released under high pressure. This study presents a mechanistic insight into MC behaviour and an effective strategy to achieve high-contrast MC luminescence.

[1]  I. Shundrina,et al.  2-((9H-fluoren-9-ylidene)methyl)pyridine as a new functional block for aggregation induced emissive and stimuli-responsive materials , 2020 .

[2]  B. Tang,et al.  Self-assembly of AIEgens , 2020 .

[3]  Gang Chen,et al.  Pressure-Induced Blue-Shifted and Enhanced Emission: A Cooper-ative Effect between Aggregation-Induced Emission and Energy-Transfer Suppression. , 2020, Journal of the American Chemical Society.

[4]  B. Tang,et al.  Fluorescent aggregation-induced emission (AIE)-based thermosetting electrospun nanofibers: fabrication, properties and applications , 2019, Materials Chemistry Frontiers.

[5]  M. Yao,et al.  Pressure-Induced Emission Enhancement and Multi-color for 1, 2, 3, 4-tetraphenyl-1, 3-cyclopentadiene (TPC)：Controlled Structure Evolution. , 2019, The journal of physical chemistry letters.

[6]  B. Tang,et al.  Structure, Assembly, and Function of (Latent)-Chiral AIEgens , 2019, ACS Materials Letters.

[7]  Yuguo Ma,et al.  Pressure induced the largest emission wavelength change in a single crystal , 2017, Dyes and Pigments.

[8]  M. Yao,et al.  Pressure-Induced Emission Enhancement and Multicolor Emission for 1,2,3,4-Tetraphenyl-1,3-cyclopentadiene: Controlled Structure Evolution , 2019 .

[9]  B. Tang,et al.  Macrocycles and cages based on tetraphenylethylene with aggregation-induced emission effect. , 2018, Chemical Society reviews.

[10]  Ian D. Williams,et al.  Specific Two-Photon Imaging of Live Cellular and Deep-Tissue Lipid Droplets by Lipophilic AIEgens at Ultralow Concentration , 2018, Chemistry of Materials.

[11]  Zhen Li,et al.  The Influence of Molecular Packing on the Emissive Behavior of Pyrene Derivatives: Mechanoluminescence and Mechanochromism , 2018, Advanced Optical Materials.

[12]  M. P. Aldred,et al.  Recent advances in mechano-responsive luminescence of tetraphenylethylene derivatives with aggregation-induced emission properties , 2018 .

[13]  Ian D. Williams,et al.  Multifunctional AIEgens: Ready Synthesis, Tunable Emission, Mechanochromism, Mitochondrial, and Bacterial Imaging , 2018 .

[14]  J. Lam,et al.  Ionization and Anion-π+ Interaction: A New Strategy for Structural Design of Aggregation-Induced Emission Luminogens. , 2017, Journal of the American Chemical Society.

[15]  Begoña Milián‐Medina,et al.  Twist‐Elasticity‐Controlled Crystal Emission in Highly Luminescent Polymorphs of Cyano‐Substituted Distyrylbenzene (βDCS) , 2017 .

[16]  Zhen Li,et al.  Molecular conformation and packing: their critical roles in the emission performance of mechanochromic fluorescence materials , 2017 .

[17]  R. Dhamodharan,et al.  Tetrakis(trialkylsilylethynylphenyl)ethenes: mechanofluorochromism arising from steric considerations with an unusual crystal structure , 2017 .

[18]  Bo Zou,et al.  Pressure-Induced Emission Enhancement of Carbazole: The Restriction of Intramolecular Vibration. , 2017, The journal of physical chemistry letters.

[19]  Li-Ya Niu,et al.  A Solid‐State Fluorescent Material Based on Carbazole‐Containing Difluoroboron β‐Diketonate: Multiple Chromisms, the Self‐Assembly Behavior, and Optical Waveguides , 2017 .

[20]  Stephen Schrettl,et al.  Mechano- and Thermoresponsive Photoluminescent Supramolecular Polymer. , 2017, Journal of the American Chemical Society.

[21]  Desuo Yang,et al.  Selective Host-Guest Co-crystallization of Pyridine-Functionalized Tetraphenylethylenes with Phthalic Acids and Multicolor Emission of the Co-crystals. , 2017, Chemistry.

[22]  Yuguang Ma,et al.  Rehybridization of Nitrogen Atom Induced Photoluminescence Enhancement under Pressure Stimulation , 2017 .

[23]  Lu Wang,et al.  Organic materials with hydrostatic pressure induced mechanochromic properties , 2016 .

[24]  Zhen Li,et al.  A stable tetraphenylethene derivative: aggregation-induced emission, different crystalline polymorphs, and totally different mechanoluminescence properties , 2016 .

[25]  Yen Wei,et al.  A Novel Mechanochromic and Photochromic Polymer Film: When Rhodamine Joins Polyurethane , 2015, Advanced materials.

[26]  Ryan T. K. Kwok,et al.  Aggregation-Induced Emission: Together We Shine, United We Soar! , 2015, Chemical reviews.

[27]  Yongqiang Dong,et al.  Mechanochromic Luminescence of Aggregation-Induced Emission Luminogens. , 2015, The journal of physical chemistry letters.

[28]  Zejun Xu,et al.  Mechanically Induced Multicolor Change of Luminescent Materials. , 2015, Chemphyschem : a European journal of chemical physics and physical chemistry.

[29]  M. Yao,et al.  Piezochromic luminescence behaviors of two new benzothiazole-enamido boron difluoride complexes: intra- and inter-molecular effects induced by hydrostatic compression. , 2015, Chemical communications.

[30]  Yuguang Ma,et al.  Polymorphic crystals and their luminescence switching of triphenylacrylonitrile derivatives upon solvent vapour, mechanical, and thermal stimuli , 2015 .

[31]  Minjie Li,et al.  Dynamic behavior of molecular switches in crystal under pressure and its reflection on tactile sensing. , 2015, Journal of the American Chemical Society.

[32]  Guochun Yang,et al.  Organic Polymorphs: One‐Compound‐Based Crystals with Molecular‐Conformation‐ and Packing‐Dependent Luminescent Properties , 2014, Advanced materials.

[33]  Bingbing Liu,et al.  Luminescence Properties of Compressed Tetraphenylethene: The Role of Intermolecular Interactions. , 2014, The journal of physical chemistry letters.

[34]  Wei Huang,et al.  Smart responsive phosphorescent materials for data recording and security protection , 2014, Nature Communications.

[35]  Zhiyong Ma,et al.  Mechanically induced multicolor switching based on a single organic molecule. , 2013, Angewandte Chemie.

[36]  Hiroyasu Sato,et al.  Distinct responses to mechanical grinding and hydrostatic pressure in luminescent chromism of tetrathiazolylthiophene. , 2013, Journal of the American Chemical Society.

[37]  N. Kitamura,et al.  Mechanical stimulation and solid seeding trigger single-crystal-to-single-crystal molecular domino transformations , 2013, Nature Communications.

[38]  Jia-rui Xu,et al.  Recent advances in mechanochromic luminescent metal complexes , 2013 .

[39]  Ian D. Williams,et al.  Synergy between Twisted Conformation and Effective Intermolecular Interactions: Strategy for Efficient Mechanochromic Luminogens with High Contrast , 2013, Advanced materials.

[40]  G. Ruggeri,et al.  Dye-containing polymers: methods for preparation of mechanochromic materials. , 2013, Chemical Society reviews.

[41]  张艺,et al.  Recent advances in mechanochromic luminescent metal complexes , 2013 .

[42]  Lijuan Wang,et al.  Piezochromic luminescence based on the molecular aggregation of 9,10-bis((E)-2-(pyrid-2-yl)vinyl)anthracene. , 2012, Angewandte Chemie.

[43]  T. Mutai,et al.  Solid-state luminescence of tetraphenylpyrene derivatives: mechano/vapochromic luminescence of 1,3,6,8-tetra(4′-carboxyphenyl)pyrene , 2012 .

[44]  Jian Wang,et al.  Click synthesis, aggregation-induced emission, E/Z isomerization, self-organization, and multiple chromisms of pure stereoisomers of a tetraphenylethene-cored luminogen. , 2012, Journal of the American Chemical Society.

[45]  Jia-rui Xu,et al.  Recent advances in organic mechanofluorochromic materials. , 2012, Chemical Society reviews.

[46]  Takashi Kato,et al.  Brightly tricolored mechanochromic luminescence from a single-luminophore liquid crystal: reversible writing and erasing of images. , 2011, Angewandte Chemie.

[47]  Yongqiang Dong,et al.  Reversible Switching of the Emission of Diphenyldibenzofulvenes by Thermal and Mechanical Stimuli , 2011, Advanced materials.

[48]  Liang Han,et al.  Multi-Stimuli-Responsive Fluorescence Switching of a Donor−Acceptor π-Conjugated Compound , 2011 .

[49]  Jia-rui Xu,et al.  Piezofluorochromism of an aggregation-induced emission compound derived from tetraphenylethylene. , 2011, Chemistry, an Asian journal.

[50]  Dongho Kim,et al.  Multistimuli two-color luminescence switching via different slip-stacking of highly fluorescent molecular sheets. , 2010, Journal of the American Chemical Society.

[51]  Guoqing Zhang,et al.  Polymorphism and reversible mechanochromic luminescence for solid-state difluoroboron avobenzone. , 2010, Journal of the American Chemical Society.

[52]  Takashi Kato,et al.  Mechanically induced luminescence changes in molecular assemblies. , 2009, Nature chemistry.

[53]  Jong Won Chung,et al.  Shear- and UV-induced fluorescence switching in stilbenic pi-dimer crystals powered by reversible [2 + 2] cycloaddition. , 2009, Journal of the American Chemical Society.

[54]  Mitchell T. Ong,et al.  Force-induced activation of covalent bonds in mechanoresponsive polymeric materials , 2009, Nature.

[55]  Takashi Kato,et al.  Stimuli-responsive luminescent liquid crystals: change of photoluminescent colors triggered by a shear-induced phase transition. , 2008, Angewandte Chemie.

[56]  T. Mutai,et al.  Material design for piezochromic luminescence: hydrogen-bond-directed assemblies of a pyrene derivative. , 2007, Journal of the American Chemical Society.

[57]  Hiroyuki Satou,et al.  Reproducible on–off switching of solid-state luminescence by controlling molecular packing through heat-mode interconversion , 2005, Nature materials.

[58]  P. McMillan.  Chemistry of materials under extreme high pressure-high-temperature conditions. , 2003, Chemical communications.

[59]  H S Kwok,et al.  Aggregation-induced emission of 1-methyl-1,2,3,4,5-pentaphenylsilole. , 2001, Chemical communications.

[60]  A. Jayaraman,et al.  Diamond anvil cell and high-pressure physical investigations , 1983 .

[61]  Stanley Block,et al.  An Optical Fluorescence System for Quantitative Pressure Measurement in the Diamond‐Anvil Cell , 1973 .