Piezofluorochromism in Charge‐Transfer Inclusion Crystals: The Influence of High Pressure versus Mechanical Grinding

Abstract

What was the most significant result of this study?We found ad istinctive piezochromic luminescent response of as eries of intermolecularc harge-transfer crystals and their structural properties are investigated. High-pressure singlecrystal X-ray analysis and TD-DFT calculations clearly suggested that the piezochromic properties are observedb ythe closer arrangement of interfacial distances between charge-transfer crystalsi nduced by high compression. In particular,o ur charge-transfer crystalss how an unusual multichromic feature in which the piezochromic response is reversibly controlled by high pressure over the entire visible region (over 100 nm), whereas the effect of mechanical grinding is negligible. Who designed the cover?This cover artworki sd esigned by Ms. Aria Hisaeda.S he understood our vague image request and drew aw onderful coverThe front cover artwork is provided by the group of Prof. Y. Hisaeda at KyushuU niversity (Japan). The work is in collaboration with the group of Prof. M. Abe and Prof.Y .

Solvation-Enhanced Intermolecular Charge Transfer Interaction in Organic Cocrystals: Enlarged C–C Surface Close Contact in Mixed Packing between PTZ and TCNB

“…2 The second method for tuning the intermolecular CT interaction is the high-pressure method. 29,45,46 The D−A interplanar mixed packing distances become narrower during the compression process, leading to the enhancement of the intermolecular CT interaction and the red-shifts of the spectral bands. 29,45 In certain cases, the D−A mixed packing distance is inversely proportional to the intermolecular CT interaction.…”

“…29,45,46 The D−A interplanar mixed packing distances become narrower during the compression process, leading to the enhancement of the intermolecular CT interaction and the red-shifts of the spectral bands. 29,45 In certain cases, the D−A mixed packing distance is inversely proportional to the intermolecular CT interaction. 2,29,45 Solvent molecules as one of the building components are also fully considered into the structures of OCTCs.…”

“…29,45 In certain cases, the D−A mixed packing distance is inversely proportional to the intermolecular CT interaction. 2,29,45 Solvent molecules as one of the building components are also fully considered into the structures of OCTCs. 13,47,48 Hu et al reported a cocrystal, perylene−TCNB, and they studied the changes of its structure, color, and dramatic shape, while the aromatic solvents (tetrahydrofuran, THF) were accommodated.…”

“…Our results prove that the solvent accommodation enhances the intermolecular CT transition from PTZ to TCNB. 29,45 The in situ Raman spectra of the PTZ power, the TCNB power, the PT solid crystal, and PT-S solid crystal were also investigated at the 633 nm excitation line (Figure 2C). The Raman vibrational bands of CN are located at 2230−2600 cm −1 in TCNB, PT, and PT-S. To clearly understand and identify these peaks, we simulated and assigned the Raman bands of the CN in TCNB, PT, and PT-S as shown in Figures S1, S2, and Table S2.…”

Flexible and Continuous Regulation Promoting Remarkably Emission Enhancement of Planar Triphenylene

“…High-pressure device provides a simple and convenient approach to modulate the optical properties and molecular arrangements continuously, which was applied in the investigations of the structure–property relationship. Generally, as reported in the literature, the adjacent molecules would be driven to squeeze each other during the compression process, in turn significantly enhancing the intermolecular interactions with the geometric deformation to achieve the modulation of the excited-state properties. ,,− Organic crystals usually show the decreased luminescence efficiency when squeezed with the increased external pressure, which was attributed to the formation of new excited-state species − and/or enhanced polarization effect of the excited state. − Meanwhile, the structural planarization would be more likely to occur with the increased external pressure for those organic luminogens with twisted structure in aggregate state, directly causing the markedly large red-shift and decreased emission intensity. Moreover, it is worth noting that, as reported, π-conjugated PAHs such as anthracene and pyrene displayed the monotonically decreased fluorescence intensity under pressure. , …”