Room‐Temperature Phosphorescence Invoked Through Norbornyl‐Driven Intermolecular Interaction Intensification with Anomalous Reversible Solid‐State Photochromism

Abstract

Herein, norbornyl (NB), ab ulkya nnular nonconjugated spacer,i sm elded into p systems to construct two groups of ladder-type room-temperature phosphorescence (RTP) luminogens.T he effect of the NB on p-p interactions, packing modes and RTP performance is explored systematically.The experimental and computational results demonstrate the versatility of NB in reducing p-p distances and synergistically intensifying the intermolecular interactions,w hich not only induces intersystem crossing from S 1 to T n but also diminishes the nonradiative decayo ft riplet excitons.I mpressively,1 800-fold phosphorescence lifetime enhancement is achieved in comparison with the reference compounds without NB.T he molecular packing and RTPp erformance can be further modulated by the length of the backbones and terminal end-groups.Itisquite peculiar that NB-annulated phthalic acid exhibits reversible photochromism in the solid state,likely due to the formation of persistent radical pairs.Our study paves an ingenious avenue towards enhancing intermolecular interactions and provides significant implications for ab etter comprehensive understanding of the origin of their RTPa nd the inherent photophysical mechanism.

Metal‐Free Organic Luminophores that Exhibit Dual Fluorescence and Phosphorescence Emission at Room Temperature

“…In addition, the applications of the dual‐emissive compounds, which include quantitative imaging of tumour hypoxia, in vivo camera wound imaging, RGB‐channel‐based camera imaging, ratiometric sensing of oxygen and temperature, emission‐lifetime‐based data encryption and decryption, white‐light‐emission, and OLED, are also presented. Meanwhile, several dual‐emissive compounds that cannot be classified into the categories exist, that include (pinacolatoboryl)arenes, [63] boron cluster, [64] 1‐benzyl‐4,4′‐bipyridinium, [65] 2,5‐disiloxy‐1,4‐bis(diarylphosphinyl)benzene, [45] difluorotetrakis(arylthiol)benzene, [66] brominated fluorenes, [67] naphthalimides, [68] norbornane‐annulated arenes, [69] tetrakis(aryloxy)phthalonitriles, [2c] N ‐alkyl‐ and N ‐benzoylcarbazoles, [70] N , N ′‐di(1‐naphthyl)‐ N , N ′‐di‐phenyl‐(1,1‐biphenyl)‐4,4‐diamine, [71] polyimides, [72] N ‐(4‐trifluoromethylphenyl)‐4‐bromophthalimide, [73] di(phenothiazinyl)naphthalene, [3b] di(phenothiazinyl)dibenzothiophenes, [74] and three‐component crystals consisting of 5,5′‐(ethyne‐1,2‐diyl)‐bis(2‐pyridin‐3‐yl‐isoindoline‐1,3‐dione), tris(pentafluorophenyl)borane, and simple benzenes [75] . We hope that this article will contribute to the advancement of fluorescence–phosphorescence dual‐emissive materials and their applications.…”

Persistent Room‐Temperature Phosphorescence from Purely Organic Molecules and Multi‐Component Systems

“…reported two groups of ladder‐type organic phosphors ( Figure a). [ 53 ] In group B, they utilized the bulky norbornyl (NB) moiety to separate N ‐methyl phthalimide groups, achieving persistent RTP for which the phosphorescence lifetime can reach 357.1 ms with quantum yields up to a relatively high value of 2% (Figure 4a). By analyzing the crystal structure, they found that a parallel stacking alignment reduces the p – p distances which generate stronger hydrogen to oxygen and p interactions between molecules (Figure 4b).…”

Water‐Induced Blue‐Green Variable Nonconventional Ultralong Room Temperature Phosphorescence from Cross‐Linked Copolymers via Click Chemistry

“…Materials with room temperature phosphorescence (RTP) have shown application prospects in the fields of information encryption, [1][2][3][4][5] dynamic anti-counterfeiting, [6][7][8][9][10] chemical sensing, [11] and biological imaging. [12][13][14] The RTP phenomenon comes from the process that triplet excited states (T 1 ) move back to the reaction procedure.…”