Self-Assembly of a Highly Emissive Pure Organic Imine-Based Stack for Electroluminescence and Cell Imaging

Abstract

We demonstrated that a purely organic stack, namely, TPE-3-stack, can be assembled in high yield by using dynamic imine chemistry. TPE-3-stack emits strong fluorescence not only in the solid state (ϕ PL = 83%) but also in dilute solutions (e.g., ϕ PL = 82% in DMSO), which is significantly distinct from the case of the aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) chromophores. In addition, it shows high spectral, thermal, and chemical stabilities as well as excellent solubility in common solvents. Therefore, this stack is feasible for fabricating a solution-processed electroluminescent device, which displays brightness over 1000 cd m −2 and a current efficiency up to 2.3 cd A −1 . TPE-3-stack is also demonstrated as a promising fluorescent visualizer for lysosome imaging. Such characteristics of the stack compound were attributed to the efficient suppression of intramolecular rotation and vibration by locking its structure into the rigid framework by means of a self-assembly strategy.

Soluble Congeners of Prior Insoluble Shape‐Persistent Imine Cages

“…Nowadays, shape‐persistent organic cages are mainly synthesized by using reversible condensation reactions, such as by multiple imine bond formation or the generation of boronic esters from the corresponding diols and boronic acids [20–60] . These reactions used are often called dynamic covalent chemistry (DCC) reactions, allowing the system to reach thermodynamic equilibrium by self‐correction mechanisms due to the intrinsic reversibility [5,61,62] .…”

“…Nowadays, shape‐persistent organic cages are mainly synthesized by using reversible condensation reactions, such as by multiple imine bond formation or the generation of boronic esters from the corresponding diols and boronic acids. [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ] These reactions used are often called dynamic covalent chemistry (DCC) reactions, allowing the system to reach thermodynamic equilibrium by self‐correction mechanisms due to the intrinsic reversibility. [ 5 , 61 , 62 ] However, not always is the formed cage also the favored product of thermodynamic equilibrium and the equilibrium needs to be shifted by either removing product by precipitation or, in case of formed water, by Dean‐Stark traps or other scavengers (e. g. molecular sieves).…”

Coordinative-to-covalent transformation, isomerization dynamics, and logic gate application of dithienylethene based photochromic cages

“…In particular, via the synergetic formation of dynamic covalent imine bonds (C]N) and coordination bonds, a variety of fascinating structures have been constructed, including cages, [1][2][3][4][5][6][7][8][9][10][11][12] helicates, [13][14][15][16] capsules, [17][18][19][20] borromeates, [21][22][23] catenanes [24][25][26][27] and rotaxanes. [28][29][30][31] Multi-component self-assembly of pure covalent-organic cage-like architectures with well-dened complexity and integrity has been achieved, [32][33][34][35] but the use of metallo-components may provide further control of the process by preorientation through metal ion coordination. This strategy takes advantage of a predened metal-templated architecture in the formation of multiple imine bonds during the synergistic self-assembly process, and the resulting generated dynamic constituents can be reduced to demetalated non-dynamic organic analogues which are not anymore subject to reversible deconstruction.…”

Host–Guest Recognition and Fluorescence of a Tetraphenylethene‐Based Octacationic Cage

“…For example, Stang and co‐workers developed a series of platinum(II) metallamacrocycles and metallacages based on pyridyl or carboxylic TPEs, which exhibited high emission and multiple colors based on their AIE properties in various solvents . Given the fluorescence property of TPE and its propeller‐like P and M configurations, other TPE‐based cages were further investigated for their gas‐sorption behavior, chiral structure, electroluminescence and cell imaging, and light‐harvesting‐driven catalysis . Unfortunately, these metal/anion‐coordinated or imine‐bonded TPE cages as a single‐molecular platform did not exhibit any effective host–guest recognition, probably owing to electrostatic and steric repulsion effects from metal ions or anions, unstable coordination or reversible chemical bonds, and/or crowed inner spaces between the propeller‐like phenyl rings .…”