Fundamental photoluminescence properties of pyrene carbonyl compounds through absolute fluorescence quantum yield measurement and density functional theory

Tetrahedron ◽  
2012 ◽  
Vol 68 (31) ◽  
pp. 6177-6185 ◽  
Author(s):  
Yosuke Niko ◽  
Yuki Hiroshige ◽  
Susumu Kawauchi ◽  
Gen-ichi Konishi
Keyword(s):  
Density Functional Theory ◽  
Quantum Yield ◽  
Carbonyl Compounds ◽  
Fluorescence Quantum Yield ◽  
Density Functional ◽  
Photoluminescence Properties ◽  
Functional Theory ◽  
Yield Measurement ◽  
Absolute Fluorescence

The Photoluminescence Properties of the Alkali Metals Functionalized Adamantane Studied by Using Linear-Response Time-Dependent Density Functional Theory (TD-DFT) Calculations

2015 ◽  
Vol 1131 ◽  
pp. 117-122
Author(s):  
Nikorn Shinsuphan ◽  
Sriprajak Krongsuk ◽  
Vittaya Amornkitbamrung
Keyword(s):  
Density Functional Theory ◽  
Alkali Metal ◽  
Density Functional ◽  
Stokes Shift ◽  
Time Dependent ◽  
Photoluminescence Properties ◽  
Functional Theory ◽  
Absorption And Emission ◽  
Td Dft ◽  
Dependent Density

The photoluminescence properties of pristine adamantane molecule have been calculated by time-dependent density functional theory (TD-DFT) within the hybrid functional level. This study aims to investigate the luminescence properties of the pristine adamantane molecule and its functionalized with neutral and ion of alkali metal to form C10H16-nXn structure (where X is Li, Li+, Na and Na+ atoms, n=1). The electronic gap of the pristine adamantane (7.15 eV) is too wide, leading to an insulator property. While all the functionalized adamantanes exhibit semiconducting behavior. The absorption and emission energies of the original structure are 6.51 eV and 5.63 eV, respectively which are in good agreement with experimental results. The pure adamantane exhibits a broad photoluminescence peak in the ultraviolet region (UV). The Stokes shift of the transition between vertical and emission is 0.88 eV which agrees well with the previous work that measures the Stokes shift of 0.7 eV. The modification of adamantane indicates that the absorption and emission gaps substantially decreases. Substituting with alkali metal causes the photoluminescence onset can be shifted from the UV to the near-IR region. These results suggest that pure and the alkali metal functionalized adamantane molecules are promoting as candidate materials for the opto-electronic applications in the ultraviolet to infrared spectral regions.

scholarly journals Combustion behaviors of hydrogenated and unhydrogenated colophony esters/petroleum resins using TG-FTIR and DFT analysis

2021 ◽  
Author(s):  
Dan Zhou ◽  
Xiaopeng Chen ◽  
Jiezhen Liang ◽  
Xiaojie Wei ◽  
Chenghong Wu ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Dft Calculations ◽  
Carbonyl Compounds ◽  
Density Functional ◽  
Functional Theory ◽  
Master Plots ◽  
Glycerol Ester ◽  
Friedman Method ◽  
Combustion Behaviors

The combustion behavior of tackifying resins (such as glycerol ester of colophony/hydrogenated colophony and C9/hydrogenated C9 petroleum resin, namely GEC, GEHC, C9PR and HC9PR, respectively) were investigated using TG-FTIR and density functional theory (DFT) analyses. Results from combustion characteristics indicate tackifying resins and their wastes are a promising fuel for generating energy. The average activation energies obtained by Friedman method for GEC, GEHC, C9PR and HC9PR were 223.51, 162.16, 166.52 and 116.20 kJ/mol, respectively, revealing that (H)C9PR were more readily combustible than GE(H)C, and their hydrogenated products burned more easily than their unhydrogenated ones, which were strongly supported by the TG-FTIR results. DFT calculations also show that the bond dissociation energy of C-C bond of GEC is higher than those of C9PR and GEHC. The best appropriate reaction mechanism evaluated by integral master plots is f(α)=3(1-α)2/3. Volatiles are mainly composed of H2O, CH4, CO2, CO, alcohol, aromatic and carbonyl compounds.

scholarly journals The Phospha-Bora-Wittig Reaction

2021 ◽  
Author(s):  
Andryj Borys ◽  
Ella Rice ◽  
Gary Nichol ◽  
Michael Cowley
Keyword(s):  
Density Functional Theory ◽  
Lewis Acid ◽  
Carbonyl Compounds ◽  
Density Functional ◽  
Wittig Reaction ◽  
Acid Base ◽  
Functional Theory ◽  
Direct Preparation ◽  
Wittig Reactions

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

scholarly journals Novel Dicyano-Phenylenevinylene Fluorophores for Low-Doped Layers: A Highly Emissive Material for Red OLEDs

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1751 ◽  
Author(s):  
Rosita Diana ◽  
Barbara Panunzi ◽  
Francesco Marrafino ◽  
Stefano Piotto ◽  
Ugo Caruso
Keyword(s):  
Density Functional Theory ◽  
Fluorescence Quantum Yield ◽  
Density Functional ◽  
Spectroscopic Properties ◽  
Functional Theory ◽  
Light Emitting ◽  
Organic Light ◽  
Red Oleds ◽  
Feasibility Test ◽  
Luminescence Performance

Two efficient deep red (DR)-emitting organic dicyano-phenylenevinylene derivatives with terminal withdrawing or donor groups were synthesized. The spectroscopic properties of the neat solids and the low-doped layers in polystyrene or polyvinylcarbazole host matrixes were analyzed, and the luminescence performance was explained using density functional theory (DFT) analysis. A noteworthy 89% fluorescence quantum yield was observed for the brightest red-emissive polyvinylcarbazole (PVK) blend. This result pushed us to successfully produce an emissive red organic light-emitting device (OLED) as a preliminary feasibility test.

scholarly journals Photochemical α-Cleavage Reaction of 3’,5’-Dimethoxybenzoin: A Combined Time-Resolved Spectroscopy and Computational Chemistry Study

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3548
Author(s):  
Yuanchun Li ◽  
Xiting Zhang ◽  
Zhiping Yan ◽  
Lili Du ◽  
Wenjian Tang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Quantum Yield ◽  
Dft Calculations ◽  
Density Functional ◽  
Transient Absorption ◽  
Type I ◽  
Functional Theory ◽  
Time Resolved ◽  
Norrish Type ◽  
Intramolecular Hydrogen

Benzoin is one of the most commonly used photoinitiators to induce free radical polymerization. Here, improved benzoin properties could be accomplished by the introduction of two methoxy substituents, leading to the formation of 3’,5’-dimethoxybenzoin (DMB) which has a higher photo-cleavage quantum yield (0.54) than benzoin (0.35). To elucidate the underlying reaction mechanisms of DMB and obtain direct information of the transient species involved, femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopic experiments in conjunction with density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were performed. It was found that the photo-induced α-cleavage (Norrish Type I reaction) of DMB occurred from the nπ* triplet state after a rapid intersystem crossing (ISC) process (7.6 ps), leading to the generation of phenyl radicals on the picosecond time scale. Compared with Benzoin, DMB possesses two methoxy groups which are able to stabilize the alcohol radical and thus result in a stronger driving force for cleavage and a higher quantum yield of photodissociation. Two stable conformations (cis-DMB and trans-DMB) at ground state were found via DFT calculations. The influence of the intramolecular hydrogen bond on the α-cleavage of DMB was elaborated.

scholarly journals The Phospha-Bora-Wittig Reaction

2021 ◽  
Author(s):  
Andryj Borys ◽  
Ella Rice ◽  
Gary Nichol ◽  
Michael Cowley
Keyword(s):  
Density Functional Theory ◽  
Lewis Acid ◽  
Carbonyl Compounds ◽  
Density Functional ◽  
Wittig Reaction ◽  
Acid Base ◽  
Functional Theory ◽  
Direct Preparation ◽  
Wittig Reactions

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

LiOtBu-promoted stereoselective deconjugation of α,β-unsaturated diesters probed using density functional theory

2020 ◽  
Vol 7 (21) ◽  
pp. 3427-3433
Author(s):  
Won Jun Jang ◽  
Seon Bin Song ◽  
Soyeon Lee ◽  
Seok Yeol Yoo ◽  
You Kyoung Chung ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Carbonyl Compounds ◽  
Density Functional ◽  
Functional Theory

We report the isomerisation of α,β-unsaturated diesters to thermodynamically less favourable β,γ-unsaturated carbonyl compounds in the absence of strongly basic anhydrous or photochemical conditions.

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