Interconvertible multiple photoluminescence color of a gold(i) isocyanide complex in the solid state: solvent-induced blue-shifted and mechano-responsive red-shifted photoluminescence

Abstract

We report the first example of a mechanochromic compound that can switch between four individual types of photoluminescence in the solid state.

Heat‐Resistant Mechanoluminescent Chromism of the Hybrid Molecule Based on Boron Ketoiminate Modified Octasubstituted Polyhedral Oligomeric Silsesquioxane

“…[52] The iodine groups in octasubstituted iodophenyl-POSS( I-POSS) [53] werec onverted into the boronic ester groups in the presenceo fnBuLi and the boronic ester reagent. Metal-catalyzed Suzuki-Miyaura cross couplings between iodo-substituted boron ketoiminate and I-POSS were carriedo ut in the presence of S-Phos and [Pd 2 (dba) 3 ]. The chemical structure of the product was determined by 1 H, 13 C, 11 B, and 29 Si NMR spectroscopy and mass spectrometry.I nt he 29 Si NMR spectrum (Figure S1 in the Supporting Information), as ignificant sharp signal was observeda td = À83.5 ppm that was attributable to the T8 silica cage.…”

“…The luminescentp roperties of organicf luorophores in the solid state can be occasionally affected by molecular distributions and morphology.W hen luminescent chromism was induced by mechanical stimuli, such as pressing,c rushing, and grinding,t hese molecules are classified as mechanoluminescent chromic (MLC) compounds. [1][2][3][4][5][6][7] Because of the potential versatility of MLC materials, such as for optical recording/ memory devices, [8] pressure indicators, [9] stress detectors with polymers, [10] and bioprobes for monitoring microenvironmental changes, [11,12] not only the development of MLC compounds, but also modulation of luminescent properties, such as color, intensity,a nd chromism direction,are hot topics with high relevance.H owever,b ecause most conventional luminescent dyes intrinsically show weake mission in the solid state due to aggregation-causedq uenching (ACQ), there are limited numbers of molecular skeletons with clear MLC behavior.I ndeed, it is still challengingt op recisely regulate MLC properties according to preprogrammed design.O ne of the promising candidates to produce MLC compounds with functional tunability is the class of aggregation-inducede mission [13][14][15][16][17][18][19][20] (AIE)-active molecules, which can show bright emission only in the aggregated state. [21] In particular, recent studies reported that vari-ous types of solid-state fluorescent materials with stimuliresponsive fluorescentc hromism involving MLC could be prepared based on the regulation of electronic conjugation through AIE-active organoboron complexes.…”

Mechanoresponsive Luminescent Molecular Assemblies: An Emerging Class of Materials

“…Copyright 2012, The Chemical Society of Japan. Part (c) is adapted with permission . Copyright 2015, The Royal Society of Chemistry.…”

“…Recently, Seki and Ito et al have reported that a gold(I) isocyanide complex 52 (Figure c) forms four individual solid states with different photoluminescence colors, which are interconvertible by treatment with acetone and mechanical shearing (Figure c) . The relatively high polarity of 52 may help the formation of weak interactions with acetone and enable solvent inclusion/release processes.…”

Reversible tricolour luminescence switching based on a piezochromic iridium(iii) complex

“…5 Compared to bicolour switching materials, multicolour counterparts have enhanced colour contrast and patterning, which is beneficial for the practical applications noted above. Reported multicolour examples include small organic molecules, 6 liquid crystals, 7 amphiphilic molecules, 8 multi-component assemblies, 9 polymers, 10 gold(I) 11 and platinum(II) 12 complexes.…”