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Charge delocalization and hyperpolarizability in ionic liquids. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2021.118153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Shurygin AV, Vovna VI, Korochentsev VV, Mirochnik AG, Kalinovskaya IV, Sergienko VI. Optical properties and electronic structure of Eu(III) complexes with HMPA and TPPO. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 250:119397. [PMID: 33422875 DOI: 10.1016/j.saa.2020.119397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/01/2020] [Accepted: 12/26/2020] [Indexed: 06/12/2023]
Abstract
Two adducts of Eu(III) tris-hexofluoroacetylacetonate with HMPA (OP(N(CH3)2)3, hexamethylphosphotriamide) and TPPO (OP(C6H5)3, triphenylphosphine oxide) were studied by optical spectroscopy and quantum chemistry (DFT/TD-DFT). The structure of the higher occupied molecular orbitals (MO) of the two adducts determines differences in the position of the excitation band maximum of hfac ligands. According to the calculation data, all excited states are caused by the transition to 3 vacant π4* MOs of hfac ligands. Optical spectra of absorption, excitation and luminescence are obtained and interpreted. The peculiarity of the HOMO-LUMO structure, the low value of the energy gap, and the broadened absorption region of hfac ligands compensate the low absorbance ability of the groups N(CH3)2 in a region of 220-360 nm for the adduct Eu(hfac)3(HMPA)2, reducing the luminescence intensity by only 5-10% relative to the adduct of the Eu(III) complex with TPPO ligands.
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Affiliation(s)
- A V Shurygin
- Far Eastern Federal University, 8 Sukhanova St., Vladivostok, Russia
| | - V I Vovna
- Far Eastern Federal University, 8 Sukhanova St., Vladivostok, Russia.
| | - V V Korochentsev
- Far Eastern Federal University, 8 Sukhanova St., Vladivostok, Russia
| | - A G Mirochnik
- Institute of Chemistry, FEB RAS, 159 Prosp. 100-letiya Vladivostoka, Vladivostok, Russia
| | - I V Kalinovskaya
- Institute of Chemistry, FEB RAS, 159 Prosp. 100-letiya Vladivostoka, Vladivostok, Russia
| | - V I Sergienko
- Far Eastern Branch, RAS, 50 Svetlanskaya St., Vladivostok, Russia
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Li Q, Qiu J, Liu H, Chen X. A luminescent lyotropic liquid crystal with UV irradiation induced photochromism. SOFT MATTER 2020; 16:1170-1178. [PMID: 31934710 DOI: 10.1039/c9sm02366f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Multicolored photoluminescence induced by UV irradiation in soft materials has invaluable potential in display and detection applications. Here, an ionic liquid (ethylammonium nitrate, EAN)-mediated luminescent lyotropic liquid crystal (LLC) has been fabricated, where an europium complex with two ligands (Eu(DBM)3BQ, DBM = dibenzoylmethane and BQ = 2,2'-biquinoline) was doped. The obtained LLC exhibited enhanced fluorescence intensity and lifetime compared to those of Eu(DBM)3BQ in EAN solution. Interestingly, the luminescent LLC color from the initial red emission of the complex was changed gradually to green when the UV exposure was extended. Though the DBM ligand displayed the typical photo-degradation, the emission intensity of BQ increased drastically. A mechanism based on an UV-induced trans-to-cis isomerization of BQ was proposed to explain such an unusual luminescence phenomenon. Both the experimental and computational results indicated an intra ligand charge transfer (ILCT) accompanied with the BQ isomerization under continuous UV irradiation, which resulted in the enhanced green light emission. The results obtained here are referable for better understanding the interplay between weak interactions and modulation of novel lanthanide-based photochromism systems under UV exposure.
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Affiliation(s)
- Qingrun Li
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, China.
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Shurygin AV, Vovna VI, Korochentsev VV, Mirochnik AG, Sergienko VI. Electronic Structure of Eu(III) Adducts with OP(C6H5)3 and OP[NMe2]3. J STRUCT CHEM+ 2020. [DOI: 10.1134/s0022476619120084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Li Q, Yi S, Chen X. Luminescent Vesicles and Lyotropic Liquid Crystals in Ethylammonium Nitrate from a Partially Amphiphilic Eu Complex. ACS OMEGA 2019; 4:9843-9849. [PMID: 31460075 PMCID: PMC6648430 DOI: 10.1021/acsomega.9b01215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 05/24/2019] [Indexed: 06/10/2023]
Abstract
Soft luminescent materials have attracted much attention because of their self-assembled and controllable properties. To explore their facile and effective fabrication ways, we report here the self-assembling of luminescent vesicles and lyotropic liquid crystals (LLCs) in a protic ionic liquid, ethylammonium nitrate, by a partially amphiphilic europium β-diketonate complex (Eu(III)) with a 1-dodecyl-3-methylimidazolium cation as the counter ion. An interesting result came from the complex-induced vesicle formation of corresponding amphiphile, 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br), which has been rarely reported in the past. It was the interaction between the Eu(III) and imidazolium group that changed the critical packing parameter of [C12mim]Br, which finally resulted in the occurrence of vesicles. The obtained vesicle aggregates exhibited enhanced fluorescence intensity and lifetime compared to those of Eu(III) solution. Meanwhile, a hexagonal LLC phase with better fluorescence properties was found at higher [C12mim]Br concentration. The obtained photophysical data confirmed that the order degree of Eu(III)-containing aggregates could effectively increase the energy transition efficiency of ligands. The better luminescent properties of LLC resulted from the stronger stabilizing and binding effects on Eu(III) in LLC than that in vesicles, which might be caused by closer molecular packing in LLC. The results presented here will not only expand the strategy of constructing lanthanide-containing luminescent soft materials in ionic liquids but also provide reference to better understand the effect of organized aggregates on luminescence properties.
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Affiliation(s)
- Qingrun Li
- Key
Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, China
| | - Sijing Yi
- College
of Arts and Sciences, Shanxi Agricultural
University, Taigu 030801, China
| | - Xiao Chen
- Key
Laboratory of Colloid and Interface Chemistry, Ministry of Education, Shandong University, Jinan 250100, China
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Lei N, Feng L, Chen X. Zwitterionic Surfactant Micelle-Directed Self-Assembly of Eu-Containing Polyoxometalate into Organized Nanobelts with Improved Emission and pH Responsiveness. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:4370-4379. [PMID: 30813733 DOI: 10.1021/acs.langmuir.9b00261] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recently, hybrid coassembly between polyoxometalates (POMs) and cationic building blocks provides an efficient strategy to greatly optimize POMs' functionality as well as their aggregate structural diversity. Adaptive hybrid supramolecular materials with enhanced luminescence have then been obtained from lanthanide-containing POMs. In this work, a commercially available and pH-switchable zwitterionic surfactant, tetradecyldimethylamine oxide (C14DMAO), was chosen to coassemble with a lanthanide-containing anionic POM [Na9(EuW10O36)·32H2O, abbreviated as EuW10] in water. The much improved red-emitting luminescent nanobelts at a C14DMAO/EuW10 molar ratio ( R) of 20 were obtained, which exhibited longer luminescence lifetime and higher quantum yield compared with EuW10 aqueous solution. After careful characterization of morphology and structure of nanobelts, an unusual axial lamellar aggregation arrangement mechanism was proposed. It was the partial protonation of C14DMAO at the solution pH of about 6.5 that led to positively charged micelles, being bridged by anionic EuW10 clusters to aggregate into such novel nanobelts under the synergetic effects of appropriate electrostatic, hydrogen-bonding, and hydrophobic interactions. The resulted pH-responsive luminescent nanobelts and their aggregation model should offer attractive references for preparing smart optical supramolecular materials.
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Affiliation(s)
- Nana Lei
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education , Shandong University , Jinan 250100 , China
| | - Lei Feng
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education , Shandong University , Jinan 250100 , China
| | - Xiao Chen
- Key Laboratory of Colloid and Interface Chemistry, Ministry of Education , Shandong University , Jinan 250100 , China
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Lei N, Shen D, Chen X. Highly luminescent and multi-sensing aggregates co-assembled from Eu-containing polyoxometalate and an enzyme-responsive surfactant in water. SOFT MATTER 2019; 15:399-407. [PMID: 30601546 DOI: 10.1039/c8sm02276c] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hybrid co-assembly of polyoxometalates (POMs) with cationic organic matrices offers a preferable way to greatly enhance POM functionality as well as processability. Thus, multi-stimulus responsive supramolecular materials based on lanthanide-containing POMs with improved luminescence may be fabricated from appropriate components through this convenient strategy. Herein, we reported that the co-assembly of Na9(EuW10O36)·32H2O (EuW10) and a commercially available cationic surfactant, myristoylcholine chloride (Myr), in water could produce enhanced red-emitting luminescent aggregates, with their photophysical properties highly dependent on the molar ratio (R) between Myr and EuW10. The R of 36 was finally selected owing to the displayed superior luminescence intensity and good aggregate stability. The Myr/EuW10 hybrids induced by electrostatic and hydrophobic forces presented practically as multilamellar spheres with diameters varying from 80 to 300 nm. Compared to an aqueous solution of EuW10 nanoclusters, a 12-fold increase in absolute luminescence quantum yield (∼23.3%) was observed for the hybrid spheres, which was ascribed to the efficient shielding of water molecules. An unusual aggregation arrangement mechanism and the excellent photophysical properties of these aggregates were thoroughly investigated. Both the enzyme substrate character of Myr and the sensitive coordination structure of EuW10 to the surrounding environment made Myr/EuW10 aggregates exhibit multi-stimulus responsiveness to enzymes, pH, and transition metal ions, thus providing potential applications in fluorescence sensing, targeted-release, and optoelectronics.
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Affiliation(s)
- Nana Lei
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, China.
| | - Dazhong Shen
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, 250014, China
| | - Xiao Chen
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, China.
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Lei N, Shen D, Wang J, Chen X. Flexible and enhanced multicolor-emitting films co-assembled by lanthanide complexes and a polymerizable surfactant in aqueous solution. SOFT MATTER 2018; 14:9143-9152. [PMID: 30283957 DOI: 10.1039/c8sm01603h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Lanthanide complex doped lyotropic liquid crystals (LLCs) are soft materials which are impressive due to their excellent luminescence efficiencies and stabilities. The introduction of lanthanide complexes into polymerizable LLCs, however, may produce organized films with better optical and mechanical properties through in situ photopolymerization. An environmentally friendly strategy to fabricate flexible multicolor-emitting films has been developed through co-assembling red-/green-emitting trisdipicolinate lanthanide complexes [choline]3[Ln(DPA)3] (Ln-DPA, Ln = Eu, Tb) into LLC matrices mainly via electrostatic interaction and further photopolymerization. The LLCs were constructed from a polymerizable surfactant, 3-dodecyl-1-vinylimidazolium bromide (C12VIMBr), in aqueous solution. The maintenance of the well-defined LLC nanostructures in the luminescent films was validated by small-angle X-ray scattering (SAXS) as well as scanning electron microscopy (SEM) measurements. Remarkably, the lifetime and absolute luminescence quantum efficiency of such films have been improved significantly compared with those of the corresponding solid Eu-DPA complex or in aqueous solution and LLC matrices. Through tuning the molar ratio of Eu-DPA to Tb-DPA complexes, the emission color of the films could be finely-tailored between red and green in the CIE chromaticity diagram. Furthermore, the films also possessed certain mechanical strength and stability against pH, metal ions, and temperature, indicating their potential application as robust luminescent materials.
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Affiliation(s)
- Nana Lei
- Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan, 250100, China.
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