Structure Property Analysis of the Solution and Solid-State Properties of Bistable Photochromic Hydrazones

2019 ◽  
Author(s):  
Baihao Shao ◽  
Hai Qian ◽  
Quan Li ◽  
ivan aprahamian
Keyword(s):  
Solid State ◽  
Phenyl Group ◽  
Quantum Yields ◽  
Structure Property ◽  
Pull System ◽  
X Ray Crystallography ◽  
Fluorescence Quantum Yields ◽  
Property Analysis ◽  
Fluorescence Characteristics ◽  
Almost All

The development of new photochromic compounds, and the optimization of their photophysical and switching properties are prerequisites for accessing new functions and opportunities that are not possible with currently available systems. To this end we recently developed a new bistable hydrazone switch that undergoes efficient photoswitching and emission ON/OFF toggling in both solution and solid-state. Here, we present a systematic structure-property analysis using a family of hydrazones, and show how their properties, including activation wavelengths, photostationary states (PSSs), photoisomerization quantum yields, thermal half-lives (<i>t</i><sub>1/2</sub>), and solution/solid-state fluorescence characteristics vary as a function of electron donating (EDG) and/or withdrawing (EWG) substituents. These studies resulted in the red-shifting of the absorption profiles of the <i>Z</i> and <i>E</i> isomers of the switches, while maintaining excellent PSSs in almost all of the compounds. The introduction of <i>para</i>-NMe<sub>2</sub>, and/or <i>para</i>-NO<sub>2</sub> groups improved the photoisomerization quantum yields, and the extremely long thermal half-lives (tens to thousands of years) were maintained in most cases, even in a push-pull system, which can be activated solely with visible light. Hydrazones bearing EDGs at the stator phenyl group are an exception and show up to 6 orders of magnitude acceleration in<i>t</i><sub>1/2 </sub>(<i>i.e.</i>, days)<sub> </sub>because of a change in the isomerization mechanism. Moreover, we discovered that a <i>para</i>-NMe<sub>2</sub> group is required to have reasonable fluorescence quantum yields in solution, and that rigidification enhances the emission in the solid-state. Finally, X-ray crystallography analysis showed that the switching process is more efficient in the solid-state when the hydrazone is loosely packed.<br>

Structure Property Analysis of the Solution and Solid-State Properties of Bistable Photochromic Hydrazones

2019 ◽  
Author(s):  
Baihao Shao ◽  
Hai Qian ◽  
Quan Li ◽  
ivan aprahamian
Keyword(s):  
Solid State ◽  
Phenyl Group ◽  
Quantum Yields ◽  
Structure Property ◽  
Pull System ◽  
X Ray Crystallography ◽  
Fluorescence Quantum Yields ◽  
Property Analysis ◽  
Fluorescence Characteristics ◽  
Almost All

The development of new photochromic compounds, and the optimization of their photophysical and switching properties are prerequisites for accessing new functions and opportunities that are not possible with currently available systems. To this end we recently developed a new bistable hydrazone switch that undergoes efficient photoswitching and emission ON/OFF toggling in both solution and solid-state. Here, we present a systematic structure-property analysis using a family of hydrazones, and show how their properties, including activation wavelengths, photostationary states (PSSs), photoisomerization quantum yields, thermal half-lives (<i>t</i><sub>1/2</sub>), and solution/solid-state fluorescence characteristics vary as a function of electron donating (EDG) and/or withdrawing (EWG) substituents. These studies resulted in the red-shifting of the absorption profiles of the <i>Z</i> and <i>E</i> isomers of the switches, while maintaining excellent PSSs in almost all of the compounds. The introduction of <i>para</i>-NMe<sub>2</sub>, and/or <i>para</i>-NO<sub>2</sub> groups improved the photoisomerization quantum yields, and the extremely long thermal half-lives (tens to thousands of years) were maintained in most cases, even in a push-pull system, which can be activated solely with visible light. Hydrazones bearing EDGs at the stator phenyl group are an exception and show up to 6 orders of magnitude acceleration in<i>t</i><sub>1/2 </sub>(<i>i.e.</i>, days)<sub> </sub>because of a change in the isomerization mechanism. Moreover, we discovered that a <i>para</i>-NMe<sub>2</sub> group is required to have reasonable fluorescence quantum yields in solution, and that rigidification enhances the emission in the solid-state. Finally, X-ray crystallography analysis showed that the switching process is more efficient in the solid-state when the hydrazone is loosely packed.<br>

Aza boron-pyridyl-isoindoline isomers: synthesis and photophysical properties

2014 ◽  
Vol 18 (08n09) ◽  
pp. 679-685 ◽  
Author(s):  
Hui Liu ◽  
Yanping Wu ◽  
Zhifang Li ◽  
Hua Lu
Keyword(s):  
Photophysical Properties ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Structure Property ◽  
X Ray ◽  
X Ray Crystallography ◽  
Fluorescence Quantum Yields ◽  
Structure Property Relationships ◽  
New Type ◽  
Vibrational Bands

By changing benzo-fused position on pyridyl unit, three aza boron-pyridyl-isoindoline isomers, a new type of BODIPY analog, are synthesized through a facile two step reaction. These isomers show broad envelopes of intense vibrational bands in the absorption and emission spectra with moderate fluorescence quantum yields. In comparison to those of classical BODIPYs, significant fluorescence intensity are observed for these isomers in film and powder. An analysis of the structure-property relationships has been carried out based on X-ray crystallography, optical spectroscopy, and theoretical calculation.

scholarly journals Remarkable Increase of Fluorescence Quantum Efficiency by Cyano Substitution on an ESIPT Molecule 2-(2-Hydroxyphenyl)benzothiazole: A Highly Photoluminescent Liquid Crystal Dopant

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1105
Author(s):  
Tsuneaki Sakurai ◽  
Masaya Kobayashi ◽  
Hiroyuki Yoshida ◽  
Masaki Shimizu
Keyword(s):  
Liquid Crystal ◽  
Excited State ◽  
Solid State ◽  
Room Temperature ◽  
Cyano Group ◽  
Stokes Shift ◽  
Phenyl Group ◽  
Intramolecular Proton Transfer ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields

Fluorescent molecules with excited-state intramolecular proton transfer (ESIPT) character allow the efficient solid-state luminescence with large Stokes shift that is important for various applications, such as organic electronics, photonics, and bio-imaging fields. However, the lower fluorescence quantum yields (ΦFL) in the solution or viscous media, due to their structural relaxations in the excited state to reach the S0/S1 conical intersection, shackle further applications of ESIPT-active luminophores. Here we report that the introduction of a cyano group (-CN) into the phenyl group of 2-(2-hydroxyphenyl)benzothiazole (HBT), a representative ESIPT compound, remarkably increase its fluorescence quantum yield (ΦFL) from 0.01 (without -CN) to 0.49 (with -CN) in CH2Cl2, without disturbing its high ΦFL (=0.52) in the solid state. The large increase of the solution-state ΦFL of the cyano-substituted HBT (CN-HBT) is remarkable, comparing with our previously reported ΦFL values of 0.05 (with 4-pentylphenyl), 0.07 (with 1-hexynyl), and 0.15 (with 4-pentylphenylethynyl). Of interest, the newly-synthesized compound, CN-HBT, is miscible in a conventional room-temperature nematic liquid crystal (LC), 4-pentyl-4′-cyano biphenyl (5CB), up to 1 wt% (~1 mol%), and exhibits a large ΦFL of 0.57 in the viscous LC medium. A similar ΦFL value of ΦFL = 0.53 was also recorded in another room-temperature LC, trans-4-(4-pentylcyclohexyl)benzonitrile (PCH5), with a doping ratio of 0.5 wt% (~0.5 mol%). These 5CB/CN-HBT and PCH5/CN-HBT mixtures serve as light-emitting room-temperature LCs, and show anisotropic fluorescence with the dichroic ratio of 3.1 upon polarized excitation, as well as electric field response of luminescence intensity changes.

scholarly journals Structure–property relationships in aromatic thioethers featuring aggregation-induced emission: solid-state structures and theoretical analysis

CrystEngComm ◽  
2019 ◽  
Vol 21 (19) ◽  
pp. 3097-3105 ◽  
Author(s):  
Marco Saccone ◽  
Steffen Riebe ◽  
Jacqueline Stelzer ◽  
Christoph Wölper ◽  
Constantin G. Daniliuc ◽  
...  
Keyword(s):  
Solid State ◽  
Theoretical Analysis ◽  
Quantum Yields ◽  
Structure Property ◽  
Aggregation Induced Emission ◽  
Π Interactions ◽  
Fluorescence Quantum Yields ◽  
Structure Property Relationships ◽  
Solid State Structures

The evolution of the fluorescence quantum yields was correlated with the increase of C–H⋯π and the decrease of π⋯π interactions in the solid state.

scholarly journals Indenopyrans – synthesis and photoluminescence properties

2016 ◽  
Vol 12 ◽  
pp. 825-834 ◽  
Author(s):  
Andreea Petronela Diac ◽  
Ana-Maria Ţepeş ◽  
Albert Soran ◽  
Ion Grosu ◽  
Anamaria Terec ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Band ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Band Broadening ◽  
Photoluminescence Properties ◽  
Fluorescence Quantum Yields ◽  
Blue Emitters ◽  
Solid State Fluorescence

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.

scholarly journals Towards Blue AIE/AIEE: Synthesis and Applications in OLEDs of Tetra-/Triphenylethenyl Substituted 9,9-Dimethylacridine Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 445 ◽  
Author(s):  
Monika Cekaviciute ◽  
Aina Petrauskaite ◽  
Sohrab Nasiri ◽  
Jurate Simokaitiene ◽  
Dmytro Volyniuk ◽  
...  
Keyword(s):  
Solid State ◽  
Quantum Yields ◽  
Yellow Emission ◽  
Blue Color ◽  
Television System ◽  
Fluorescence Quantum Yields ◽  
Deep Blue ◽  
Wide Range ◽  
Cyano Groups ◽  
High Yields

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.

The relative stabilities of PhE(NH-t-Bu)2 and PhE(μ-N-t-Bu)2EPh (E = As, Sb, and Bi): X-ray structures of {Li2[PhAs(N-t-Bu)2]}2 and PhE(μ-N-t-Bu)2EPh (E = Sb, Bi)

2003 ◽  
Vol 81 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Glen G Briand ◽  
Tristram Chivers ◽  
Masood Parvez
Keyword(s):  
Solid State ◽  
Nmr Spectra ◽  
Phenyl Group ◽  
Synthetic Approach ◽  
Relative Stabilities ◽  
X Ray ◽  
X Ray Crystallography ◽  
In Trans ◽  
C Nmr

The reaction of PhECl2 with 2 equiv of LiHN-t-Bu has been studied for the series E = As, Sb, and Bi to determine the effect of the phenyl group on subsequent amine condensation processes. For PhAsCl2, the metathesis product PhAs(NH-t-Bu)2 4 was obtained as a colourless oil. Similar reactions involving PhECl2, where E = Sb or Bi, yielded the cyclodipnict(III)azanes PhE(μ-N-t-Bu)2EPh 5 (E = Sb) and 6 (E = Bi), respectively. Treatment of 4 with 2 equiv of n-BuLi produced the dilithium salt Li2[PhAs(N-t-Bu)2] 7a. Products 4, 5, 6, and 7a were characterized by 1H, 7Li (7a), and 13C NMR spectra, while 5, 6, and 7a were also structurally characterized by X-ray crystallography. Compound 7a is dimeric in the solid state via intermolecular Li···N and η6-Li···Ph interactions. The cyclodipnict(III)azanes 5 and 6 have similar structures, with the exocyclic phenyl groups in trans positions relative to the E2N2 ring. This synthetic approach provides a new route to the four-membered rings RE(μ-N-t-Bu)2ER (E = Sb, Bi) and the first example of a bis(organyl)cyclodibism(III)azane.Key words: arsenic, antimony, bismuth, amides, imides.

The influence of phenylethynyl linkers on the photo-physical properties of metal-free porphyrins

2000 ◽  
Vol 04 (07) ◽  
pp. 669-683 ◽  
Author(s):  
GARY A. BAKER ◽  
FRANK V. BRIGHT ◽  
MICHAEL R. DETTY ◽  
SIDDHARTH PANDEY ◽  
COREY E. STILTS ◽  
...  
Keyword(s):  
Excited State ◽  
Radiative Decay ◽  
Phenyl Group ◽  
Quantum Yields ◽  
Fluorescence Lifetimes ◽  
Strongly Coupled ◽  
Metal Free ◽  
Fluorescence Quantum Yields ◽  
Porphyrin Core ◽  
Absorbance Spectra

Series of 5,10,15,20-tetraarylporphyrins 1 and 5,10,15,20-tetrakis[4-(arylethynyl)phenyl]porphyrins 2 were prepared via condensation of pyrrole with the appropriate benzaldehyde or 4-(arylethynyl)benzaldehyde derivative (3). Condensation of meso-phenyldipyrromethane with mixtures of benzaldehyde and 4-(trimethylsilyl-ethynyl)benzaldehyde gave a separable mixture of mono- (6), bis- (both cis-7 and trans-8) and tris[4-(trimethylsilylethynyl)phenyl]porphyrin (9). Following removal of the trimethylsilyl groups of 6–9, the 4-ethynylphenyl groups of 11–14 were coupled to 1-iodo-3,5-di(trifluoromethyl)benzene with Pd ( OAc )2 to give 15–18 bearing one, two (both cis- and trans-) and three 4-[bis-3,5-(trifluoromethyl)phenylethynyl]phenyl groups respectively. Coupling of 11 and 1-iodo-4-nitrobenzene with Pd ( OAc )2 gave porphyrin 19 with one 4-(4-nitrophenylethynyl)phenyl group. Porphyrin 24 with a p-quinone linked to the porphyrin core via a phenylethynyl group was prepared via similar chemistry. The absorbance spectra, emission maxima, excited-state fluorescence lifetimes, quantum yields of fluorescence, rates of fluorescence and rates of non-radiative decay were measured for each of the porphyrins. Absorbance spectra and emission maxima were nearly identical for all the porphyrins of this study, which suggests that the aryl groups and 4-(arylethynyl)phenyl groups are not strongly coupled to the porphyrin core in these metal-free compounds. Fluorescence quantum yields and rates of radiative decay were larger for porphyrins bearing 4-(arylethynyl)phenyl groups, while excited-state fluorescence lifetimes were somewhat shorter. These effects were additive for each additional 4-(arylethynyl)phenyl group.

Tetra and octa(2,6-di-iso-propylphenoxy)-substituted phthalocyanines: a comparative study among their photophysicochemical properties

2012 ◽  
Vol 16 (01) ◽  
pp. 163-174 ◽  
Author(s):  
Ahmad Tuhl ◽  
Wadzanai Chidawanayika ◽  
Hamada Mohamed Ibrahim ◽  
Nouria Al-Awadi ◽  
Christian Litwinski ◽  
...  
Keyword(s):  
Fine Tuning ◽  
Quantum Yields ◽  
Steric Interaction ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
Derivative Series ◽  
Uv Visible ◽  
Almost All ◽  
Triplet Quantum Yields ◽  
Triplet Lifetime

This work reports on the synthesis of novel metal free, zinc, aluminum, gallium and indium tetra and octa (2,6-di-iso-propylphenoxy)-substituted phthalocyanine derivatives. UV-visible and 1H NMR analyses confirm that a non-planar conformation, adapted by the phenoxy substituents due to steric interaction in both derivative series, perfectly discourage cofacial aggregation. Fluorescence quantum yields vary as a function of the number of substituents on the ring periphery, while the fluorescence lifetimes display no distinct trend. Triplet quantum yields are significantly larger for the tetra 2,6-di-iso-propylphenoxy- substituted derivatives relative to their corresponding octa-substituted species. However there was no overall trend in the triplet lifetime values. For almost all of the phthalocyanine derivatives, singlet oxygen was produced with relatively good quantum yields. This study explores the possibility of fine-tuning their physicochemical properties by simple structural modification.

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