scholarly journals Spectral Properties of Highly Emissive Derivative of Coumarin with N,N-Diethylamino, Nitrile and Tiophenecarbonyl Moieties in Water-Methanol Mixture

2019 ◽  
Vol 29 (6) ◽  
pp. 1393-1399
Author(s):  
Anna Kolbus ◽  
Andrzej Danel ◽  
Danuta Grabka ◽  
Mateusz Kucharek ◽  
Karol Szary
Keyword(s):  
Quantum Yield ◽  
Fluorescence Lifetime ◽  
Spectral Properties ◽  
Density Functional ◽  
Photophysical Properties ◽  
Functional Theory ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
Methanol Mixture ◽  
Michael Type Addition

AbstractThe new derivative of coumarin (E)-3-[7-(diethyloamino)-2-oxo-chromen-3yl]-2-(tiophene-2-carbonyl)prop-2-enenitrile (NOSQ) was easy synthesized with commercial substrates as a result of the search of new Michael type addition sensors based on coumarins. Spectral properties of highly emissive NOSQ were investigated by steady state analysis (absorption and fluorescence measurements) and time-resolved analysis (fluorescence lifetime measurements). The effect of water-methanol mixture on the photophysical properties of the NOSQ molecule was analyzed. With increasing of volumetric fraction of water the intensity of absorbance and fluorescence was strongly reduced. The NOSQ quantum yield in methanol was quite high and the first portions of water caused a significant increase in this value. Water, which is usually a quencher, in this case caused the increase in the quantum yield. The fluorescence lifetimes had second-order decay and the values of fluorescence lifetime increased with increasing alcohol content. Density functional theory (DFT) calculations and experimental data remained in agreement and showed that the interaction between the NOSQ molecule and the solvent affects the appearance of the new conformer.

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 Phenyl-Linked Anthracene-Based Macrocycles with Geometrically Tunable Optical Properties

2020 ◽  
Vol 02 (04) ◽  
pp. 336-341
Author(s):  
Ming-Guang Rong ◽  
Junting Wang ◽  
Kam-Hung Low ◽  
Junzhi Liu
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Photophysical Properties ◽  
Density Functional Theory Calculations ◽  
Crystallographic Analysis ◽  
Structural Isomers ◽  
Functional Theory ◽  
Time Resolved ◽  
Tunable Optical Properties ◽  
Photochemical Properties

Anthracene has been widely explored because of its intrinsic photophysical and photochemical properties. Here, two novel anthracene-based macrocycles (1 and 2) were designed and synthesized with para- and meta-phenylene spacers. X-ray crystallographic analysis demonstrates that compound 1 with para-phenylene spacers adopts a nearly planar structure, while compound 2 with meta-phenylene spacers displays a V-shaped geometry. The photophysical properties of the resultant macrocycles, which are structural isomers, are well studied using photoluminescence spectra and time-resolved absorption spectra, which are further corroborated by density functional theory calculations. The optical properties of these two novel macrocycles can be finely tuned via their geometries.

Photophysical Properties of N-Methyl and N-Acetyl Substituted Alloxazine: A Theoretical Investigation

2021 ◽  
Author(s):  
Huimin Guo ◽  
Xiaolin Ma ◽  
Zhiwen Lei ◽  
Yang Qiu ◽  
Bernhard Dick ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Photophysical Properties ◽  
Time Dependent ◽  
Functional Theory ◽  
Td Dft ◽  
Dependent Density

The electronic structure and photophysical properties of a series of N-Methyl and N-Acetyl substituted alloxazine (AZs) were investigated with extensive density functional theory (DFT) and time-dependent density functional theory (TD-DFT)...

scholarly journals Ground- and excited-state characteristics in photovoltaic polymer N2200

RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Steady State ◽  
Excited States ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Time Resolved ◽  
Dependent Density

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.

Anthracene Based AIE Active Probe for Colorimetric and Fluorimetric Detection of Cu2+ Ions

2019 ◽  
Vol 233 (7) ◽  
pp. 895-911 ◽  
Author(s):  
Abdullah G. Al-Sehemi ◽  
Ahmad Irfan ◽  
Mehboobali Pannipara ◽  
Mohammed A. Assiri ◽  
Abul Kalam
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Photophysical Properties ◽  
Functional Theory ◽  
Water Fraction ◽  
Cu Complex ◽  
Active Probe ◽  
And Function ◽  
Intra Molecular Charge Transfer ◽  
Metal Charge Transfer

Abstract A novel aggregation induced emission (AIE) active anthracene based dihydroquinazolinone derivative (probe 1) has been synthesized and characterized by means of spectroscopic methods. The photophysical properties of this probe have been investigated in solvents of different polarity display that fluorescence states are of intramolecular charge transfer (ICT) character. Probe 1 show clear AIE behavior in water/THF mixture on reaching water fraction 95%. The AIE behavior of probe 1 have been exploited for the detection of metal ions in aqueous solution which reveals high selectivity and sensitivity towards Cu2+ ions by colorimetrically and function as a chemosensor in a remarkable turn-off fluorescence manner. Further, the experimental results were investigated by computational means by optimizing the ground state geometries of probe 1 and probe 1-Cu complex using density functional theory (DFT) at B3LYP/6-31G∗∗ and B3LYP/6-31G∗∗(LANL2DZ) levels of theory. Intra-molecular charge transfer was observed in probe 1 while ligand to metal charge transfer (LMCT) for probe 1-Cu complex.

Sign in / Sign up

Export Citation Format

Share Document