Restriction Of Intramolecular Motion Research Articles

Ligand Meta-Anchoring Strategy in Metal-Organic Frameworks for Remarkable Promotion of Quantum Yields.

Aggregation is a conventional method to enhance the quantum yields (QYs) of pure organic luminophores due to the restriction of intramolecular motions (RIM). However, how to realize RIM in metal-organic frameworks (MOFs) is still unclear and challenging. In this work, the ligand meta-anchoring strategy is first proposed and proved to be an effective and systematic approach to restrict the intramolecular motions of MOFs for the QY improvement. By simply shifting the substituent position in the ligand from para to meta, the QY of the resulting MOF is significantly enhanced by eleven-fold. The value is even higher than that of ligand aggregates, demonstrating the strong RIM effect of this ligand meta-anchoring strategy. The introduction of co-ligand induces the appearance of visible yellow room temperature phosphorescence with a lifetime of 222 ms due to the QY enhancement and the charge transfer between the donor and accepter units. The present work thus broadens the understanding of the RIM mechanism from a new perspective, develops a novel method to realize RIM and expands the applicable objects from pure organic materials to organic-inorganic hybrid materials.

Ligand Meta‐Anchoring Strategy in Metal‐Organic Frameworks for Remarkable Promotion of Quantum Yields

Aggregation is a conventional method to enhance the quantum yields (QYs) of pure organic luminophores due to the restriction of intramolecular motions (RIM). However, how to realize RIM in metal‐organic frameworks (MOFs) is still unclear and challenging. In this work, the ligand meta‐anchoring strategy is first proposed and proved to be an effective and systematic approach to restrict the intramolecular motions of MOFs for the QY improvement. By simply shifting the substituent position in the ligand from para to meta, the QY of the resulting MOF is significantly enhanced by eleven‐fold. The value is even higher than that of ligand aggregates, demonstrating the strong RIM effect of this ligand meta‐anchoring strategy. The introduction of co‐ligand induces the appearance of visible yellow room temperature phosphorescence with a lifetime of 222 ms due to the QY enhancement and the charge transfer between the donor and accepter units. The present work thus broadens the understanding of the RIM mechanism from a new perspective, develops a novel method to realize RIM and expands the applicable objects from pure organic materials to organic‐inorganic hybrid materials.

Water bridges as the trigger in an amino functionalized Zn-MOF for highly selective and sensitive fluorescent sensing of water

Water is a fundamental element for life. The highly selective and sensitive sensing of water is always attractive for mankind in activities such as physiological processes study and extraterrestrial life exploration. Fluorescent MOFs with precise channels and functional groups might specifically recognize water molecules with hydrogen-bond interaction or coordination effects and work as water sensors. As a proof of concept, herein, an amino functionalized Zn-MOF (named as complex 1) with pores that just right for water molecules to form hydrogen bond bridges is revealed for highly selective and sensitive fluorescent sensing of water. The single-crystal X-ray diffraction analysis indicates that the 3D framework of complex 1 is functionalized with free amino groups in the channels. Hydrogen bonds formed in the channel along b-axis as water bridges to connect two adjacent NH2bdc ligands and result in the restriction of intramolecular motions (RIM) which could responsible for the selective turn-on fluorescence response to water. Complex 1 exhibits high sensitive to trace amount of water in organic solvents and could be used for water detection in a wide range water contents. Take advantages of complex 1, portable sensors (complex 1@PMMA) were prepared and used in the highly sensitive water sensing.

Combined DFT and QM/MM Modeling on Multifunctional TADF Sensitizers and Hot-Exciton Emitters via Carborane Triads for Blue Hyperfluorescent OLEDs.

The scarcity of novel luminogens significantly impedes the advancement of TADF sensitizers and hot exciton emitters, attracting considerable attention for their potential to enhance energy conversion efficiencies in hyperfluorescent OLEDs. In this study, a systematic investigation is employed to design and develop multifunctional materials based on carborane cores through DFT and TD-DFT methods. In pursuit of this objective, 45 carborane triad-type molecules were systematically designed using four donors and two acceptor units. Electronic structure calculations revealed that (i) the singlet, triplet, ΔEST, and SOC values exhibit an increased trend as the carborane core shifts from ortho to meta to para, while an increase in donor strength on the core leads to a decrease in these values. (ii) Moreover, there is a decrease in reorganization energies, absorption wavelengths, ISC, and RISC rates as the carborane switches from ortho to meta to para while witnessing an increase in donor strength. The QM/MM study reveals that para carborane's restricted intramolecular motions improve its solid-state aggregation over ortho carborane and solution phases. Interestingly, carborane triads featuring P-DMB and P-BODIPY acceptor units satisfy the desired criteria for multifunctional TADF sensitizers and hot exciton emitters, respectively.

Loading of AuNCs with AIE effect onto cerium-based MOFs to boost fluorescence for sensitive detection of Hg2+

Ligand-protected gold nanoclusters (AuNCs) have become promising nanomaterials in fluorescence (FL) methods for mercury ions (Hg2+) monitoring, but low FL efficiency hinders their widespread application. Herein, AuNCs/cerium-based metal-organic frameworks (AuNCs/Ce-MOFs) were prepared by loading 6-aza-2-thiothymine-protected AuNCs (ATT-AuNCs) with aggregation-induced emission (AIE) effect on the surface of Ce-MOFs by electrostatic attraction. This strategy improved the FL intensity of AuNCs through two aspects: (i) the AIE effect of ATT-AuNCs and (ii) the confinement effect of Ce-MOFs, which improved the restriction of intramolecular motion (RIM) of ATT-AuNCs. In addition, Ce-MOFs could adsorb and aggregate Hg2+ during detection, which might increase the local concentration. Therefore, based on the high FL signal of AuNCs/Ce-MOFs and enriched Hg2+, sensitive detection of Hg2+ could be achieved. More importantly, the strong specific recognition between AuNCs and Hg2+ could guarantee selectivity. The developed FL sensor exhibited superior detection performances with a wide linear range of 0.2–500 ng mL−1 and a low detection limit of 0.067 ng mL−1. Furthermore, the FL sensor used for sensitive and selective detection of Hg2+ in real samples, and the results agreed well with the standard method. In summary, this work proposed an effective and generalized strategy for improving the FL efficiency of AuNCs, which would greatly facilitate their application in pollutant monitoring.

A Rationally Designed Prodrug for the Fluorogenic Labeling of Albumin and Theranostic Effects on Drug-Induced Liver Injury.

The development of small-molecular fluorogenic tools for the chemo-selective labeling of proteins in live cells is important for the evaluation of intracellular redox homeostasis. Dynamic imaging of human serum albumin (HSA), an antioxidant protein under oxidative stress with concomitant release of antioxidant drugs to maintain redox homeostasis, affords potential opportunities for disease diagnosis and treatment. In this work, we developed a nonfluorogenic prodrug named TPA-NAC, by introducing N-acetyl-l-cysteine (NAC) into a conjugated acceptor skeleton. Through combined thiol and amino addition, coupling with HSA results in fluorescence turn-on and drug release. It was reasoned that the restricted intramolecular motion of the probe under an HSA microenvironment after covalent bonding inhibited the nonradiative transitions. Furthermore, the biocompatibility and photochemical properties of TPA-NAC enabled it to image exogenous and endogenous HSA in living cells in a wash-free manner. Additionally, the released drug evoked upregulation of superoxide dismutase (SOD), which synergistically eliminated reactive oxygen species in a drug-induced liver injury model. This study provides insights into the design of new theranostic fluorescent prodrugs for chemo-selective protein labeling and disease treatments.

Two novel chiral AIEgens as coordination precursors: synthesis, structures and photophysical study

Two novel chiral molecules, (4S)-5,5-dimethyl-2-(4-oxo-4H-chromen-3-yl)thiazolidine-4-carboxylic acid (OCCA) and (4S)-5,5-dimethyl-2-(4-(1,2,2-triphenylvinyl)phenyl)thiazolidine-4-carboxylic acid (TPCA), were successfully synthesized by aldehyde amine condensation reaction, and their structures were characterized by 1H NMR and single crystal X-ray diffraction. The intensities of photoluminescence changed with the aggregation, exhibiting that OCCA and TPCA are aggregation-induced emission luminogens (AIEgens). After complete aggregation, OCCA emitted the purple-blue light at the peak of 388 nm and TPCA emitted the cyan light at the peak of 488 nm. The aggregation-induced emission (AIE) effects for OCCA and TPCA resulted from local state to twisted intermolecular charge transfer (TICT) and restriction of intramolecular motion (RIM), respectively. Other spectra including UV–vis, IR, and Raman spectra were also discussed in detail.

Aminoguanidine-based bioactive proligand as AIEE probe for anticancer and anticovid studies.

The emission features of a novel bioactive compound, 1,3-bis(2-hydroxy-3,5-diiodophenyl-methylideneamino)guanidine is found impressive with aggregation induced emission enhancement. The nitrogen and iodine rich multidentate proligand was characterized physicochemically. SCXRD and Hirshfeld surface investigation have revealed the presence of significant triangular iodine bonding apart from hydrogen bonding, weak C-H⋯π and π⋯π intermolecular interactions. These interactions collectively contribute to the solid-state packing arrangement of the molecules within the crystal lattice. The band gap of the compound was estimated experimentally and is supported with theoretical calculations. The solid-state fluorescence quantum yield of Φ = 0.36 emphasizes the utility of the proligand and the AIEE characteristics is attributed to restricted intramolecular motions as indicated by fluorescence lifetime decay studies. Strong interaction of the compound with calf thymus DNA was explored experimentally and found to align with in silico docking results. Notably, in vitro anticancer assessment on MCF-7 breast cancer cells show an IC50 value of 181.05 μg mL-1 and signifying its potent cytotoxic properties. Also, the compound is found to have lesser cytotoxicity against L929 normal cell line with an IC50 value of 356.54 μg mL-1. Computational studies further underscore the exceptional binding affinity with active sites in the SARS-CoV-2 main protease 3CLpro, surpassing established repurposed drugs. Furthermore, the proligand demonstrates excellent putative affinity towards the SARS-CoV-2 spike glycoprotein, accompanied by its distinctive AIEE attributes, drug likeness and DNA binding capability rendering it a valuable tool for prospective research investigations.

Polystyrene‐Based Matrix to Enhance the Fluorescence of Aggregation‐Induced Emission Luminogen for Fluorescence‐Guided Surgery

AbstractAchieving ultrabright fluorogens is a key issue for fluorescence‐guided surgery (FGS). Fluorogens with aggregation‐induced emission (AIEgens) are potential agents for FGS on the benefit of the bright fluorescence in physiological conditions. Herein, the fluorescence brightness of AIEgen is further improved by preparing the nanoparticle using a polystyrene‐based matrix and utilizing it for tumor FGS with a high signal‐to‐background ratio. After encapsulating AIEgen into polystyrene‐poly (ethylene glycol) (PS‐PEG), the fluorescence intensity of the prepared AIE@PS‐PEG nanoparticles is multiple times that of nanoparticles in 1, 2‐distearoyl‐sn‐glycero‐3‐phosphoethanolamine‐poly (ethylene glycol) (DSPE‐PEG), a commonly used polymer matrix for nanoparticle preparation. Molecular dynamics simulations suggest that higher free energy is required for the outer rings of AIEgen to rotate in polystyrene than in the DSPE, indicating that the benzene rings in polystyrene can restrict the intramolecular motions of AIEgen better than the alkyl chain in DSPE‐PEG. Fluorescence correlation microscopy detections suggest that the triplet excited state of AIEgens is less in PS‐PEG than in DSPE‐PEG. The restricted intramolecular motions and suppressed triplet excited state result in ultrabright AIE@PS‐PEG nanoparticles, which are more conducive to illuminating tumor tissues in the intestine for FGS. The illumination of metastatic tumors in lungs by AIE@PS‐PEG nanoparticles is also tried.

A triphenylamine-based near-infrared fluorescence turn off probe for nitroreductase imaging

Nitroreductase (NTR) is an essential biomarker for various diseases and widely used to evaluate the hypoxia status in tumor cells. In this work, we developed a near-infrared (NIR) fluorescence “on-off” probe PTP based on a triphenylamine scaffold, with an intrinsic long wavelength emission more than 700 nm. This probe showed typical aggregation-induced emission (AIE) properties with the increase of PBS fraction (fw), which might be attributed to the restriction of intramolecular motions (RIM) effect in high aqueous solution. The frontiers molecular orbitals (FMO) of the probe PTP and the resulting reduction compounds (PT-OH and TPA-OH) were calculated to determine their structure differences. The two nitro groups were reduced in response to NTR and then released the substance TPA-OH through the 1,6-rearrangement-elimination, resulting in simultaneous fluorescence decrease. This process was also demonstrated by the DFT/TD-DFT and docking calculations, indicating a favorable structural and spatial match between the probe and NTR. More importantly, the probe was successfully used to visualize the NTR distribution in living A431 cells with nontoxicity. It exhibited a time-dependent fluorescence quenching behavior at the cellular level, making it of great potential in NTR detection for other biosystems.

Synergistically Boosting the Circularly Polarized Luminescence of Functionalized Pillar[5]arenes by Polymerization and Aggregation.

Supramolecular polymers based on chiral macrocycles have attracted increasing attention in the field of circularly polarized luminescence (CPL) owing to their unique properties. However, the construction of macrocyclic supramolecular polymers with highly efficient CPL properties in aggregate states still remains challenging. Herein, w e constructed a class of macrocycle-based coordination polymers by combining the planar chiral properties of pillar[5]arene with the excellent fluorescence properties of aggregation-induced emission luminogens. The formation of polymers enhances both the fluorescence and chiral properties, resulting in chiral supramolecular polymers with remarkable CPL properties. Increasing the aggregation degree of the polymers can further improve their CPL properties, as evidenced by a 21-fold increase in the dissymmetry factor and an over 25-fold increase in the fluorescence quantum yield in the aggregate state compared to the solution state. Such a synergistic effect of polymerization- and aggregation-enhanced CPL can be explained by the restriction of intramolecular motions and aggregation-induced conformation confinement. This work provides a promising method for developing highly efficient CPL supramolecular polymers.

Aggregation-Induced Enhanced Electrochemiluminescence from Tris(bipyridine)ruthenium(II) Derivative Nanosheets for the Ultrasensitive Detection of Human Telomerase RNA.

The traditional tris(bipyridine)ruthenium(II) complex suffers from the notorious aggregation-caused quenching effect, which greatly compromises its electrochemiluminescence (ECL) efficiency, thus hindering further applications in biosensing and clinical diagnosis. Here, the ultrathin tetraphenylethylene-active tris(bipyridine)ruthenium(II) derivative nanosheets (abbreviated as Ru-TPE NSs) are synthesized through a protein-assisted self-assembly strategy for ultrasensitive ECL detection of human telomerase RNA (hTR) for the first time. The synthesized Ru-TPE NSs exhibit the aggregation-induced enhanced ECL behavior and excellent water-dispersion. Surprisingly, up to a 106.5-fold increase in the ECL efficiency of Ru-TPE NSs is demonstrated compared with the dispersed molecules in an organic solution. The restriction of intramolecular motions is confirmed to be responsible for the significant ECL enhancement. Therefore, this proposed ECL biosensor shows high sensitivity and excellent selectivity for hTR based on Ru-TPE NSs as efficient ECL beacons and the catalytic hairpin assembly as signal amplification, whose detection limit is as low as 8.0fm, which is far superior to the previously reported works. Here, a promising analytical method is provided for early clinical diagnosis and a new type of efficient ECL emitters with great application prospects is represented.

Triphenylamine-Based N,O-Bidentate BF2 -Enolimine Initiator for Three-Arm Star Polymethacrylates with Dual-State Fluorescent Emission.

Three-arm star polymethacrylates with dual-phase (solution and solid-state) fluorescent emission have been synthesized via atom transfer radical polymerization (ATRP) using a triphenylamine-derived organboron complex (TAPA-BKI-3Br) as initiator. The as-synthesized three-arm star polymethacrylates exhibited bright emission in both solution and the solid states due to the highly twisted structure and intramolecular charge transfer (ICT) effect of TAPA-BKI core, as well as the steric effect and restriction of intramolecular motions from the polymer arms. And the polymer chains have an important influence on the photophysical behavior of the as-synthesized three-arm star polymethacrylates in the aggregated state.

Exploration of Water-Soluble Natural AIEgens Boosting Label-Free Turn-on Fluorescent Sensing in a DNA Hydrogel.

Various aggregation-induced emission luminogens (AIEgens) have been developed and applied in different areas in recent years. However, AIEgens generally can aggregate and emit strong fluorescence in aqueous solution even containing DNA and other biomacromolecules because of poor water solubility, restricting their application in biosensing and bioimaging in aqueous solution. Moreover, the great majority of AIEgens commonly suffer from complex organic synthesis, environmental damage, and biological toxicity. In this work, jatrorrhizine (Jat), an isoquinoline alkaloid from Chinese herbs, was found to be a natural water-soluble AIEgen that has not been previously reported. Jat's photometric characteristics and single-crystal structure demonstrated that the restriction of intramolecular motion and twisted intramolecular charge transfer were responsible for its AIE phenomenon. Due to the good water solubility and AIE character of Jat, it did not emit fluorescence in the aqueous solution containing DNA and polymers until the formation of the DNA hydrogel. Therefore, a DNA hydrogel fluorescence biosensor was designed by using the target (miRNA) as a catalyst to trigger the entropy-driven circuit of DNA, realizing the ultrasensitive and label-free detection of miRNA with an ultralow limit of detection (0.049 fM, S/N = 3). This biosensing strategy also has excellent stability and acceptable reliability for real sample assay. The results not only indicated the excellent sensing performance of Jat as AIE probes in aqueous solution but also demonstrated the promising application potential of water-soluble natural AIEgens.

A novel nitroreductase-responsive turn-off fluorescent probe based on AIEgen and its bioimaging application

Nitroreductase (NTR) is frequently employed as a biomarker to assess the level of hypoxia in tumor tissues. To date, the majority of NTR-reactive probes have focused on the luminescence "turn on" characteristic, which has been plagued by background interferences. In this study, we present the first report of an NTR-responsive "turn-off" fluorescent probe, TPEDCH-PBN, based on AIEgen. This probe exhibits typical aggregation-induced emission (AIE) properties in high PBS fraction, which may be attributed to the restriction of intramolecular motions (RIM) effect. DFT/TD-DFT calculations were employed to determine the discrepancies in structure and electron density distribution among TPEDCH, TPEDCH-PBNOH and TPEDCH-PBN. Additionally, docking calculations were utilized to elucidate the structure-function relationship between the probe and NTR, revealing a favorable structural and spatial match. Photophysical investigations demonstrated the probe's high selectivity towards NTR with the detection limit of 0.68 μg/mL. The dynamic quenching process of TPEDCH-PBN upon NTR was examined, and the quenching constant Ksv was determined to be 53.6 g−1.L. In addition, the NTR detection ability of probe TPEDCH-PBN as well as its time-dependent fluorescence quenching behaviors were confirmed by cell imaging of probe in A549 cells. Overall, this study proposed a novel molecular design approach for the biomarker detection probe, which may prove to be more extensively applicable.

Hexaphenyl-butadiene derivative with aggregation-induced emission characteristic for high-sensitive detection of ursolic acid, oleanolic acid, and glycyrrhizic acid

Plant natural products (PNPs) have a wide range of pharmacological effects and biological activities, including antitumor, antiinflammatory, antibacterial, and antiviral properties. These properties can be beneficial for their use in the health care industry. As representative PNPs, ursolic acid (UA), oleanolic acid (OA), and glycyrrhizic acid (GA) have been efficiently biosynthesized in microbial cells. In this study, hexaphenyl-butadiene methylpyridine salt (HPB-I) with an aggregation-induced emission characteristic (AIE) was developed as a simple, real-time, and efficient quantitative probe for detection of PNPs. Experimental results showed that HPB-I has a highly selective fluorescence response to UA, OA, and GA among 18 PNPs. Three detection methods were employed. Dilution of a PNP aqueous solution with dimethyl sulfoxide was optimal with low limits of detection of 0.16 (UA), 0.23 (OA), and 0.066 (GA) nmol/mL. Scanning electron microscopy, dynamic light scattering, and zeta potential analyses revealed that the PNPs were effectively adsorbed on the surface of HPB-I aggregates, which resulted in an increase in the fluorescence response based on restriction of intramolecular motion. HPB-I could also effectively and quantitatively detect the three PNPs in a synthetic dropout (SD) culture medium. This study provides a valuable approach toward the development of a real-time low-cost method for in-situ PNP detection of biosynthesis processes in microbial cells.

Understanding H-aggregates crystallization induced emissive behavior: insights from theory

We conducted a theoretical investigation into how the molecular stacking effect impacts the photophysical properties in solid phases. Our findings indicated that in the aggregated state, the out-of-plane distorted vibration and imidazole ring stretching vibration of triimidazo-[1,3,5] triazinethe are significantly suppressed, which decreased the Huang-Rhys factor and the corresponding reorganization energy of the photophysical process, as a result, this restricted intramolecular motions and dissipation pathways of excess energy in the excited state, therefore, aggregation induced enhancement emission (AIEE) was found for the title compound from dichloromethane solution to solid state. Analysis of the emission spectrum through discrete spectral lines revealed that the main peak was affected by the vibrational modes with lower frequencies, while the middle-frequency modes influenced the shoulder peak. Furthermore, the predicted intersystem crossing rate (kiosk) and reverse intersystem crossing rate (krisc) using Marcus theory confirmed that an electron can successfully shift from its S1 state to the T1 state, however, the reverse T1 → S1 process can not come into being due to very small krisc (10–6–10–9 s–1), therefore the phosphorescence can be observed. At last, we explored the influence of charge transfer process of the title compound, our theoretical data declared this process can be ignored due to its low transfer rate.

Emission or scattering? Discriminating the origin of responsiveness in AIEgen‐doped smart polymers using the TPE dye

AbstractAggregation‐induced emission (AIE) luminogens are attractive dyes to probe polymer properties that depend on changes in chain mobility and free volume. When embedded in polymers the restriction of intramolecular motion (RIM) can lead to their photoluminescence quantum yield (PLQY) strong enhancement if local microviscosity increases (lowering of chain mobility and free volume). Nonetheless, measuring PLQY during stimuli, i.e. heat or mechanical stress, is technically challenging; thus, emission intensity is commonly used instead, assuming its direct correlation with the PLQY. Here, by using fluorescence lifetime as an absolute fluorescence parameter, it is demonstrated that this assumption can be invalid in many commonly encountered conditions. To this aim, different polymers are loaded with tetraphenylenethylene (TPE) and characterized during the application of thermal and mechanical stress and physical aging. Under these conditions, polymer matrix transparency variation is observed, possibly due to local changes in refractive index and to the formation of microfractures. By combining different characterization techniques, it is proved that scattering can affect the apparent emission intensity, while lifetime measurements can be used to ascertain whether the observed phenomenon is due to modifications of the photophysical properties of AIE dyes (RIM effect) or to alterations in the matrix optical properties.

Dehydroabietic acid and triphenylamine combined BioAIEgens with an imine linker and RIM: mechanochromism and acidichromism

The petrochemical-based multi-stimuli responsive materials have been widely explored as advanced functional materials in the past several decades, but they inevitably face problems like complicated synthesis, non-renewability, and non-sustainability. On this basis, the bio-based materials used to construct multi-stimuli responsive due to the unique natural structures have come to the fore. In this work, three novel triphenylamine-based salicylideneanilines have been simply designed with aggregation-induced emission (AIE) properties. Among all, DAMB-TPAOH and DAMB-TPA possessing the natural structure of dehydroabietic acid from rosin are bioproduct-inspired AIE luminogens (BioAIEgens). Derived from the excited-state intramolecular proton transfer (ESIPT) and restriction of intramolecular motion (RIM) dual-mechanism caused by the hydroxyl group and rigidification of alicyclic moiety, respectively, the solid-state DAMB-TPAOH exhibits red-shifted (compared to DAMB-TPA) and stronger (compared to BA-TPAOH) emission, endowing this BioAIEgen with the best fluorescence behavior. Further, the introduction of the natural skeleton, propeller TPA, and imine group results in the high-contrast mechanochromic and acidichromic properties of DAMB-TPAOH. The multi-stimuli responsive properties endow DAMB-TPAOH with potential utilization in the manufacture of rewritable paper and multi-color ink. The current work contributes greatly to the development of BioAIEgens with both mechanochromism and acidichromism.

Novel 4,4′-Binaphthalimidyl derivatives with carboxyalkyl side chains: Synthesis, Aggregation-induced emission, Hydrogel and Cell imaging

The introduction of aryl groups and/or alkyl side chains to the periphery of a conjugated skeleton can modulate the pattern of molecular aggregation in solution and facilitate its aggregation-induced emission (AIE) performance. In this study, novel three compounds of 4,4′-binaphthalimidyl derivatives (BNICn) were synthesized successfully in which two 1,8-naphthalimide (NI) units were connected by a rotatable single bond at their 4-sites, and two carboxyalkyl chains (number of carbon atoms in the carboxyalkyl chains (n) = 2, 6, and 11) were linked with the nitrogen atoms of NI. BNICn has weakly fluorescent in dilute solutions but become highly emissive in aggregate states. Interestingly, they exhibited carboxyalkyl-dependent AIE properties. The AIE performance of BNIC2 with the shortest carboxyalkyl chain is the strongest among those of the three compounds. The aggregation was also confirmed by the dynamic light scattering (DLS) tests. Moreover, the fluorescence intensities enhanced with the increasing viscosity of the solutions, verifying that the restriction of intramolecular motions (RIM) leads to the occurrence of AIE. Furthermore, the interactions such as π-π stacking of NI groups, and the intermolecular hydrogen-bonding of the carboxyl groups at the terminal of the side chains of BNICn was respectively verified by 1H NMR and FTIR. Thus, a possible self-assemble mode of BNICn is that the stacking NI segments of BNICn are located by the intermolecular hydrogen bonds of carboxyl groups at the terminal of the side chains of BNICn enacting an anchor-like role during aggregation process. For BNIC2 with carboxymethyl group, the shortest spacer of methylene group resulted in more effectively restriction for the intramolecular vibration and rotation, leading to a more efficient AIE performance. Meanwhile, BNIC11 can form thermal-reversible fluorescence hydrogel with ethylenediamine as well as BNIC2 can be applied in cellular imaging. Thus, an effective strategy to achieve and adjust the AIE performance of NI derivatives is proposed.