Mechanofluorochromic Anthryl Phosphonate/Benzoic Acid Cocrystals with a Large Blue Shift: The Role of P=O⋅⋅⋅H Interactions

Abstract

Organophosphonates have a rich and diverse chemistry, but their mechanofluorochromic features have rarely been documented. Herein, we report on cocrystals of anthranylphosphonate with (E)‐4‐(2‐(anthracen‐9‐yl)vinyl)benzoic acid that exhibit reversible mechanofluorochromic properties with large blue shifts. Anisotropic grinding (or pressure of just 25 kPa) maintains the co‐crystals emission features but leads to a pronounced 59 nm (2087 cm−1) blue‐shift. Such an impressive blue‐shift for a cocrystal has not been reported to date. The underlying causes for the blue‐shift were validated by X‐ray diffraction (powder and single crystal) studies and Hirshfeld surface analysis. Twisted molecular conformations and P=O⋅⋅⋅ H/C=O⋅⋅⋅H/C⋅⋅⋅H noncovalent interactions afford molecular arrangements via slip‐stacks with two different pitch angles and relatively larger interlayer distances. The new compound was established as a potential medium for optical recording and security display.

Flanking-donor-controlled diversity in mechanical-force-induced reversible fluorochromism and enhanced emission for carboxylic acid and ester linked solid-state emitters

“…The molecular sheets with a considerably high interlayer distance and suitable pitch angle would be susceptible to disruption of the molecular stacking by a small mechanical force. 35 Furthermore, the applied mechanical force could quickly destroy the weaker C⋯H interactions, disturbing the complete layered structure built by the intermolecular H-bonding. In a nutshell, the dimeric form of the carboxylic acid group supports the formation of the layered structure with a pitch angle of 63° and long interlayer distances.…”

Concentration-Guided Visual Detection of Multiphase Aliphatic Biogenic Amines through Amine–Phenol Recognition Using a Dual-State Emitter

“…Moreover, purely organophosphonate-based dual-state emitters are considerably rare. 41,42 Typically, we deliver multiple solid-state emitters via Horner−Wadsworth−Emmons reactions with suitable phosphonates as precursors. 43−46 In contrast, the precursor phosphonate molecule itself is designed to emit in both solution and the solid state strongly and offers a unique approach to detect BAs selectively at an ultralow concentration in the liquid and concentration-controlled detection of BAs (especially 1,3-diaminopropane, 1,3-DAP) in the vapor phase.…”

Solution and Solid-State Emissive Organophosphonates with High-Contrast Reversible Mechanofluorochromism: Beyond the Classical Frameworks

“…27−29 Among numerous molecules with MFC features, organophosphonates are hardly recognized due to the lack of solidstate emitting features. 30,31 Amidophosphonate A (Figure 1) was only reported with a 10−40 nm red-shifted MFC feature with inadequate investigations [no solid-state quantum yield (Φ f ) shifting, phase transition, change in the crystallinity and thermal stability (Figure 1)]. 30 The MFC feature from A mainly originated from excimer and change in intramolecular interactions, but the involvement of P=O•••HN− was not documented.…”

“…30 Recently, we recognized a phosphonate cocrystal B to exhibit blue-shifted MFC features, while only phosphonate was blue-emissive in the solid but MFC-inactive. 31 The thermal stability of the molecules is vital for optoelectronic applications; hence, phosphonates as small molecules would be the best choice. To our awareness, this is the first phosphonate molecule that can emit in both solution and solid states and display highcontrast MFC.…”

“…The MFC feature from A mainly originated from excimer and change in intramolecular interactions, but the involvement of P=O···HN– was not documented . Recently, we recognized a phosphonate cocrystal B to exhibit blue-shifted MFC features, while only phosphonate was blue-emissive in the solid but MFC-inactive . The thermal stability of the molecules is vital for optoelectronic applications; hence, phosphonates as small molecules would be the best choice.…”