scholarly journals Emission solvatochromic, solid-state and aggregation-induced emissive α-pyrones and emission-tuneable 1H-pyridines by Michael addition–cyclocondensation sequences

2019 ◽  
Vol 15 ◽  
pp. 2684-2703 ◽  
Author(s):  
Natascha Breuer ◽  
Irina Gruber ◽  
Christoph Janiak ◽  
Thomas J J Müller

Starting from substituted alkynones, α-pyrones and/or 1H-pyridines were generated in a Michael addition–cyclocondensation with ethyl cyanoacetate. The peculiar product formation depends on the reaction conditions as well as on the electronic substitution pattern of the alkynone. While electron-donating groups furnish α-pyrones as main products, electron-withdrawing groups predominantly give the corresponding 1H-pyridines. Both heterocycle classes fluoresce in solution and in the solid state. In particular, dimethylamino-substituted α-pyrones, as donor–acceptor systems, display remarkable photophysical properties, such as strongly red-shifted absorption and emission maxima with daylight fluorescence and fluorescence quantum yields up to 99% in solution and around 11% in the solid state, as well as pronounced emission solvatochromism. Also a donor-substituted α-pyrone shows pronounced aggregation-induced emission enhancement.

2016 ◽  
Vol 12 ◽  
pp. 825-834 ◽  
Author(s):  
Andreea Petronela Diac ◽  
Ana-Maria Ţepeş ◽  
Albert Soran ◽  
Ion Grosu ◽  
Anamaria Terec ◽  
...  

New indeno[1,2-c]pyran-3-ones bearing different substituents at the pyran moiety were synthesized and their photophysical properties were investigated. In solution all compounds were found to be blue emitters and the trans isomers exhibited significantly higher fluorescence quantum yields (relative to 9,10-diphenylanthracene) as compared to the corresponding cis isomers. The solid-state fluorescence spectra revealed an important red shift of λmax due to intermolecular interactions in the lattice, along with an emission-band broadening, as compared to the solution fluorescence spectra.


Synthesis ◽  
2021 ◽  
Author(s):  
Xianglong Chu ◽  
Yadi Niu ◽  
Chen Ma ◽  
Xiaodong Wang ◽  
Yunliang Lin ◽  
...  

AbstractA rapid access to a series of N-heteroarene fluorophores has been developed on the basis of the palladium-catalyzed direct oxidative C–H/C–H coupling of imidazo[1,2-a]pyridines with thiophenes/furans. The photophysical properties–structure relationship was systematically investigated. The resulting N-heteroarene fluorophores present color-tunable emissions (λem: 431–507 nm in CH2Cl2) and high fluorescence quantum yields (up to 91% in CH2Cl2).


2020 ◽  
Author(s):  
Dominik Göbel ◽  
Daniel Duvinage ◽  
Tim Stauch ◽  
Boris Nachtsheim

Herein, we present minimalistic single-benzene, excited-state intramolecular proton transfer (ESIPT) based fluorophores as powerful solid state emitters. The very simple synthesis gave access to all four regioisomers of nitrile-substituted 2(oxazolinyl)phenols (MW = 216.1). In respect of their emission properties they can be divided into aggregation-induced emission enhancement (AIEE) luminophores (1-CN and 2-CN), dual state emission (DSE) emitters (3-CN) and aggregation-caused quenching (ACQ) fluorophores (4‐CN). Remarkably, with compound 1-CN we discovered a minimalistic ESIPT based fluorophore with extremely high quantum yield in the solid state ΦF = 87.3% at λem = 491 nm. Furthermore, quantum yields in solution were determined up to ΦF = 63.0%, combined with Stokes shifts up till 11.300 cm–1. Temperature dependent emission mapping, crystal structure analysis and time-dependent density functional theory (TDDFT) calculations gave deep insight into the origin of the emission properties.<br>


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 445 ◽  
Author(s):  
Monika Cekaviciute ◽  
Aina Petrauskaite ◽  
Sohrab Nasiri ◽  
Jurate Simokaitiene ◽  
Dmytro Volyniuk ◽  
...  

Aiming to design blue fluorescent emitters with high photoluminescence quantum yields in solid-state, nitrogen-containing heteroaromatic 9,9-dimethylacridine was refined by tetraphenylethene and triphenylethene. Six tetra-/triphenylethene-substituted 9,9-dimethylacridines were synthesized by the Buchwald-Hartwig method with relatively high yields. Showing effects of substitution patterns, all emitters demonstrated high fluorescence quantum yields of 26–53% in non-doped films and 52–88% in doped films due to the aggregation induced/enhanced emission (AIE/AIEE) phenomena. In solid-state, the emitters emitted blue (451–481 nm) without doping and deep-blue (438–445 nm) with doping while greenish-yellow emission was detected for two compounds with additionally attached cyano-groups. The ionization potentials of the derivatives were found to be in the relatively wide range of 5.43–5.81 eV since cyano-groups were used in their design. Possible applications of the emitters were demonstrated in non-doped and doped organic light-emitting diodes with up to 2.3 % external quantum efficiencies for simple fluorescent devices. In the best case, deep-blue electroluminescence with chromaticity coordinates of (0.16, 0.10) was close to blue color standard (0.14, 0.08) of the National Television System Committee.


1995 ◽  
Vol 413 ◽  
Author(s):  
Christoph Weder ◽  
Michael J. Wagner ◽  
Mark S. Wrighton

ABSTRACTIn an effort to better understand the relationship between molecular structure and photophysical properties, we have prepared and investigated a series of novel poly(2,5-dialkoxy-p-phenyleneethynylene)s. Wide angle X-ray diffraction measurements show that the supramolecular structure can be easily and significantly influenced by the nature of substituents covalently linked to the rigid-rod polymer main chains. Polymers which have sterically hindered side chains are essentially amorphous, while those with only linear side chains can form lamellar structures with a significant degree of long-range order. High photoluminescence quantum yields, up to 0.86 in solution and 0.36 in the solid state, have been measured. While the solution quantum yields are independent of the functionalization, solid state quantum efficiencies were found to be related to the degree of long-range order in the samples. In samples with a high degree of long-range order, the close proximity of the coplanar oriented polymer backbones is assumed to lead to the formation of eximer complexes which provide non emissive decay channels and, hence, result in comparable low photoluminescence quantum yields. In samples that adopt only a small extent of long-range order, the rigid-rod conjugated polymer backbones behave as if they were ‘dissolved’ in a hydrocarbon solvent and consequently high quantum efficiencies are obtained. Preliminary results indicate the suitability of these polymers as the emitting layer in electroluminescent devices.


Synlett ◽  
2017 ◽  
Vol 29 (03) ◽  
pp. 296-300 ◽  
Author(s):  
Ali Darehkordi ◽  
Fariba Rahmani ◽  
Mahin Ramezani ◽  
Alireza Bazmandegan-Shamili

A series of novel blue-light-emitting 2H-imidazo[5,1-a]isoquinolinium chloride derivatives were synthesized by the reaction of isoquinoline with trifluoroacetimidoyl chlorides and isocyanides in dry CH2Cl2 in excellent yields. Fluorescence studies showed that the compounds absorb UV radiation and then emit blue light at about 481 nm with moderate to good fluorescence quantum yields. These compounds also showed high Stokes shifts, and can be used to develop ­ultrasensitive fluorescent molecular probes to study a variety of biological events and processes.


2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Anabela Sousa Oliveira ◽  
Dumitru Licsandru ◽  
Rica Boscencu ◽  
Radu Socoteanu ◽  
Veronica Nacea ◽  
...  

This paper deals with a series of new unsymmetrically substituted mesoporphyrins: 5-(2-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHO), 5-(3-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHM), 5-(4-hydroxyphenyl)-10,15,20-tris-phenyl-21,23-H-porphyrin (TPPOHP), 5-(2-hydroxyphenyl)-10,15,20-tris-butyl-21,23-H-porphyrin (TBPOHO), and their parent nonsubstituted compounds, respectively, 5,10,15,20-tetrakis-phenyl-21,23-H-porphyrin (TPP) and 5,10,15,20-tetrakis-butyl-21,23-H-porphyrin (TBP). Several photophysical studies were carried out to access the influence of the unsymmetrical substitution at the porphyrinic macrocycle on porthyrin's photophysical properties, especially porthyrin's efficiency as singlet oxygen sensitizers. The quantum yields of singlet oxygen generation were determined in benzene (ΦΔ(TPP) = 0.66 ± 0.05;ΦΔ(TPPOHO) = 0.69 ± 0.04;ΦΔ(TPPOHM) = 0.62 ± 0.04;ΦΔ(TPPOHP) = 0.73 ± 0.03;ΦΔ(TBP) = 0.76 ± 0.03;ΦΔ(TBPOHO) = 0.73 ± 0.02) using the 5,10,15,20-tetraphenyl-21,23-H-porphine (ΦΔ(TPP) = 0.66) and Phenazine (ΦΔ(Phz) = 0.83) as reference compounds. Their fluorescence quantum yields were found to be (Φf(TPPOHO) = 0.10 ± 0.04;Φf(TPPOHM) = 0.09 ± 0.03;Φf(TPPOHP) = 0.13 ± 0.02;Φf(TBP) = 0.08 ± 0.03 andΦf(TBPOHO) = 0.08 ± 0.02 using 5,10,15,20-tetraphenyl-21,23-H-porphine as referenceΦf(TPP) = 0.13). Singlet state lifetimes were also determined in the same solvent. All the porphyrins presented very similar fluorescence lifetimes (mean values ofτS(withO2, air equilibrated) = 9.6 ± 0.3 nanoseconds and (withoutO2, argon purged) = 10.1 ± 0.6 nanoseconds, resp.). The phosphorescence emission was found to be negligible for this series of unsymmetrically substituted mesoporphyrins, but an E-type, thermally activated, delayed fluorescence process was proved to occur at room temperature.


2013 ◽  
Vol 17 (06n07) ◽  
pp. 540-547 ◽  
Author(s):  
Altuğ Mert Sevim ◽  
İbrahim Özçeşmeci ◽  
Ahmet Gül

The synthesis of novel, symmetrical zinc(II) phthalocyanine (ZnPc) bearing four ethynylcyclohexyloxy terminal moieties was achieved by cyclotetramerization of novel 4-(2-ethynylcyclohexyloxy) phthalonitrile in pentanol in the presence of DBU and zinc acetate without any protective/deprotective chemistry. Subsequently, this new zinc(II) phthalocyanine derivative was reacted with 6-azido-hexanoic acid under "click-chemistry" conditions to give phthalocyanine-hexanoic acid conjugates linked by 1,2,3-triazole units. The new compounds have been characterized by using elemental analyses, UV-vis, FTIR, 1 H NMR and mass spectroscopic data. The aggregation properties of the compounds were investigated in different concentrations. General trends are also described for fluorescence quantum yields and lifetimes of novel zinc derivatives in tetrahydrofuran. The fluorescence of the tetrasubstituted zinc(II) phthalocyanine complexes is effectively quenched by 1,4-benzoquinone (BQ) in THF.


1982 ◽  
Vol 37 (4) ◽  
pp. 383-386
Author(s):  
D. Gloyna ◽  
A. Kawski ◽  
I. Gryczyński

Abstract Fluorescence quantum yields, φf, of donor-acceptor substituted trans-stilbenes, 1, in n-heptane and toluene depend upon the solvent dynamic viscosity η according to the relation ln(φf-1 - 1) = a ln(η-1)+b. By changing the temperature (278 < T < 343 K) the viscosity was varied. The viscosity dependence of φf can be accounted for by a corresponding viscosity depending radiations less deactivation of the S1 state, which in low solutions is first of all determined by the intramolecular donor-acceptor and universal intermolecular solute-solvent interactions, and then by viscosity.


2019 ◽  
Vol 21 (13) ◽  
pp. 7174-7182 ◽  
Author(s):  
Nannan Jian ◽  
Kai Qu ◽  
Hua Gu ◽  
Lie Zou ◽  
Ximei Liu ◽  
...  

Triazolopyridine–thiophene fluorophores exhibit high fluorescence quantum yields both in solution (80–89%) and in the solid state (13–26%). Because of an excellent and reversible pH induced fluorescence quenching/recovery, sensing devices such as fluorescent papers and complex inkjet-printed patterns are successfully fabricated for the detection of volatile acids both in solution and in a vapor atmosphere.


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