288105-07-7

Upstream product

• 623-00-7 4-bromobenzenecarbonitrile 
• 119-61-9 benzophenone 
• 16532-79-9 4-Bromophenylacetonitrile 
• 288105-06-6 2‐(4‐bromophenyl)‐2‐cyano‐1,1‐diphenylethylene 
• 73183-34-3 bis(pinacol)diborane 

Relevant academic research and scientific papers

Synthesis of Fluorene-Bridged Arylene Vinylene Fluorophores: Effects of End-Capping Groups on the Optical Properties, Aggregation Induced Emission

We have synthesized a series of fluorene-based fluorophores, in which a central fluorene core has been modified with different peripheral arylene vinylene substituents that are able to activate aggregation-induced emission (AIE) characteristics. 9,9-Dioctylfluorene doubly end-capped at the 2,7-positions with triphenylethene groups, such as 4-(2,2-diphenylvinyl)phenyl (F1-(2,2)-HTPE) and 4-(1,2-diphenylvinyl)phenyl (F1-(1,2)-HTPE) were synthesized and compared to the tetraphenylethene analogue (F1-TPE). Both F1-(2,2)-HTPE and F1-(1,2)-HTPE glow with a deep blue fluorescence in THF solution with emission maxima (λem) of 426 and 403 nm, respectively. The λem slightly red-shifts in the solid-state to 458 nm for F1-(2,2)-HTPE and 437 nm for F1-(1,2)-HTPE. The fluorescence quantum yields (Φ;F) of F1-(2,2)-HTPE (?F=35.1 %) and F1-(1,2)-HTPE (?F=26.2%) were found to be higher in solution compared to the near quenching of F1-TPE (?F=0.1%). Consequently, this results in weaker AIE-stability of F1-(2,2)-HTPE (αAIE=1.5) and F1-(1,2)-HTPE (αAIE=1.9) compared to F1-TPE (αAIE=125), suggesting that four phenyl groups are necessary for efficient AIE-activity of these fluorene bridged arylene vinylene type materials. In addition, decreasing the steric hindrance around the arylene vinylene moiety by removal of a phenyl ring is another method to decrease the AIE characteristics, in a similar manner to the commonly known ?phenyl-locking?. Non-polar triphenylethenes are poorer AIE materials than their tetraphenylethene analogues. Replacing the hydrogen atom of F1-(2,2)-HTPE with a cyano group affords fluorene end-capped with 2,3,3-triphenylacrylonitrile (F1-TPAN), which boosts the AIE-effect to αAIE=90.5 and red-shifts the solid-state emission (λem=528 nm) with near quenching in THF solution (?F=0.12%). X-ray crystallographic analysis of F1-TPAN indicates that the introduction of cyano groups can not only diminish the intramolecular steric hindrance in comparison of F1-TPE, but also improve the molecular cohesion ability via multiple C-H···N interactions. Four different arylene vinylene substituents attached to the fluorene were synthesized, and the disparities of AIE-effect of these compounds were discussed. The cyano-groups in F1-TPAN will not only reduce the steric congestion of the peripheral phenyl rings, but also appreciably improve the molecular cohesion ability via multiple C-H?N interactions.

Efficient solid emitters with aggregation-induced emission and intramolecular charge transfer characteristics: Molecular design, synthesis, photophysical behaviors, and OLED application

Emissive electron donor-acceptor (D-A) conjugates have a wide variety of applications in biophotonics, two-photon absorption materials, organic lasers, long wavelength emitters, and so forth. However, it is still a challenge to synthesize high solid-state efficiency D-A structured emitters due to the notorious aggregation-caused quenching (ACQ) effect. Though some D-A systems are reported to show aggregation-induced emission (AIE) behaviors, most are only selectively AIE-active in highly polar solvents, showing decreased solid-sate emission efficiencies compared to those in nonpolar solvents. Here we report the triphenylamine (TPA) and 2,3,3-triphenylacrylonitrile (TPAN) based D-A architectures, namely, TPA3TPAN and DTPA4TPAN. Decoration of arylamines with TPAN changes their emission behaviors from ACQ to AIE, making resulting TPA3TPAN and DTPA4TPAN nonluminescent in common solvents but highly emissive when aggregated as nanoparticles, solid powders, and thin films owing to their highly twisted configurations. Both compounds also display a bathochromic effect due to their intramolecular charge transfer (ICT) attribute. Combined ICT and AIE features render TPA3TPAN and DTPA4TPAN intense solid yellow emitters with quantum efficiencies of 33.2% and 38.2%, respectively. They are also thermally and morphologically stable, with decomposition and glass transition temperatures (Td/Tg) being 365/127 and 377/141 °C, respectively. Multilayer electroluminescence (EL) devices are constructed, which emit yellow EL with maximum luminance, current, power, and external quantum efficiencies up to 3101 cd/m2, 6.16 cd/A, 2.64 lm/W, and 2.18%, respectively. These results indicate that it is promising to fabricate high efficiency AIE-ICT luminogens with tunable emissions through rational combination and modulation of propeller-like donors and/or acceptors, thus paving the way for their biophotonic and optoelectronic applications.

Synthesis, morphology, and optical properties of tetrahedral oligo(phenylenevinylene) materials

A novel topological strategy is described for designing amorphous molecular solids suitable for optoelectronic applications. In this approach, chromophores are attached to a tetrahedral point of convergence. Stilbenoid units were covalently linked to tetraphenylmethane, tetraphenyladamantane, or tetraphenylsilane cores using palladium catalyzed coupling methodology. Thus, reaction of E(C6H5X)4 (E = C and adamantane, X = I; E = Si, X = Br) with styrene or 4,4'-tert-butylvinylstilbene under Heck coupling conditions yields the corresponding tetrakis(stilbenyl) (E(STB)4) and tetrakis(4-tert- butylstyrylstilbenyl) (E((t)BuSSB)4) compounds. Similarly, reaction of 1,1- diphenyl-2-(4-dihydroxyboronphenyl)ethene or 2-(4-pinacolatoboronphenyl)-3,3- diphenylacrylonitrile with tetrakis(4-bromophenyl)methane using Suzuki coupling methodology gives tetrakis(4,4'-(2,2-diphenyl-vinyl)-1, 1'- biphenyl)methane (C(DPVBi)4) or tetrakis(4,4'-(3,3-diphenylacrylonitrile)- 1,1'-biphenyl)methane (C(DPAB)4), respectively, in good yields. Compounds with more extended conjugation can also be prepared. Thus, reaction of excess 1-(4'-tert-butylstyryl)-4-(4'-vinylstyryl)benzene with C(C6H4I)4 provides tetrakis(4-(4'-(4''-tert-butylstyryl)styryl)stilbenyl)methane (C(4R-(t)Bu)4) in low yield (~20%). The more soluble analogue, tetrakis(4-(4'-(3,5-di- tert-butylstyryl)styryl)stilbenyl)methane (C(4R-2(t)Bu)4) is prepared similarly using 1-(3',5'-di-tert-butylstyryl)-4-(4'-vinylstyryl)benzene and in better yield (~80%). Alkoxy substituents can also be used to increase solubility. Tetrakis((4-(2',5'-dioctyloxy-4'-styryl)styryl)stilbenyl)methane, C(4R-(OC8H17)2)4, was prepared by treatment of C(C6H4I)4 with excess 2,5-dioctyloxy-1-styryl-4(4'-vinylstyryl)benzene (yield ~73%). The simple stilbenyl-derivatives were found by DSC measurements and powder diffraction experiments to be crystalline compounds. Comparison of single-crystal X-ray diffraction data shows that C(STB)4 and Si(STB)4 form isomorphous crystals. The larger E((t)BuSSB)4, C(DPVBi)4, and C(DPAB)4 compounds readily form amorphous glasses with elevated glass transition temperatures (T(g) = 142190 °C) in the absence of solvent. Extending the conjugation length of the arm leads to more stable glasses. For example, the glass transition temperature of C(4R-(t)Bu)4 was measured at 230 °C. Solution phase optical spectroscopic data of E((t)BuSSB)4 (E = C, adamantane, and Si) are characteristic of the parent distyrylbenzene chromophore. Films, however, show broad and significantly red-shifted emission spectra. In contrast, C(DPVBi)4 gives absorption and emission spectra which are nearly identical between dilute solution phase samples and neat solid films. The emission of C(DPAB)4 is broad and structureless, reminiscent of exciplex or excimer emission. Films of the tetramers with longer arms (C(4R-(t)Bu)4, C(4R- 2(t)Bu)4, and C(4R-(OC8H17)2)4) show emission properties which are dependent on sample history. Annealing the sample at elevated temperature leads to red-shifted emission as a result of better interdigitation between the optically active fragments.