Pyrene fluorophores bearing two carbonyl groups in 1,2- positions: Synthesis and photophysical properties of pyrene-1,2-dicarboximides and a pyrene-1,2-dicarboxamide

2016 ◽  
Vol 330 ◽  
pp. 15-21 ◽  
Author(s):  
Anna Wrona-Piotrowicz ◽  
Magdalena Ciechańska ◽  
Janusz Zakrzewski ◽  
Anna Makal
Keyword(s):  
Photophysical Properties ◽  
Carbonyl Groups

scholarly journals Carbonyl-to-Alkyne Electron Donation Effects in up to 10-nm-Long, Unimolecular Oligo(p-phenylene ethynylenes)

2021 ◽  
Vol 03 (02) ◽  
pp. 337-345
Author(s):  
Sinu C. Rajappan ◽  
Olav Vestrheim ◽  
Mona Sharafi ◽  
Jianing Li ◽  
Severin T. Schneebeli
Keyword(s):  
Absorption Spectrum ◽  
Exponential Growth ◽  
Photophysical Properties ◽  
Rotational Barrier ◽  
Carbonyl Groups ◽  
Conformational Disorder ◽  
Triple Bonds ◽  
Phenylene Ethynylenes ◽  
Electron Donation

We synthesized some of the longest unimolecular oligo(p-phenylene ethynylenes) (OPEs), which are fully substituted with electron-withdrawing ester groups. An iterative convergent/divergent (a.k.a. iterative exponential growth – IEG) strategy based on Sonogashira couplings was utilized to access these sequence-defined macromolecules with up to 16 repeating units and 32 ester substituents. The carbonyl groups of the ester substituents interact with the triple bonds of the OPEs, leading to (i) unusual, angled triple bonds with increased rotational barrier, (ii) enhanced conformational disorder, and (iii) associated broadening of the UV/Vis absorption spectrum. Our results demonstrate that fully air-stable, unimolecular OPEs with ester groups can readily be accessed with IEG chemistry, providing new macromolecular backbones with unique geometrical, conformational, and photophysical properties.

Controllable photophysical properties and self-assembly of siloxane-poly(amidoamine) dendrimers

2015 ◽  
Vol 17 (40) ◽  
pp. 26783-26789 ◽  
Author(s):  
Hang Lu ◽  
Jie Zhang ◽  
Shengyu Feng
Keyword(s):  
Metal Ions ◽  
Self Assembly ◽  
Photophysical Properties ◽  
The Self ◽  
Carbonyl Groups ◽  
Strong Luminescence ◽  
Coordination Bonds

Siloxane–poly(amidoamine) dendrimers (Si–PAMAM) can emit strong luminescence due to the aggregation of carbonyl groups, induced by N → Si coordination bonds. So the fluorescence of Si–PAMAM could be adjusted by solvents, H+, metal ions, and dendrimer structures. Micron-sized tube were observed in water–methanol due to the self-assembly of Si–PAMAM.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

Tandem Carbon-Radical Peroxidation−Addition to Carbonyl Groups Reaction. A New Synthesis of Steroidal β-Peroxy Lactones

1996 ◽  
Vol 61 (26) ◽  
pp. 9635-9635
Author(s):  
Alicia Boto ◽  
Rosendo Hernández ◽  
Ernesto Suárez ◽  
Carmen Betancor ◽  
María S. Rodríguez
Keyword(s):  
Carbonyl Groups ◽  
New Synthesis

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

Theoretical Framework of 1,3-Thiazolium-5-Thiolates Mesoionic Compounds: Exploring the Nature of Photophysical Properties and Molecular Nonlinearity

2020 ◽  
Author(s):  
Zeyu Liu ◽  
Shugui Hua ◽  
Tian Lu ◽  
Ziqi Tian
Keyword(s):  
Optical Properties ◽  
Rational Design ◽  
Rayleigh Scattering ◽  
Function Analysis ◽  
Theoretical Calculations ◽  
Photophysical Properties ◽  
Optical Nonlinearity ◽  
Nonlinear Properties ◽  
Photoelectric Performance ◽  
Wave Function Analysis

Inspired by a previous experimental study on the first-order hyperpolarizabilities of 1,3-thiazolium-5-thiolates mesoionic compounds using Hyper-Rayleigh scattering technique, we theoretically investigated the UV-Vis absorption spectra and every order polarizabilities of these mesoionic molecules. Based on the fact that the photophysical and nonlinear properties observed in the experiment can be perfectly replicated, our theoretical calculations explored the essential characteristics of the optical properties of the mesoionic compounds with different electron-donating groups at the level of electronic structures through various wave function analysis methods. The influence of the electron-donating ability of the donor on the optical properties of the molecules and the contribution of the mesoionic ring moiety to their optical nonlinearity are clarified, which have not been reported by any research so far. This work will help people understand the nature of optical properties of mesoionic-based molecules and provide guidance for the rational design of molecules with excellent photoelectric performance in the future.

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