scholarly journals Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

2020 ◽  
Vol 16 ◽  
pp. 895-903 ◽  
Author(s):  
Liliia Moshniaha ◽  
Marika Żyła-Karwowska ◽  
Joanna Cybińska ◽  
Piotr J Chmielewski ◽  
Ludovic Favereau ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Bond Activation ◽  
Reactive Systems ◽  
Quantum Yields ◽  
Luminescent Materials ◽  
Reaction Selectivity ◽  
Circularly Polarized ◽  
Donor Acceptor ◽  
Tandem Cyclization ◽  
First Time

Boomerang-shaped bipyrroles containing donor–acceptor units were obtained through a tandem palladium-mediated reaction consisting of a cyclization step, involving double C–H bond activation, and a double α-oxygenation. The latter reaction can be partly suppressed for the least reactive systems, providing access to α-unsubstituted boomerangs for the first time. These “α-free” systems are highly efficient fluorophores, with emission quantum yields exceeding 80% in toluene. Preliminary measurements show that helicene-like boomerangs may be usable as circularly polarized luminescent materials.

TWO-DIMENSIONAL CIRCULARLY-POLARIZED-LIGHT PHOTOELECTRON DIFFRACTION FOR THE ANALYSIS OF MAGNETIC AND ELECTRONIC PROPERTIES ON SURFACES

2000 ◽  
Vol 07 (05n06) ◽  
pp. 643-647 ◽  
Author(s):  
K. ENOMOTO ◽  
Y. MIYATAKE ◽  
K. FUKUMOTO ◽  
A. KOBAYASHI ◽  
K. HATTORI ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Polarized Light ◽  
Emission Angle ◽  
Two Dimensional ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Photoelectron Diffraction ◽  
Angle Dependence ◽  
First Time ◽  
Good Agreement

Circular dichroism has been measured in the photoelectron diffraction of bulk W 4f photoelectrons from the W(110)(1×1) clean surface. The forward focusing peaks along the symmetric axis in the diffraction pattern showed an azimuthal rotation similar to those reported in a prior experiment on Si(001) and chemically shifted W 4f photoelectrons from the W(110)(1×1)-O surface. The emission angle dependence of the rotation angles has been measured and analyzed for the first time and the angles observed are in good agreement with those calculated using the formula Δ ϕ=m/kR sin 2θ derived previously by Daimon et al. [Jpn. J. Phys.32, L1480 (1993)] considering the angular dependence of m. This property gives a basis for the analysis of structure or various magnetic and electronic properties on surfaces.

Formation and Trapping of the Thermodynamically Unfavoured Inverted-Hemicucurbit[6]uril

2019 ◽  
Author(s):  
Elena Prigorchenko ◽  
Sandra Kaabel ◽  
Triin Narva ◽  
Anastassia Baškir ◽  
Maria Fomitšenko ◽  
...  
Keyword(s):  
Complex Formation ◽  
Combinatorial Chemistry ◽  
Trifluoroacetic Acid ◽  
Chloride Anion ◽  
Binding Affinities ◽  
Dynamic Covalent Chemistry ◽  
Reaction Selectivity ◽  
Low Concentration ◽  
Dynamic Combinatorial Chemistry ◽  
First Time

Amplification of a thermodynamically unfavoured macrocyclic product through the directed shift of the equilibrium between dynamic covalent chemistry library members is difficult to achieve. We show for the first time that during condensation of formaldehyde and <i>cis</i>-<i>N,N'</i>-cyclohexa-1,2-diylurea formation of <i>inverted-cis</i>-cyclohexanohemicucurbit[6]uril (<i>i-cis</i>-cycHC[6]) can be induced at the expense of thermodynamically favoured <i>cis</i>-cyclohexanohemicucurbit[6]uril (<i>cis</i>-cycHC[6]). The formation of <i>i-cis-</i>cycHC[6] is enhanced in low concentration of the templating chloride anion and suppressed in excess of this template. We found that reaction selectivity is governed by the solution-based template-aided dynamic combinatorial chemistry and continuous removal of the formed cycHC[6] macrocycles from the equilibrating solution by precipitation. Notably, the <i>i-cis</i>-cycHC[6] was isolated with 33% yield. Different binding affinities of three diastereomeric <i>i-cis</i>-, <i>cis</i>-cycHC[6] and their chiral isomer (<i>R,R</i>)-cycHC[6] for trifluoroacetic acid demonstrate the influence of macrocycle geometry on complex formation.

Molecular Generation Targeting Desired Electronic Properties via Deep Generative Models

2019 ◽  
Author(s):  
Qi Yuan ◽  
Alejandro Santana-Bonilla ◽  
Martijn Zwijnenburg ◽  
Kim Jelfs
Keyword(s):  
Neural Network ◽  
Electronic Properties ◽  
Transfer Learning ◽  
Recurrent Neural Network ◽  
Chemical Space ◽  
Generative Models ◽  
Molecular Features ◽  
Donor Acceptor ◽  
Homo Lumo ◽  
Training Sets

<p>The chemical space for novel electronic donor-acceptor oligomers with targeted properties was explored using deep generative models and transfer learning. A General Recurrent Neural Network model was trained from the ChEMBL database to generate chemically valid SMILES strings. The parameters of the General Recurrent Neural Network were fine-tuned via transfer learning using the electronic donor-acceptor database from the Computational Material Repository to generate novel donor-acceptor oligomers. Six different transfer learning models were developed with different subsets of the donor-acceptor database as training sets. We concluded that electronic properties such as HOMO-LUMO gaps and dipole moments of the training sets can be learned using the SMILES representation with deep generative models, and that the chemical space of the training sets can be efficiently explored. This approach identified approximately 1700 new molecules that have promising electronic properties (HOMO-LUMO gap <2 eV and dipole moment <2 Debye), 6-times more than in the original database. Amongst the molecular transformations, the deep generative model has learned how to produce novel molecules by trading off between selected atomic substitutions (such as halogenation or methylation) and molecular features such as the spatial extension of the oligomer. The method can be extended as a plausible source of new chemical combinations to effectively explore the chemical space for targeted properties.</p>

Research progress on organic self-assembling low-dimensional circularly polarized luminescent materials

2020 ◽  
Vol 13 (0) ◽  
pp. 1-11
Author(s):  
WANG Meng-Zhu ◽  
◽  
DENG Yong-Jing ◽  
LIU Shu-Juan ◽  
ZHAO Qiang
Keyword(s):  
Research Progress ◽  
Luminescent Materials ◽  
Circularly Polarized ◽  
Self Assembling ◽  
Low Dimensional

An expanded isoindigo unit as a new building block for a conjugated polymer leading to high-performance solar cells

2014 ◽  
Vol 2 (15) ◽  
pp. 5427-5433 ◽  
Author(s):  
Shugang Li ◽  
Zhongcheng Yuan ◽  
Jianyu Yuan ◽  
Ping Deng ◽  
Qing Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Building Block ◽  
Conjugated Polymer ◽  
High Performance ◽  
Fill Factor ◽  
Solar Cell Device ◽  
Donor Acceptor ◽  
First Time

An expanded isoindigo unit (IBTI) has been incorporated into a donor–acceptor conjugated polymer for the first time. The PCE of the solar cell device based on the new polymer reached 6.41% with a fill factor of 0.71.

Electronic properties of an electron donor-acceptor polymer blend

1988 ◽  
Vol 21 (6) ◽  
pp. 1888-1890 ◽  
Author(s):  
Toshiyuki Uryu ◽  
Haruki Ohkawa ◽  
Takashi Furuichi ◽  
Ryuichi Oshima
Keyword(s):  
Electronic Properties ◽  
Polymer Blend ◽  
Electron Donor ◽  
Donor Acceptor

Fused donor–acceptor π-conjugated diazatruxenones: synthesis and electronic properties

2018 ◽  
Vol 5 (11) ◽  
pp. 1748-1755 ◽  
Author(s):  
Angela Benito-Hernández ◽  
Mardia T. El-Sayed ◽  
Juan T. López Navarrete ◽  
M. Carmen Ruiz Delgado ◽  
Berta Gómez-Lor
Keyword(s):  
Charge Transport ◽  
Electronic Properties ◽  
Acceptor Molecule ◽  
Promising Candidate ◽  
Donor Acceptor

A promising candidate for ambipolar charge transport: a disk-like platform, diazatruxenone, as a novel, compact and planar donor–acceptor molecule.

Heteroarray of cobalt(II)tetrasulfophthalocyanine and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin: synthesis, isolation and electronic properties

2012 ◽  
Vol 16 (02) ◽  
pp. 244-249 ◽  
Author(s):  
Thiago T. Tasso ◽  
Wania C. Moreira
Keyword(s):  
Electronic Properties ◽  
Spectroscopic Characterization ◽  
Charge Transfer Process ◽  
Isolation And Purification ◽  
Electronic Densities ◽  
Porphyrin Synthesis ◽  
A Charge ◽  
Job's Method ◽  
First Time

Porphyrin and phthalocyanine macrocycles with ionic substituents can form mixed assemblies with interesting electronic properties for potential application on the development of new devices. This paper reports the synthesis, isolation and purification of heteroaggregate formed by cobalt(II) 4,4′,4″,4‴-tetrasulfophthalocyanine (CoTsPc) and cobalt(II) tetrakis(N-methyl-4-pyridyl)porphyrin (CoTMPyP), followed by its spectroscopic characterization. Spectroscopic titration, performed with a CoTsPc water/acetone solution, allowed the use of Job's method for determination of the heteroaggregates stoichiometry. The Job's plot revealed the formation of only one predominant heterocomplex in solution, containing two CoTsPc molecules in terminal positions and a central CoTMPyP one. For the first time, a method for isolation and purification of a mixed ionic array has been reported in the literature. The triad's electronic spectrum is quite different from the sum of the macrocycles isolated spectra, due to the overlap of their electronic densities and a charge transfer process between CoTsPc and CoTMPyP.

Well-defined star-shaped donor–acceptor conjugated molecules for organic resistive memory devices

2015 ◽  
Vol 51 (75) ◽  
pp. 14179-14182 ◽  
Author(s):  
Hung-Chin Wu ◽  
Jicheng Zhang ◽  
Zhishan Bo ◽  
Wen-Chang Chen
Keyword(s):  
Charge Storage ◽  
Memory Devices ◽  
Resistive Memory ◽  
Conjugated Molecules ◽  
Storage Materials ◽  
End Groups ◽  
Donor Acceptor ◽  
Solution Processable ◽  
First Time

Solution processable star-shaped donor–acceptor conjugated molecules are explored for the first time as charge storage materials for resistor-type memory devices with a triphenylamine (donor) core, and three 1.8-naphthalimide (acceptors) end-groups.

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