Facilely prepared blue-green light sensitive curcuminoids with excellent bleaching properties as high performance photosensitizers in cationic and free radical photopolymerization

Han, Weixiang; Fu, Hao; Xue, Tanlong; Liu, Tongzheng; Wang, Yong; Wang, Tao

doi:10.1039/c8py00166a

Cited by 70 publications

(39 citation statements)

References 46 publications

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“…The values of free energy changes Δ G S1 calculated using the classical Rehm–Weller equation for the corresponding electron transfer process were all negative, which confirms that the electron transfer process was thermodynamically favored (Table ). On the basis of the above information and previous related studies, the interaction between excited BF 2 Curs and ground state ONI could be depicted in the following reactions

{BF}_{2} Curs \to^{1} {BF}_{2} Curs (h ν) and^{1} {BF}_{2} Curs \to^{3} {BF}_{2} Curs

^{1, 3} {BF}_{2} Curs + {Ar}_{2} I^{+} \to {BF}_{2} {Curs}^{• +} + {Ar}_{2} I^{•}

{Ar}_{2} I^{•} \to ArI + {Ar}^{•}

…”

Section: Methodsmentioning

confidence: 67%

“…The interaction rate constants (k q ) of BF 2 Curs /ONI were calculated and presented in Table 2 . These demonstrate the presence of electron transfer between the excited singlet states of BF 2 Curs and the ground state of ONI and that the process is diffusion‐controlled . The redox potentials obtained from Figure S7, Supporting Information indicated BF 2 Cur4 is most susceptible to be oxidized, while BF 2 Cur1 and BF 2 Cur2 are relatively difficult to be oxidized.…”

Section: Methodsmentioning

confidence: 88%

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Curcuminoid‐Based Difluoroboron Dyes as High‐Performance Photosensitizers in Long‐Wavelength (Yellow and Red) Cationic Photopolymerization

Han

You

et al. 2019

Macromol. Rapid Commun.

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derivatives (DAAQs) have a remarkable influence on the initiating efficiency of the DAAQs-based photo initiating systems. [5] In such photo initiating systems, dyes play a significant role in absorbing light and interacting with other additives to generate initiating species. Dyes determine the suitable spectral scope and initiating efficiency of the photoinitiating systems. The design of facilely prepared dyes with excellent light absorption properties at long-wavelength and the development of high-performance dye-sensitized cationic photoinitiating systems still remain challenging. Difluoroboron β-diketonate dyes are highly luminescent organboron complexes that exhibit wide applications in biosensing, bioimaging, and optoelectronic devices due to their rich photophysical properties (strong fluorescence, large extinction coefficients, and two-photon excited fluorescence). [6] However, to the best of our knowledge, no attempts have been made to use these dyes in cationic polymerization. Bellinger et al. reported a series of curcuminoid and hemicurcuminoid-based difluoroboron dyes (BF 2 Curs). [7] The reported dyes exhibit excellent light absorption ability at 450−650 nm and suitable redox potentials, which endow them with the potential for use in dye-sensitive long-wavelength photopolymerization.In the present paper, four BF 2 Curs were prepared (Scheme 1). Their light absorption properties were investigated. Furthermore, the photoinitiating efficiency of BF 2 Curs in the presence of an iodonium salt (ONI) for the CP of diglycidyl ether of bisphenol A (DGEBA) and tri(ethylene glycol) divinyl ether (DVE-3) was analyzed upon exposure to yellow and red LEDs. For comparison, the reported OBN-based photoinitiating systems were tested under the same experimental conditions. The photochemical reactivity between BF 2 Curs and iodonium salts was investigated. The mechanisms involved in the formation of initiation species were proposed, and structure−activity relationships of the BF 2 Curs-based photo initiating systems were discussed.The UV-vis absorption spectra of BF 2 Curs (BF 2 Cur1, BF 2 Cur2, BF 2 Cur3, and BF 2 Cur4) and OBN in DCM are presented in Figure 1. Their absorption maxima (λ max ) and extinction coefficients (ε) at λ max and at the maximum emission wavelengths of different LEDs are summarized in Table 1. As illustrated, BF 2 Curs showed much higher light absorption intensity than OBN at λ max . Notably, BF 2 Curs demonstrated satisfactory overlap with the emission wavelengths of yellow (585 nm) and red (625 nm) LEDs. The extinction coefficients of Photopolymerization Difluoroboron β-diketonate dyes are reported to exhibit excellent photophysical properties (e.g., broad absorption and large extinction coefficients) and have the potential to act as high-performance photosensitizers in cationic photopolymerization (CP). In this study, four curcuminoid-based difluoroboron dyes (BF 2 Curs) are prepared. Their ability to initiate the CP of epoxides or vinyl ethers in combination with an iodonium salt under yel...

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{BF}_{2} Curs \to^{1} {BF}_{2} Curs (h ν) and^{1} {BF}_{2} Curs \to^{3} {BF}_{2} Curs

^{1, 3} {BF}_{2} Curs + {Ar}_{2} I^{+} \to {BF}_{2} {Curs}^{• +} + {Ar}_{2} I^{•}

{Ar}_{2} I^{•} \to ArI + {Ar}^{•}

…”

Section: Methodsmentioning

confidence: 67%

Section: Methodsmentioning

confidence: 88%

Curcuminoid‐Based Difluoroboron Dyes as High‐Performance Photosensitizers in Long‐Wavelength (Yellow and Red) Cationic Photopolymerization

Han

You

et al. 2019

Macromol. Rapid Commun.

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“…Compared to the traditional Type I cleavage systems and Type II H abstraction systems, dye-photosensitized systems, which can extensively use LEDs and can be excited under long-wavelength light, are attracting more intention in photopolymerization [ 18 , 19 ]. Due to its good optical properties, carbazole has been frequently used to design functional PIs [ 20 , 21 ]. Moreover, carbazole is an excellent electron donor that can be oxidized at low potential.…”

Section: Introductionmentioning

confidence: 99%

Monocomponent Photoinitiators based on Benzophenone-Carbazole Structure for LED Photoinitiating Systems and Application on 3D Printing

et al. 2020

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In this article, different substituents (benzoyl, acetyl, styryl) are introduced onto the carbazole scaffold to obtain 8 novel carbazole derivatives. Interestingly, a benzoyl substituent, connected to a carbazole group, could form a benzophenone moiety, which composes a monocomponent Type II benzophenone-carbazole photoinitiator (PI). The synergetic effect of the benzophenone moiety and the amine in the carbazole moiety is expected to produce high performance photoinitiating systems (PISs) for the free radical photopolymerization (FRP). For different substituents, clear effects on the light absorption properties are demonstrated using UV-Visible absorption spectroscopy. Benzophenone-carbazole PIs can initiate the FRP of acrylates alone (monocomponent Type II photoinitiator behavior). In addition, fast polymerization rates and high function conversions of acrylate are observed when an amine and/or an iodonium salt are added in systems. Benzophenone-carbazole PIs have good efficiencies in cationic photopolymerization (CP) upon LED @ 365 nm irradiation in the presence of iodonium salt. In contrast, other PIs without synergetic effect demonstrate unsatisfied photopolymerization profiles in the same conditions. The best PIS identified for the free radical photopolymerization were used in three-dimensional (3D) printing. Steady state photolysis and fluorescence quenching experiments were carried out to investigate the reactivity and the photochemistry and photophysical properties of PIs. The free radicals, generated from the studied PISs, are detected by the electron spin resonance - spin trapping technique. The proposed chemical mechanisms are provided and the structure/reactivity/efficiency relationships are also discussed. All the results showed that the benzophenone-carbazole PIs have a good application potential, and this work provides a rational design route for PI molecules. Remarkably, BPC2-BPC4, C6, C8 were never synthetized before; therefore, 5 of the 8 compounds are completely new.

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“…Recently, the development of biosourced or bioinspired photoinitiators has become an active research field. [149][150][151][152][153][154][155][156][157][158] Indeed, natural dyes offer a unique opportunity to design biocompatible polymers. [149,[159][160] These photoinitiators can also be cheap, as these compounds originate from renewable resources.…”

Section: Ferrocene-based Chalconesmentioning

confidence: 99%

Recent advances on iron-based photoinitiators of polymerization

Dumur

2020

European Polymer Journal

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With regards to the environmental and safety concerns raised nowadays by the polymer industry, polymerization processes requiring light as the activation source are currently knowing a revival of interest after decades of disinterest. Recent progresses in photopolymerization are notably sustained by the development of new polymerization application namely 3D and 4D printing enabling an unprecedented access to structures of incredible complexity. Parallel to the manufacturing process, the polymer material itself and its composition are also facing numerous questions concerning their environmental and human health impacts. Beyond the monomers, the different additives introduced in the resin can also be potentially toxic so that a great deal of efforts is currently done to develop new photoinitiators with a toxicity assessed as being insignificant. In this field, iron-based metal complexes are candidates of choice due to the clinical demonstration of their very low toxicities. Among iron complexes, ferrocene is among the most widely studied iron-based metallocene. Due to its unique and reversible electrochemical properties as well as their absorption centred in the visible range, numerous photoinitiators have been developed with ferrocene or its oxidized form i.e. ferrocenium. Parallel to this, the remarkable electrochemical properties of ferrocenium made it an excellent candidate for its incorporation in photoinitiating systems. However, interest for iron-based photoinitiators was not limited to ferrocene and ferrocenium, and Schiff base complexes were also successfully used as initiators of polymerization. In this review, an overview of the different iron-based photoinitiating systems reported to date is presented. More precisely, if iron-based photoinitiators are developed since 50 years, a special focus will be done on photoinitiators designed for recent polymerization conditions, namely, under visible light and low light intensity.

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Facilely prepared blue-green light sensitive curcuminoids with excellent bleaching properties as high performance photosensitizers in cationic and free radical photopolymerization

Abstract: Four blue-green light sensitive curcuminoids have been prepared using a facile method. High performances were found as photosensitizers in cationic and free radical photopolymerzation.

Cited by 70 publications

References 46 publications

Curcuminoid‐Based Difluoroboron Dyes as High‐Performance Photosensitizers in Long‐Wavelength (Yellow and Red) Cationic Photopolymerization

Curcuminoid‐Based Difluoroboron Dyes as High‐Performance Photosensitizers in Long‐Wavelength (Yellow and Red) Cationic Photopolymerization

Monocomponent Photoinitiators based on Benzophenone-Carbazole Structure for LED Photoinitiating Systems and Application on 3D Printing

Recent advances on iron-based photoinitiators of polymerization

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