Tunable Photoluminescence Including White‐Light Emission Based on Noncovalent Interaction‐Locked N,N′‐Disubstituted Dihydrodibenzo[a,c]phenazines

Abstract

design and tedious synthesis of complicated molecules with multiple functional groups, supramolecular assembling has been widely employed as an innovative and efficient method to achieve facile tuning of the photophysical properties. [4] Additionally, supramolecular assembling systems with multiple components connected by reversible noncovalent interactions might also bring out unexpected photoluminescent properties, [5] which is quite appealing for the development of novel optical materials. Numerous strategies to tune the fluorescence emission have been reported in supramolecular assembling systems, including electron transfer or energy transfer among luminophores, [6] the variation of π-π interaction, [7] hydrogen-bonding interaction, [8] and hostguest interaction to influence the assembling structures. [5a,9] For example, Tao and co-workers [10] provided a supramolecular approach to achieve tunable fluorescence emission based on host-guest interaction between cucurbit[8]urial (CB[8]) and a cationic aromatic guest oligo(p-phenylenevinylene) (OPV) derivatives. The rigid hydrophobic cavity of CB[8] host could capture two objective guests, leading to the formation of J-dimer complexes and the broadening of emission wavelength. Moreover, we used supramolecular host molecule γ-cyclodextrin to form host-guest complexes with a two-arm fluorophore and successfully achieved tunable photoluminescence emission, [11] which resulted from host-enhanced intramolecular charge-transfer and host-induced restriction of intramolecular rotation. That postsynthetic modification of supramolecular structures via host-guest interactions has attracted continuous attention and provides a facile strategy for tuning the photophysical properties without a complex chemical synthesis.Phenazine derivatives have been widely investigated for application in organic electronics owing to highly electronrich and redox-active properties, whose structural modification focuses on the benzene rings or the addition of long alkyl chains to the nitrogen atoms for construction of polymers utilized in optical devices. [12] As a novel branch of phenazine Utilizing supramolecular assembling system to achieve tunable photoluminescence emission has become an important method for the development of light-emitting materials, which could bring out intriguing photophysical properties out of the luminophores themselves without a demanding design and tedious chemical synthesis. In the last few years, vibration-induced emission (VIE) molecules, with dual photoluminescence emissions and largeStokes shift, have shown their talent in generating tunable fluorescence and potential in fabricating novel light-emitting materials. However, little attention has been devoted to explore the attractive properties of VIE molecules in supramolecular self-assembling systems up to now. Herein, the first example of a supramolecular assembling system composed of a water-soluble VIE molecule N,N′-diphenyl-dihydrodibenzo[a,c] (0.32, 0.37)) to blue are achieved by simple addition of...

Modulating Room Temperature Phosphorescence by Oxidation of Thianthrene to Achieve Pure Organic Single-Molecule White-Light Emission

“…Generally, two or three radiative excited states are designed to be responsible for simultaneous dual emission (blue and yellow/orange) or ternary emission (blue, green, and red), corresponding to two-color or three-color white-light strategy in SMWLEs, respectively. In the simplest two-color strategy, one excited state is usually the lowest singlet state (S 1 ) for blue fluorescence emission, and the other excited state can be from the charge-transfer state, 4,5 proton-transfer state, [6][7][8] excimer state, 9,10 self-assembly state, [11][12][13][14][15][16] and the lowest triplet state (T 1 ) for room temperature phosphorescence (RTP) [17][18][19][20][21][22] and other methods [23][24][25] for low-energy yellow/orange emission. According to the Chroma Theory, a standard two-color white light requires not only wavelength matching but also intensity matching between two emission spectra, indicating a rather intricate modulation between energy level and photoluminescence (PL) efficiency of two excited states.…”

Fluorescent glycoconjugates and their applications

“…The fluorescence emission of these VIEgens can reversibly shift between the blue and red region when the microenvironment they exist, such as temperature, polarity and viscosity, is changed. [28][29][30][31][32][33][34][35][36][37] The present review will be divided according to the different fluorophores to which carbohydrates are conjugated, producing structurally and functionally diverse fluorescent glycoclusters. Representative examples of polymeric backbones used for building multivalent fluorescent glycoconjugates are also summarized.…”

Manipulating Aggregation‐Induced Emission with Supramolecular Macrocycles

“…Significantly, extensive areas of the relative research also remain in need of in‐depth exploration. For instance, Tian and co‐workers have endeavored in the investigations on the concept of vibration‐induced emission (VIE) and the fabrications of VIE‐molecule containing color‐tunable fluorescent materials based on host–guest chemistry, which would also initiate the appearance for more novel smart photoluminescent materials …”