ChemInform Abstract: Formation and Electronic Properties of Ring-Oxidized and Ring-Reduced Radical Species of the Phthalocyanines and Porphyrins

ChemInform ◽  
2010 ◽  
Vol 31 (36) ◽  
pp. no-no
Author(s):  
Martin Stillman
Keyword(s):  
Electronic Properties ◽  
Radical Species

scholarly journals A general arene C–H functionalization strategy via electron donor-acceptor complex photoactivation

2021 ◽  
Author(s):  
Abhishek Dewanji ◽  
Leendert van Dalsen ◽  
James Rossi-Ashton ◽  
Eloise Gasson ◽  
Giacomo Crisenza ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Electron Donor ◽  
Late Stage ◽  
Aryl Halide ◽  
Aryl Radical ◽  
Sulfonium Salt ◽  
Radical Species ◽  
Metal Free ◽  
Donor Acceptor ◽  
Site Selective

The photoactivation of electron donor-acceptor (EDA) complexes has emerged as a sustainable, selective and versa-tile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical for-mation. Our study introduces triarylsulfonium salts as acceptors in photoactive EDA-complexes, used in combina-tion with catalytic amounts of newly-designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aro-matic compounds by C–H sulfenylation. Using this general, site-selective aromatic C–H functionalization approach, we have developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.

scholarly journals Synthesis, Physical Properties, and Reactivity of Stable, π-Conjugated, Carbon-Centered Radicals

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 665 ◽  
Author(s):  
Takashi Kubo
Keyword(s):  
Physical Properties ◽  
Electronic Properties ◽  
Molecular Orbitals ◽  
Organic Radicals ◽  
Organic Radical ◽  
Radical Species ◽  
Magnetic Spin ◽  
Singly Occupied Molecular Orbitals ◽  
Triarylmethyl Radicals

Recently, long-lived, organic radical species have attracted much attention from chemists and material scientists because of their unique electronic properties derived from their magnetic spin and singly occupied molecular orbitals. Most stable and persistent organic radicals are heteroatom-centered radicals, whereas carbon-centered radicals are generally very reactive and therefore have had limited applications. Because the physical properties of carbon-centered radicals depend predominantly on the topology of the π-electron array, the development of new carbon-centered radicals is key to new basic molecular skeletons that promise novel and diverse applications of spin materials. This account summarizes our recent studies on the development of novel carbon-centered radicals, including phenalenyl, fluorenyl, and triarylmethyl radicals.

Formation and electronic properties of ring-oxidized and ring-reduced radical species of the phthalocyanines and porphyrins

2000 ◽  
Vol 04 (04) ◽  
pp. 374-376 ◽  
Author(s):  
Martin Stillman
Keyword(s):  
Electronic Properties ◽  
Anion Radical ◽  
Electrochemical Techniques ◽  
Solvent Polarity ◽  
Spectroscopic Properties ◽  
Central Metal ◽  
Radical Species ◽  
Redox States ◽  
Intermolecular Association ◽  
Ring Oxidation

The 18-π electron ring in the phthalocyanines and porphyrins largely controls their chemical and spectroscopic properties. It is the aim of this microsymposium to explore the formation and reactivities and the spectroscopic and theoretical properties of the ring-oxidized and ring-reduced phthalocyanines and porphyrins, essentially the π cation and π anion radical species. Redox chemistry of the ring, through ring oxidation and reduction to the radical species, offers powerful, new synthetic capabilities in which photochemical as well as electrochemical techniques may be used to effect highly localized reactions. The chemistry of these radical species can be moderated by control of the redox states of the central metal, the addition of electron-withdrawing or electron-donating peripheral substituents, and by the extent of intermolecular association applying both solvent polarity and peripheral substitution.

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.

Electronic properties of two coupled Siδ-doped GaAs structures

2002 ◽  
Vol 21 (2) ◽  
pp. 91-95 ◽  
Author(s):  
E. Ozturk ◽  
H. Sari ◽  
Y. Ergun ◽  
I. Sokmen
Keyword(s):  
Electronic Properties
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