The emission response for vibration-induced emission luminogens is highly sensitive to the encountered steric hindrance during the planarization process such that a tiny structural variation could induce an obvious change in fluorescence.

The development of color-tunable white-light-emitting systems is significant for artificial smart materials. Recently, a set of conformational dependent fluorophores N,N′-diaryl-dihydrodibenzo­[a,c]­phenazines (DPACs) have been developed with unique photoluminescence mechanism vibration-induced emission (VIE). DPACs can emit intrinsical blue emission at a bent excited state and abnormal orange-red emission at a planar excited state, which are due to the varied π-conjugation via excited-state configuration transformation along the N-N′ axis from bent to planar form. Herein, a novel VIE-active compound DPAC-[B15C5]2 is designed and synthesized with two wings of benzo-15-crown-5. The excited-state vibration of the DPAC moiety can be modulated by tuning the supramolecular assembly and disassembly via chelation competition of K+ between 15-crown-5 and 18-crown-6, and hence, a wide-color-tuning emission is achieved from blue to orange-red including white. Dynamic light scattering and transmission electron microscopy experiments were conducted to exhibit the supramolecular assembling process. Additionally, the moisture detection in organic solvents is realized since the water could dissociate the supramolecular assembly.

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...