scholarly journals Synthesis and electronic properties of π-extended flavins

2015 ◽  
Vol 13 (40) ◽  
pp. 10198-10204 ◽  
Author(s):  
L. N. Mataranga-Popa ◽  
I. Torje ◽  
T. Ghosh ◽  
M. J. Leitl ◽  
A. Späth ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Quantum Yields ◽  
Violuric Acid ◽  
Aromatic Systems

Three flavins with extended aromatic systems were synthesized in moderate to good yields by condensation of the corresponding amines with violuric acid. The compounds are highly fluorescent, show quantum yields of up to 80% and redox mechanisms similar to riboflavin.

An experimental and theoretical study on the electrostatic effect of an appended cationic group on electronic properties of aromatic systems

2007 ◽  
Vol 9 (45) ◽  
pp. 5988 ◽  
Author(s):  
Viviana Grosso ◽  
Carlos Previtali ◽  
Carlos A. Chesta ◽  
D. Mariano A. Vera ◽  
Adriana B. Pierini
Keyword(s):  
Electronic Properties ◽  
Theoretical Study ◽  
Cationic Group ◽  
Electrostatic Effect ◽  
Aromatic Systems

Synthesis of benzobisoxazole-based D-π-A-π-D organic chromophores with variable optical and electronic properties

2012 ◽  
Vol 84 (4) ◽  
pp. 991-1004 ◽  
Author(s):  
James S. Klimavicz ◽  
Jared F. Mike ◽  
Achala Bhuwalka ◽  
Aimeé L. Tomlinson ◽  
Malika Jeffries-EL
Keyword(s):  
Electronic Properties ◽  
Energy Levels ◽  
Visible Spectrum ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Aryl Aldehydes ◽  
Organic Chromophores ◽  
Optical And Electronic Properties ◽  
High Fluorescence ◽  
Triphenylamine Derivative

A series of symmetrical D-π-A-π-D molecules comprised of benzo[1,2-d;4,5-d']bisoxazole (BBO) and various arylenevinylenes was synthesized via a Knoevenagel condensation of 2,6-dimethyl BBO and the corresponding aryl aldehydes. The resulting compounds had energy levels that were easily modulated and broad absorptions in the visible spectrum. They also demonstrated high fluorescence quantum yields in solution. The solvatochromism of several derivatives was examined in a number of solvents, and it was found that the emission of the triphenylamine derivative varied by almost 100 nm, depending on the polarity of the solvent. Collectively, these results indicate that the optical and electronic properties of benzobisoxazoles are readily tuned through the choice of aryl co-monomer.

Construction of Boron-Containing Aromatic Heterocycles

Synthesis ◽  
2017 ◽  
Vol 49 (14) ◽  
pp. 2985-3034 ◽  
Author(s):  
Rei Kinjo ◽  
Bochao Su
Keyword(s):  
Electronic Properties ◽  
Aromatic Heterocycles ◽  
Recent Developments ◽  
Long Time ◽  
Aromatic Systems

Boron-containing aromatic systems exhibit unique electronic properties and reactivities that have been extensively studied for a long time. This review highlights the recent developments in the synthesis of aromatic boron-containing heterocycles. The organization of the contents is based on the sizes of rings and the heteroatoms other than boron. Early work in the field is briefly introduced, but the main focus is on recent reports published during the period of 2008 through 2016.1 Introduction2 Five-Membered Rings2.1 Borole Derivatives2.2 B,N-Heterocycles2.3 B,O-Heterocycles3 Six-Membered Rings3.1 Borabenzene Derivatives3.2 Boratabenzene Derivatives3.3 1,4-Diborabenzene3.4 B,N-Heterocycles3.5 B,E-Heterocycles (E = O, S, P, Te)4 Three-Membered Rings4.1 Borirenes4.2 Azadiboriridines4.3 Triboracyclopropenyl Dianion5 Four-Membered Rings5.1 bicyclo-Tetraborane(4)5.2 1,3-Diborete5.3 B,E-Heterocycles (E = N, P, As, Sb, Bi, O, S, Se)6 Seven-Membered Rings (Borepines)7 Conclusion and Perspective

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.

Topologische Indices alternierender polycyclischer aromatischer Kohlenwasserstoffe und ihre Korrelationen mit elektronischen Eigenschaften / Topological Indices of Alternant Polycyclic Aromatic Hydrocarbons and their Correlations with Electronic Properties

1981 ◽  
Vol 36 (11) ◽  
pp. 1217-1221
Author(s):  
K.-D. Gundermann ◽  
C. Lohberger ◽  
M. Zander
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Topological Index ◽  
Distance Matrix ◽  
Topological Indices ◽  
Matrix Elements ◽  
Wiener Number ◽  
Polycyclic Aromatic ◽  
Aromatic Systems

The half-sum of the distance matrix elements derived from the characteristic graphs, i.e. the Wiener number of these graphs is proposed as a new topological index for alternant polycyclic aromatic hydrocarbons. It is shown by regression analysis that correlations between topological indices and electronic properties of alternant aromatic systems do only exist for those indices and properties which depend to the same degree from the size of the systems and for which the corresponding relation applies to the topology.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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