Molecules

Research

13 pages, 4233 KiB

Open AccessArticle

Crystallization-Enhanced Emission and Room-Temperature Phosphorescence of Cyclic Triimidazole-Monohexyl Thiophene Derivatives

by Daniele Malpicci, Alessandra Forni, Elena Cariati, Riku Inoguchi, Daniele Marinotto, Daniele Maver, Federico Turco and Elena Lucenti

Molecules 2023, 28(1), 140; https://doi.org/10.3390/molecules28010140 - 24 Dec 2022

Cited by 2 | Viewed by 1885

Abstract

The development of organic room-temperature phosphorescent (ORTP) materials represents an active field of research due to their significant advantages with respect to their organometallic counterparts. Two cyclic triimidazole (TT) derivatives bearing one and three hexyl-thiophene moieties, TT-HThio and TT-(HThio)₃, [...] Read more.

The development of organic room-temperature phosphorescent (ORTP) materials represents an active field of research due to their significant advantages with respect to their organometallic counterparts. Two cyclic triimidazole (TT) derivatives bearing one and three hexyl-thiophene moieties, TT-HThio and TT-(HThio)₃, have been prepared and characterized. Both compounds display enhanced quantum yields in their crystalline form with respect to those in a solution state, revealing crystallization-enhanced emissive (CEE) behavior. Importantly, while single fluorescence is observed in solution, crystalline powders also feature dual ORTP, whose respective molecular and aggregate origins have been disclosed through X-ray diffraction analysis and DFT/TDDFT calculations. The relation between the photophysical properties of TT-HThio and its crystallinity degree has been confirmed by a decrease in photoluminescent quantum yield (Φ) and loss of vibronic resolution when its crystals are ground in a mortar, revealing mechanochromic behavior and confirming CEE features. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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12 pages, 2068 KiB

Open AccessArticle

Copolymers of 4-Trimethylsilyl Diphenyl Acetylene and 1-Trimethylsilyl-1-Propyne: Polymer Synthesis and Luminescent Property Adjustment

by Tanxiao Shen, Manyu Chen, Haoke Zhang, Jing Zhi Sun and Ben Zhong Tang

Molecules 2023, 28(1), 27; https://doi.org/10.3390/molecules28010027 - 21 Dec 2022

Cited by 10 | Viewed by 1702

Abstract

Poly(4-trimethylsilyl diphenyl acetylene) (PTMSDPA) has strong fluorescence emission, but its application is limited by the effect of aggregation-caused quenching (ACQ). Copolymerization is a commonly used method to adjust the properties of polymers. Through the copolymerization of 4-trimethylsilyl diphenyl acetylene and 1-trimethylsilyl-1-propyne (TMSP), we [...] Read more.

Poly(4-trimethylsilyl diphenyl acetylene) (PTMSDPA) has strong fluorescence emission, but its application is limited by the effect of aggregation-caused quenching (ACQ). Copolymerization is a commonly used method to adjust the properties of polymers. Through the copolymerization of 4-trimethylsilyl diphenyl acetylene and 1-trimethylsilyl-1-propyne (TMSP), we successfully realized the conversion of PTMSDPA from ACQ to aggregation-induced emission (AIE) and aggregation-induced emission enhancement (AEE). By controlling the monomer feeding ratio and with the increase of the content of TMSDPA inserted into the copolymer, the emission peak was red-shifted, and a series of copolymers of poly(TMSDPA-co-TMSP) that emit blue–purple to orange–red light was obtained, and the feasibility of the application in explosive detection was verified. With picric acid (PA) as a model explosive, a super-quenching process has been observed, and the quenching constant (K_SV) calculated from the Stern–Volmer equation is 24,000 M⁻¹, which means that the polymer is potentially used for explosive detection. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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27 pages, 7586 KiB

Open AccessArticle

Tailoring the AIE Chromogen 2-(2-Hydroxyphenyl)benzothiazole for Use in Enzyme-Triggered Molecular Brachytherapy

by Zhiyuan Wu, Jinghuai Dou, Kathy-Uyen Nguyen, Jayden C. Eppley, Kittipan Siwawannapong, Yunlong Zhang and Jonathan S. Lindsey

Molecules 2022, 27(24), 8682; https://doi.org/10.3390/molecules27248682 - 8 Dec 2022

Cited by 3 | Viewed by 2270

Abstract

A targeted strategy for treating cancer is antibody-directed enzyme prodrug therapy, where the enzyme attached to the antibody causes conversion of an inactive small-molecule prodrug into an active drug. A limitation may be the diffusion of the active drug away from the antibody [...] Read more.

A targeted strategy for treating cancer is antibody-directed enzyme prodrug therapy, where the enzyme attached to the antibody causes conversion of an inactive small-molecule prodrug into an active drug. A limitation may be the diffusion of the active drug away from the antibody target site. A related strategy with radiotherapeutics entails enzymatically promoted conversion of a soluble to insoluble radiotherapeutic agent, thereby immobilizing the latter at the target site. Such a molecular brachytherapy has been scarcely investigated. In distinct research, the advent of molecular designs for aggregation-induced emission (AIE) suggests translational use in molecular brachytherapy. Here, several 2-(2-hydroxyphenyl)benzothiazole substrates that readily aggregate in aqueous solution (and afford AIE) were elaborated in this regard. In particular, (1) the 2-(2-hydroxyphenyl) unit was derivatized to bear a pegylated phosphodiester that imparts water solubility yet undergoes enzymatic cleavage, and (2) a p-phenol unit was attached to the benzo moiety to provide a reactive site for final-step iodination (here examined with natural abundance iodide). The pegylated phosphodiester-iodinated benzothiazole undergoes conversion from aqueous-soluble to aqueous-insoluble upon treatment with a phosphatase or phosphodiesterase. The aggregation is essential to molecular brachytherapy, whereas the induced emission of AIE is not essential but provides a convenient basis for research development. Altogether, 21 compounds were synthesized (18 new, 3 known via new routes). Taken together, blending biomedical strategies of enzyme prodrug therapy with materials chemistry concerning substances that undergo AIE may comprise a step forward on the long road toward molecular brachytherapy. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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9 pages, 1887 KiB

Open AccessArticle

Tricyano-Methylene-Pyridine Based High-Performance Aggregation-Induced Emission Photosensitizer for Imaging and Photodynamic Therapy

by Xupeng Wu, Zhirong Zhu, Zhenxing Liu, Xiangyu Li, Tijian Zhou, Xiaolei Zhao, Yuwei Wang, Yiqi Shi, Qianqian Yu, Wei-Hong Zhu and Qi Wang

Molecules 2022, 27(22), 7981; https://doi.org/10.3390/molecules27227981 - 17 Nov 2022

Cited by 5 | Viewed by 2153

Abstract

Photosensitizers equipped with high reactive oxygen species (ROS) generation capability and bright emission are essential for accurate tumor imaging and precise photodynamic therapy (PDT). However, traditional aggregation-caused quenching (ACQ) photosensitizers cannot simultaneously produce desirable ROS and bright fluorescence, resulting in poor image-guided therapy [...] Read more.

Photosensitizers equipped with high reactive oxygen species (ROS) generation capability and bright emission are essential for accurate tumor imaging and precise photodynamic therapy (PDT). However, traditional aggregation-caused quenching (ACQ) photosensitizers cannot simultaneously produce desirable ROS and bright fluorescence, resulting in poor image-guided therapy effect. Herein, we report an aggregation-induced emission (AIE) photosensitizer TCM-Ph with a strong donor–π–acceptor (D–π–A) structure, which greatly separates the HOMO–LUMO distribution and reduces the ΔE_ST, thereby increasing the number of triplet excitons and producing more ROS. The AIE photosensitizer TCM-Ph has bright near-infrared emission, as well as a higher ROS generation capacity than the commercial photosensitizers Bengal Rose (RB) and Chlorine e6 (Ce6), and can effectively eliminate cancer cells under image guidance. Therefore, the AIE photosensitizer TCM-Ph has great potential to replace the commercial photosensitizers. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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11 pages, 4029 KiB

Open AccessArticle

AIEgen-Enabled Multicolor Visualization for the Formation of Supramolecular Polymer Networks

by Shaoyu Xu, Hanwei Zhang, Qingyun Li, Hui Liu and Xiaofan Ji

Molecules 2022, 27(22), 7881; https://doi.org/10.3390/molecules27227881 - 15 Nov 2022

Cited by 4 | Viewed by 1957

Abstract

Extensive reports on the use of supramolecular polymer networks (SPNs) in self-healing materials, controlled release system and degradable products have led more researchers to tap their potential owing to the unique properties. Yet, the attendant efforts in the visualization through conventional luminescence methods [...] Read more.

Extensive reports on the use of supramolecular polymer networks (SPNs) in self-healing materials, controlled release system and degradable products have led more researchers to tap their potential owing to the unique properties. Yet, the attendant efforts in the visualization through conventional luminescence methods during the formation of SPNs have been met with limited success. Herein, we designed a special type of SPNs prepared by PPMU polymer chains containing pyrene benzohydrazonate (PBHZ) molecules as AIEgens for the multicolor visualization with naked eyes. The complete detection of the formation process of the networks relied on the PBHZ molecules with aggregation-induced ratiometric emission (AIRE) effect, which enabled the fluorescence of the polymer networks transits from blue to cyan, and then to green with the increasing crosslinking degree derived from the hydrogen bonds between 2-ureido-4-pyrimidone (UPy) units of the polymer chains. Additionally, we certificated the stimuli-responsiveness of the obtained SPNs, and the fluorescence change, as well as observing the morphology transition. The AIEgen-enabled multicolor visualization of the formation of SPNs may provide better understanding of the details of the crosslinking interactions in the microstructural evolution, giving more inspiration for the multifunctional products based on SPNs. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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13 pages, 4500 KiB

Open AccessArticle

Development of an HPV Genotype Detection Platform Based on Aggregation-Induced Emission (AIE) and Flow-Through Hybridization Technologies

by Chun-Ho (Charlie) Ma, Liejun Li, Shuheng Cai, Pei Lin, Wing-Ki (Kristy) Lam, Tsz-Him (Ronald) Lee, Tsz-Kin (Ryan) Kwok, Longxu Xie, Tit-Sang (Tom) Kun and Ben-Zhong Tang

Molecules 2022, 27(20), 7036; https://doi.org/10.3390/molecules27207036 - 18 Oct 2022

Cited by 3 | Viewed by 2319

Abstract

Genetic mutations can cause life-threatening diseases such as cancers and sickle cell anemia. Gene detection is thus of importance for disease-risk prediction or early diagnosis and treatment. Apart from genetic defects, gene detection techniques can also be applied to gene-related diseases with high [...] Read more.

Genetic mutations can cause life-threatening diseases such as cancers and sickle cell anemia. Gene detection is thus of importance for disease-risk prediction or early diagnosis and treatment. Apart from genetic defects, gene detection techniques can also be applied to gene-related diseases with high risk to human health such as human papillomavirus (HPV) infection. HPV infection has been strongly linked to cervical cancer. To achieve a high-throughput HPV gene detection platform, the flow-through hybridization system appears to be one of the commercialized diagnostic techniques for this purpose. The flow-through hybridization technique is based on a vacuum-guided flow of DNA fragments which is continuously directed toward the oligoprobes that are immobilized on the testing membrane. However, the conventional colorimetric method and signal read-out approach suffers a problem of low sensitivity. On the contrary, fluorescence approaches allow more sensitive detection and broad sensing ranges. In this work, a fluorescent dye HCAP, which possesses aggregation-induced emission (AIE) properties and is responsive to alkaline phosphatase, was developed and applied to the flow-through hybridization platform to achieve HPV genome diagnosis of clinical samples. Also, an automatic membrane reader was constructed based on the AIE-based diagnosis platform which can identify the diagnostic result of patient DNA with a total concordance rate of 100% in the clinical trial. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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16 pages, 7621 KiB

Open AccessArticle

Development of Yellow-to-Orange Photoluminescence Molecules Based on Alterations in the Donor Units of Fluorinated Tolanes

by Shigeyuki Yamada, Kazuki Kobayashi and Tsutomu Konno

Molecules 2022, 27(18), 5782; https://doi.org/10.3390/molecules27185782 - 7 Sep 2022

Cited by 7 | Viewed by 2117

Abstract

Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) [...] Read more.

Since the aggregation-induced emission (AIE) phenomenon was first reported by Tang et al., much effort has been devoted to the development of solid-state luminescent molecules by chemists worldwide. Our group successfully developed fluorinated tolanes as novel compact π-conjugated luminophores with blue photoluminescence (PL) in the crystalline state. Moreover, we reported the yellow-green PL molecules based on their electron-density distributions. In the present study, we designed and synthesized fluorinated tolanes with various amine-based donors and evaluated their photophysical properties. The carbazole-substituted fluorinated tolane exhibited strong PL in the solution state, whereas piperidine- or phenothiazine-substituted fluorinated tolanes showed a dramatic decrease in PL efficiency. Notably, fluorinated tolanes with piperidine or phenothiazine substituents displayed yellow-to-orange PL in the crystalline state; this may have occurred because these tolanes exhibited tightly packed structures formed by intermolecular interactions, such as H···F hydrogen bonds, which suppressed the non-radiative deactivation process. Moreover, fluorinated tolanes with amine-based donors exhibited AIE characteristics. We believe that these yellow-to-orange solid PL molecules can contribute to the development of new solid luminescent materials. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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12 pages, 3933 KiB

Open AccessArticle

Three-Color White Photoluminescence Emission Using Perovskite Nanoplatelets and Organic Emitter

by Hyukmin Kwon, Sunwoo Park, Seokwoo Kang, Hayoon Lee and Jongwook Park

Molecules 2022, 27(13), 3982; https://doi.org/10.3390/molecules27133982 - 21 Jun 2022

Cited by 2 | Viewed by 2088

Abstract

Three organic blue-light-emitting tetraphenylethylene (TPE) derivatives that exhibit aggregation-induced emission (AIE) were used as additives in the preparation of inorganic perovskite-structured green-light-emitting materials for three-color white-light emission. For these organic–inorganic light-emitting materials, two-color (blue and green) light-emitting films based on the CsPbBr₃ [...] Read more.

Three organic blue-light-emitting tetraphenylethylene (TPE) derivatives that exhibit aggregation-induced emission (AIE) were used as additives in the preparation of inorganic perovskite-structured green-light-emitting materials for three-color white-light emission. For these organic–inorganic light-emitting materials, two-color (blue and green) light-emitting films based on the CsPbBr₃ perovskite-structured green-light-emitting inorganic material were prepared. The three TPE derivatives were prepared by varying the number of bromide groups, and a distinct AIE effect was confirmed when the derivatives were dissolved in a water–tetrahydrofuran mixed solvent containing 90 vol% water. When 0.2 molar ratio of the 1,1,2,2-tetrakis(4-bromophenyl)ethylene (TeBrTPE) additive was mixed with nanocrystal-pinning toluene solvent, the green-light-emission photoluminescence quantum efficiency (PLQY) value at 535 nm was 47 times greater than that of the pure bulk CsPbBr₃ without additives and a blue emission at 475 nm was observed from the TeBrTPE itself. When a CBP:Ir(piq)₃ film was prepared on top of this layer, three PL peaks with maximum wavelength values of 470, 535, and 613 nm were confirmed. The film exhibited white-light emission with CIE color coordinates of (0.25, 0.36). Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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10 pages, 1471 KiB

Open AccessArticle

Modulation of Properties by Ion Changing Based on Luminescent Ionic Salts Consisting of Spirobi(boron ketoiminate)

by Kazumasa Suenaga, Shunichiro Ito, Kazuo Tanaka and Yoshiki Chujo

Molecules 2022, 27(11), 3438; https://doi.org/10.3390/molecules27113438 - 26 May 2022

Cited by 4 | Viewed by 1846

Abstract

We report development of luminescent ionic salts consisting of the boron ketoiminate structure, which is one of the robust skeletons for expressing aggregation-induced emission (AIE) properties. From the formation of the boron-centered spiro structure with the ketoiminate ligands, we obtained stable ionic salts [...] Read more.

We report development of luminescent ionic salts consisting of the boron ketoiminate structure, which is one of the robust skeletons for expressing aggregation-induced emission (AIE) properties. From the formation of the boron-centered spiro structure with the ketoiminate ligands, we obtained stable ionic salts with variable anions. Since the ionic salts show T_ms below 100 °C, it was shown that these salts can be classified as an ionic liquid. By using PF₆ anion, the single crystal—which is applicable for X-ray crystallography—was obtained. According to the optical measurements, it was proposed that electronic interaction should occur through the boron center. Moreover, intense emission was observed both in solution and solid. Finally, we demonstrated that the emission color of the PF₆ salt was altered from crystal to amorphous by adding mechanical forces. Based on boron complexation and intrinsic solid-state luminescent characters, we achieved obtainment of emissive ionic materials with environmental responsivity. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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11 pages, 1829 KiB

Open AccessArticle

Covalent Attachment of Aggregation-Induced Emission Molecules to the Surface of Ultrasmall Gold Nanoparticles to Enhance Cell Penetration

by Kai Klein, Matthias Hayduk, Sebastian Kollenda, Marco Schmiedtchen, Jens Voskuhl and Matthias Epple

Molecules 2022, 27(6), 1788; https://doi.org/10.3390/molecules27061788 - 9 Mar 2022

Cited by 5 | Viewed by 2689

Abstract

Three different alkyne-terminated aggregation-induced emission molecules based on a para-substituted di-thioether were attached to the surface of ultrasmall gold nanoparticles (2 nm) by copper-catalyzed azide–alkyne cycloaddition (click chemistry). They showed a strong fluorescence and were well water-dispersible, in contrast to the dissolved [...] Read more.

Three different alkyne-terminated aggregation-induced emission molecules based on a para-substituted di-thioether were attached to the surface of ultrasmall gold nanoparticles (2 nm) by copper-catalyzed azide–alkyne cycloaddition (click chemistry). They showed a strong fluorescence and were well water-dispersible, in contrast to the dissolved AIE molecules. The AIE-loaded nanoparticles were not cytotoxic and easily penetrated the membrane of HeLa cells, paving the way for an intracellular application of AIE molecules, e.g., for imaging. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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21 pages, 3297 KiB

Open AccessArticle

Developing Novel Fabrication and Optimisation Strategies on Aggregation-Induced Emission Nanoprobe/Polyvinyl Alcohol Hydrogels for Bio-Applications

by Javad Tavakoli, Jesus Shrestha, Sajad R. Bazaz, Maryam A. Rad, Majid E. Warkiani, Colin L. Raston, Joanne L. Tipper and Youhong Tang

Molecules 2022, 27(3), 1002; https://doi.org/10.3390/molecules27031002 - 2 Feb 2022

Cited by 2 | Viewed by 2661

Abstract

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix [...] Read more.

The current study describes a new technology, effective for readily preparing a fluorescent (FL) nanoprobe-based on hyperbranched polymer (HB) and aggregation-induced emission (AIE) fluorogen with high brightness to ultimately develop FL hydrogels. We prepared the AIE nanoprobe using a microfluidic platform to mix hyperbranched polymers (HB, generations 2, 3, and 4) with AIE (TPE-2BA) under shear stress and different rotation speeds (0–5 K RPM) and explored the FL properties of the AIE nanoprobe. Our results reveal that the use of HB generation 4 exhibits 30-times higher FL intensity compared to the AIE alone and is significantly brighter and more stable compared to those that are prepared using HB generations 3 and 2. In contrast to traditional methods, which are expensive and time-consuming and involve polymerization and post-functionalization to develop FL hyperbranched molecules, our proposed method offers a one-step method to prepare an AIE-HB nanoprobe with excellent FL characteristics. We employed the nanoprobe to fabricate fluorescent injectable bioadhesive gel and a hydrogel microchip based on polyvinyl alcohol (PVA). The addition of borax (50 mM) to the PVA + AIE nanoprobe results in the development of an injectable bioadhesive fluorescent gel with the ability to control AIEgen release for 300 min. When borax concentration increases two times (100 mM), the adhesion stress is more than two times bigger (7.1 mN/mm²) compared to that of gel alone (3.4 mN/mm²). Excellent dimensional stability and cell viability of the fluorescent microchip, along with its enhanced mechanical properties, proposes its potential applications in mechanobiology and understanding the impact of microstructure in cell studies. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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12 pages, 3559 KiB

Open AccessArticle

‘Aggregation-Induced Emission’ Active Mono-Cyclometalated Iridium(III) Complex Mediated Efficient Vapor-Phase Detection of Dichloromethane

by Pramod C. Raichure, Vishal Kachwal and Inamur Rahaman Laskar

Molecules 2022, 27(1), 202; https://doi.org/10.3390/molecules27010202 - 29 Dec 2021

Cited by 8 | Viewed by 2638

Abstract

Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an ‘Aggregation-induced Emission’ (AIE) active mono-cyclometalated iridium(III)-based (M1) probe molecule, which detects DCM sensitively and selectively [...] Read more.

Selective vapor-phase detection of dichloromethane (DCM) is a challenge, it being a well-known hazardous volatile organic solvent in trace amounts. With this in mind, we have developed an ‘Aggregation-induced Emission’ (AIE) active mono-cyclometalated iridium(III)-based (M1) probe molecule, which detects DCM sensitively and selectively in vapor phase with a response time <30 s. It reveals a turn-on emission (non-emissive to intense yellow) on exposing DCM vapor directly to the solid M1. The recorded detection limit is 4.9 ppm for DCM vapor with pristine M1. The mechanism of DCM detection was explored. Moreover, the detection of DCM vapor by M1 was extended with a low-cost filter paper as the substrate. The DCM is weakly bound with the probe and can be removed with a mild treatment, so, notably, the probe can be reused. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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13 pages, 2439 KiB

Open AccessArticle

Aggregation-Enhanced Room-Temperature Phosphorescence from Au(I) Complexes Bearing Mesogenic Biphenylethynyl Ligands

by Andriani Furoida, Misato Daitani, Kyohei Hisano and Osamu Tsutsumi

Molecules 2021, 26(23), 7255; https://doi.org/10.3390/molecules26237255 - 30 Nov 2021

Cited by 6 | Viewed by 2476

Abstract

Gold(I) complexes, enabling to form linear coordination geometry, are promising materials for manifesting both aggregation-induced emission (AIE) behavior due to strong intermolecular Au–Au (aurophilic) interactions and liquid crystalline (LC) nature depending on molecular geometry. In this study, we synthesized several gold(I) complexes with [...] Read more.

Gold(I) complexes, enabling to form linear coordination geometry, are promising materials for manifesting both aggregation-induced emission (AIE) behavior due to strong intermolecular Au–Au (aurophilic) interactions and liquid crystalline (LC) nature depending on molecular geometry. In this study, we synthesized several gold(I) complexes with rod-like molecular skeletons where we employed a mesogenic biphenylethynyl ligand and an isocyanide ligand with flexible alkoxyl or alkyl chains. The AIE behavior and LC nature were investigated experimentally and computationally. All synthesized gold(I) complexes exhibited AIE properties and, in crystal, room-temperature phosphorescence (RTP) with a relatively high quantum yields of greater than 23% even in air. We have demonstrated that such strong RTP are drastically changed depending on the crystal-size and/or crystal growth process that changes quality of crystals as well as the aggregate structure, of e.g., Au–Au distance. Moreover, the complex with longer flexible chains showed LC nature where RTP can be observed. We expect these rod-like gold(I) complexes to have great potential in AIE-active LC phosphorescent applications such as linearly/circularly polarizing phosphorescence materials. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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Review

Jump to: Research, Other

22 pages, 6538 KiB

Open AccessReview

Polymerization-Enhanced Photophysical Performances of AIEgens for Chemo/Bio-Sensing and Therapy

by Shanshan Huang, Guogang Shan, Chao Qin and Shunjie Liu

Molecules 2023, 28(1), 78; https://doi.org/10.3390/molecules28010078 - 22 Dec 2022

Cited by 5 | Viewed by 2224

Abstract

AIE polymers have been extensively researched in the fields of OLEDs, sensing, and cancer treatment since its first report in 2003, which have achieved numerous breakthroughs during the years. In comparison with small molecules, it can simultaneously combine the unique advantages of AIE [...] Read more.

AIE polymers have been extensively researched in the fields of OLEDs, sensing, and cancer treatment since its first report in 2003, which have achieved numerous breakthroughs during the years. In comparison with small molecules, it can simultaneously combine the unique advantages of AIE materials and the polymer itself, to further enhance their corresponding photophysical performances. In this review, we enumerate and discuss the common construction strategies of AIE-active polymers and summarize the progress of research on polymerization enhancing luminescence, photosensitization, and room-temperature phosphorescence (RTP) with their related applications in chemo/bio-sensing and therapy. To conclude, we also discuss current challenges and prospects of the field for future development. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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19 pages, 7397 KiB

Open AccessReview

NIR-II AIEgens with Photodynamic Effect for Advanced Theranostics

by Shuai Yin, Jianwen Song, Dongfang Liu, Kaikai Wang and Ji Qi

Molecules 2022, 27(19), 6649; https://doi.org/10.3390/molecules27196649 - 6 Oct 2022

Cited by 6 | Viewed by 3083

Abstract

Phototheranostics that concurrently integrates accurate diagnosis (e.g., fluorescence and photoacoustic (PA) imaging) and in situ therapy (e.g., photodynamic therapy (PDT) and photothermal therapy (PTT)) into one platform represents an attractive approach for accelerating personalized and precision medicine. The second near-infrared window (NIR-II, 1000–1700 [...] Read more.

Phototheranostics that concurrently integrates accurate diagnosis (e.g., fluorescence and photoacoustic (PA) imaging) and in situ therapy (e.g., photodynamic therapy (PDT) and photothermal therapy (PTT)) into one platform represents an attractive approach for accelerating personalized and precision medicine. The second near-infrared window (NIR-II, 1000–1700 nm) has attracted considerable attention from both the scientific community and clinical doctors for improved penetration depth and excellent spatial resolution. NIR-II agents with a PDT property as well as other functions are recently emerging as a powerful tool for boosting the phototheranostic outcome. In this minireview, we summarize the recent advances of photodynamic NIR-II aggregation-induced emission luminogens (AIEgens) for biomedical applications. The molecular design strategies for tuning the electronic bandgaps and photophysical energy transformation processes are discussed. We also highlight the biomedical applications, such as image-guided therapy of both subcutaneous and orthotopic tumors, and multifunctional theranostics in combination with other treatment methods, including chemotherapy and immunotherapy; and the precise treatment of both tumor and bacterial infection. This review aims to provide guidance for PDT agents with long-wavelength emissions to improve the imaging precision and treatment efficacy. We hope it will provide a comprehensive understanding about the chemical structure–photophysical property–biomedical application relationship of NIR-II luminogens. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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17 pages, 7287 KiB

Open AccessReview

Near-Infrared-Emissive AIE Bioconjugates: Recent Advances and Perspectives

by Wenshuai Luo, Yonghong Tan, Yixiong Gui, Dingyuan Yan, Dong Wang and Ben Zhong Tang

Molecules 2022, 27(12), 3914; https://doi.org/10.3390/molecules27123914 - 18 Jun 2022

Cited by 10 | Viewed by 3742

Abstract

Near-infrared (NIR) fluorescence materials have exhibited formidable power in the field of biomedicine, benefiting from their merits of low autofluorescence background, reduced photon scattering, and deeper penetration depth. Fluorophores possessing planar conformation may confront the shortcomings of aggregation-caused quenching effects at the aggregate [...] Read more.

Near-infrared (NIR) fluorescence materials have exhibited formidable power in the field of biomedicine, benefiting from their merits of low autofluorescence background, reduced photon scattering, and deeper penetration depth. Fluorophores possessing planar conformation may confront the shortcomings of aggregation-caused quenching effects at the aggregate level. Fortunately, the concept of aggregation-induced emission (AIE) thoroughly reverses this dilemma. AIE bioconjugates referring to the combination of luminogens showing an AIE nature with biomolecules possessing specific functionalities are generated via the covalent conjugation between AIEgens and functional biological species, covering carbohydrates, peptides, proteins, DNA, and so on. This perfect integration breeds unique superiorities containing high brightness, good water solubility, versatile functionalities, and prominent biosafety. In this review, we summarize the recent progresses of NIR-emissive AIE bioconjugates focusing on their design principles and biomedical applications. Furthermore, a brief prospect of the challenges and opportunities of AIE bioconjugates for a wide range of biomedical applications is presented. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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Open AccessReview

Recent Advances in Aggregation-Induced Emission Active Materials for Sensing of Biologically Important Molecules and Drug Delivery System

by Geeta A. Zalmi, Ratan W. Jadhav, Harshad A. Mirgane and Sheshanath V. Bhosale

Molecules 2022, 27(1), 150; https://doi.org/10.3390/molecules27010150 - 27 Dec 2021

Cited by 26 | Viewed by 7048

Abstract

The emergence and development of aggregation induced emission (AIE) have attracted worldwide attention due to its unique photophysical phenomenon and for removing the obstacle of aggregation-caused quenching (ACQ) which is the most detrimental process thereby making AIE an important and promising aspect in [...] Read more.

The emergence and development of aggregation induced emission (AIE) have attracted worldwide attention due to its unique photophysical phenomenon and for removing the obstacle of aggregation-caused quenching (ACQ) which is the most detrimental process thereby making AIE an important and promising aspect in various fields of fluorescent material, sensing, bioimaging, optoelectronics, drug delivery system, and theranostics. In this review, we have discussed insights and explored recent advances that are being made in AIE active materials and their application in sensing, biological cell imaging, and drug delivery systems, and, furthermore, we explored AIE active fluorescent material as a building block in supramolecular chemistry. Herein, we focus on various AIE active molecules such as tetraphenylethylene, AIE-active polymer, quantum dots, AIE active metal-organic framework and triphenylamine, not only in terms of their synthetic routes but also we outline their applications. Finally, we summarize our view of the construction and application of AIE-active molecules, which thus inspiring young researchers to explore new ideas, innovations, and develop the field of supramolecular chemistry in years to come. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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15 pages, 2237 KiB

Open AccessPerspective

Controlling Molecular Aggregation-Induced Emission by Controlled Polymerization

by Yinyin Bao

Molecules 2021, 26(20), 6267; https://doi.org/10.3390/molecules26206267 - 16 Oct 2021

Cited by 8 | Viewed by 3389

Abstract

In last twenty years, the significant development of AIE materials has been witnessed. A number of small molecules, polymers and composites with AIE activity have been synthesized, with some of these exhibiting great potential in optoelectronics and biomedical applications. Compared to AIE small [...] Read more.

In last twenty years, the significant development of AIE materials has been witnessed. A number of small molecules, polymers and composites with AIE activity have been synthesized, with some of these exhibiting great potential in optoelectronics and biomedical applications. Compared to AIE small molecules, macromolecular systems—especially well-defined AIE polymers—have been studied relatively less. Controlled polymerization methods provide the efficient synthesis of well-defined AIE polymers with varied monomers, tunable chain lengths and narrow dispersity. In particular, the preparation of single-fluorophore polymers through AIE molecule-initiated polymerization enables the systematic investigation of the structure–property relationships of AIE polymeric systems. Here, the main polymerization techniques involved in these polymers are summarized and the key parameters that affect their photophysical properties are analyzed. The author endeavored to collect meaningful information from the descriptions of AIE polymer systems in the literature, to find connections by comparing different representative examples, and hopes eventually to provide a set of general guidelines for AIE polymer design, along with personal perspectives on the direction of future research. Full article

(This article belongs to the Special Issue Aggregation-Induced Emission: Commemorative Issue of the 20th Anniversary of AIE Research and the 65th Birthday of Professor Ben Zhong Tang)

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