Organic Crystals with Tunable Emission Colors Based on a Single Organic Molecule and Different Molecular Packing Structures

Abstract

The design and synthesis of organic optical and electronic materials have attracted much attention because of their possible applications in organic electroluminescent devices (organic light-emitting diodes, OLEDs), organic thin-film transistors (OTFTs), and organic photovoltaic diodes (OPVDs). For solid organic materials, the constituent molecules may form strong intermolecular interactions and assemble into packed structures, with the result that the properties of these materials are governed by the whole collective rather than by individual molecules. [1][2][3][4][5][6][7] The performance of organic moleculebased devices strongly depends on the molecular-assembly structures. Therefore, understanding and controlling molecular arrangements in the solid state are fundamental issues for obtaining the desired chemical and physical properties of a material.[8] The increasing demand for new molecular organic functional materials requires the relationship between molecular packing characteristics and optical and electronic properties to be elucidated, which will enable the development of new strategies for developing high-performance organic materials. Although considerable progress has been made in organic luminescent materials with different molecular structures, [9][10][11][12][13][14][15][16][17][18][19][20][21] it is still essential to achieve a molecular-level understanding of the relationship between the molecular packing characteristics of organic materials and the resulting optical properties. [22][23][24][25][26] Hydrogen bonding and p_p stacking are two kinds of important intermolecular interactions for the construction of functional supramolecular systems. Furthermore, noncovalent intermolecular interactions such as hydrogen bonding, p_p interactions, and the presence of solvent molecules are all able to influence strongly the final packing structure, making polymorphism more probable. [27][28][29][30] Different polymorphs may have very different physical and chemical properties. The molecular assembly of optical and electronic materials based on the collective interactions of hydrogen bonding and p_p stacking remain a challenge in the field of organic functional materials.In this communication, we present methods of using the organic molecule 3(5)-(9-anthryl)pyrazole (ANP) (Scheme 1) as building blocks to construct different luminescent single crystals (polymorphs) based on hydrogen bonding and p_p stacking interactions. The relationship between the molecular packing and the optical properties of the obtained crystals are also reported.ANP was conveniently prepared in high yield from 9-acetylanthracene by a procedure analogous to the synthesis of other 3(5)-arylpyrazoles reported previously. [31,32] The absorption and emission spectra of ANP in chloroform solution are shown in Figure 1, and both the absorption and emission spectra exhibit the typical features of the anthracene chromophore. First, two kinds of ANP single crystals were grown by vacuum sublimation. ANP powder was heated to 433 K (±1.5 K) and...

p-Carboxyl-N-salicylideneanilines: Simple but efficient chromophores for one-dimensional microrods with aggregation-induced emission enhancement (AIEE) characteristics

“…AIEE compounds such as silole derivatives [25][26][27], arylethene derivatives [28], 1-cyano-trans-1,2-bis(4 0 -methylbiphenyl)ethylene (CN-MBE) [29,30], and 1,4-di[(E)-2-phenyl-propenyl]benzene (PPB) [31] have been reported, and some of them have been successfully applied as fluorescence/biological probes and optoelectronic devices [32][33][34][35][36]. It is notable that the design principle for most AIEE compounds is mainly focused on the restriction of rotation of C-C single bond connecting two or more p-conjugated moieties [25][26][27][28][29][30][31][37][38][39][40][41][42].…”

Multicolor Emission on Prepatterned Substrates Using a Single Dye Species

“…[22,23] Specifically, organic crystals with tunable emission colors based on different molecular packing structures were reported recently. [24] Depending on the aggregation states, the color change could cover a wide spectral region. [25] A deformation-induced color change in the photoluminescence of a polymer-blend film doped with dye molecules has also been demonstrated.…”

A stimuli-responsive double-stranded digold(i) helicate

“…Intermolecular π···π interactions, 20 however, can have dramatic impact on the solid-state luminescence properties and can lead to red shifts in the emission spectra. 7 In I B crystal, the [Au 2 L 2 ] 2+ helicates are packed into head-to-tail fashion to form columnar stacks (Fig. 8a) based on π···π interactions between the xanthene chromophore and phenyl 25 groups (centroid-centroid distance of 5.08 and 5.84 Å, for details see Figure S14 and Table S4 in the Supporting Information).…”

“…One approach to 35 achieve various emission colours from the same compound is the existence of different crystalline and amorphous phases displaying different molecular conformations or packings. [6][7][8] Generally, the molecular packing is controlled by subtle interplay between different noncovalent intermolecular interactions among 40 the components, such as cations, anions, solvents, etc. Therefore, variations in noncovalent intermolecular interactions between the building blocks of a crystal could be an effective strategy to finetune its solid-state luminescent properties.…”