Five phenylethyne(p-alkoxyphenyl isocyanide)gold(I) complexes with different alkyl chains (OR) in the para-position of the phenyl isocyanide have been successfully synthesized [where R = CH3 (5a), C2H3 (5b), C4H9 (5c), C6H13 (5d), and C10H21 (5e)] and structurally characterized by H-1 NMR, C-13 NMR, and HRMS. To our surprise, the as-prepared powders of these complexes exhibited different emission colors. The diversity of their mechanochromic luminescence properties has been investigated with photoluminescence spectroscopy, powder X-ray diffraction (XRD) analysis, and single-crystal XRD analysis. The results indicated the presence of weak intermolecular interactions in their crystal structures, and different alkyl chains had obvious impacts on their stacking arrangements and optical behavior. The luminescence quantum yield of 5c was as high as 49.3% in the solid state. Complexes 5a-5e each showed luminescence quenching after grinding.

A dithieno[3,2-b:2′,3′-d]pyrrole-based luminogen 1 has been synthesized by appending two twisted triphenylamine units to the rigid conjugated dithieno[3,2-b:2′,3′-d]pyrrole core. This compound exhibits reversible mechanochromic luminescence in the solid state and near-infrared electrochromic switching behavior in solution. A reversible switching in fluorescence color between yellow-green and green can be observed through mechanical grinding and vapor fuming of solid powdered 1, which involves an interconversion between a crystalline form and an amorphous phase according to X-ray diffraction analysis. The associated oxidized species of 1 show intense redox-switchable near-infrared absorption and different fluorescence colors in solution in spectroelectrochemical and luminescence measurements. Density functional theory calculations have confirmed that there is considerable electron delocalization between the dithieno[3,2-b:2′,3′-d]pyrrole linker and two triphenylamine redox-active termini during the oxidation process.

The research efforts on oligoacene systems are still relatively limited mainly due to the synthetic challenge and the extreme instability of longer acenes. Herein, these two issues have been overcome through elaborative modification and the stable pentacene species has been successfully synthesized. Additionally, a series of bis(diarylamino) compounds linked by variable-length oligoacene bridges ranging from one to five fused rings (benzene ( 1a ), naphthalene ( 1b ), anthracene ( 1c ), tetracene ( 1d ) and pentacene ( 1e )) have been prepared to probe the effect of the extent of π -conjugation on the electron transfer properties. Compound 1c exhibits a high planarity between the anthracyl bridge and the two nitrogen cores and the molecular packing shows a two-dimensional herringbone characteristic. Combined studies based on electrochemistry and spectroelectrochemistry demonstrate that (i) the electronic coupling across the oligoacene linkers between two diarylamine termini exponentially decrease with a moderate attenuation constant ( β ) of 0.14 Å −1 in these length-modulated systems and (ii) the associated radical cations [ 1a ] + –[ 1e ] + are classified as the class II Robin–Day mixed-valence systems. Furthermore, density functional theory (DFT) calculations have been conducted to gain insight into the nature of electron transfer processes in these oligoacene systems.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A series of constitutional isomers containing dinuclear gold(I) units were designed, synthesized and characterized using IR spectrometry, NMR spectroscopy and elemental analysis. The aggregation-induced emission (AIE) characteristics of the complexes were investigated by photoluminescence (PL) and UV/Vis spectroscopy. The results indicated that gold(I) complexes 1-3 exhibited significant AIE phenomena. PL spectroscopy, used to probe their solid-state mechanochromic properties, suggested ortho-isomer luminogen 1 exhibited reversible mechanochromic fluorescence, whereas meta-isomer luminogen 2 showed switchable mechanical force-induced luminescence enhancement behavior. No mechanochromism behavior was observed for para-isomer luminogen 3. Powder X-ray diffraction indicated that the morphology phase conversion between crystalline and amorphous states is responsible for the mechanochromism or mechanical force-induced emission enhancement characteristics.

Seven gold(i) complexes with alkyl chains of different lengths were synthesized, these luminogens exhibited AIE and mechanochromism characteristics.