1,721,017 research outputs found
PKA DETERMINATION OF THE DEOXYDINUCLEOTIDE MONOPHOSPHATE CA AND OF THE CORRESPONDING HEXANUCLEOTIDE CACACA BY INVERSE-DETECTED C-13 NMR
No full textThe pK(a) values of adenine N1 and cytosine N3 in the non-self complementary title compounds have been measured by C-13 NMR, using an inverse probe. in the deoxydinucleotide adenine N1 has pK(a) = 2.52, markedly smaller than that of cytosine N3 for which pK(a) = 4.42. In the hexanucleotide the pK(a) values of adenine N1 and cytosine N3 are much closer, being 3.97 and 4.67, respectively
Polyfunetionalized 1(2H)-hexahydropentalenones by rearrangement of bicyelie 1,2-oxazine N-oxide derivatives
No full textOligothiophene-S,S-dioxides: A new class of thiophene-based materials
No full textWe report here that bissilylated oligothiophenes may be selectively oxidized at the thienyl sulfurs by m-chloroperbenzoic acid (m-CPBA) to afford stable S,S-dioxides having alternate aromatic and nonaromatic moieties. These compounds are characterized by enhanced electron delocalization, smaller optical gap, and greater electron affinity than the “fully aromatic” precursors
Thiophene S-oxides: Orbital energies and electrochemical properties
No full textAb initio calculations and experimental oxidation and reduction potentials show that the functionalization of thiophene to the corresponding S-oxide leads to only a minor change in ionization potential but to a dramatic increase in the electron affinity
Polymer-based electrochromic devices-I. Poly(3-methylthiophenes)
No full textThe basic aspects of electrochromism induced by a p-doping/undoping process of conjugated polymers are briefly described. The most important requisites for an electrochromic device are discussed, and polymer electrochromic performance data as well as the test results of a polymer-based variable light transmission electrochromic device are reported. The colour contrast control of conjugated polymers by "tailoring" their conjugation length is discussed and spectroelectrochemical data of poly(3-methylthiophenes) electrosynthesized from 3-methylthiophene isomeric dimers and isomeric tetramers are reported. © 1992
Electrochemical and optical properties of poly(3-methylthiophenes) electrosynthesized by 3,3′-, 3,4′- and 4,4′-dimethyl-2,2′-bithiophenes
No full textThe 3,3′-, 3,4′- and 4,4′-dimethyl-2,2′-bithiophenes, prepared in very pure form and characterized by 13C NMR, were used as starting molecules for electrochemical polymerization of poly(3-methylthiophenes). The optical properties of the resulting polymers were interpreted on the basis of the conformation of the starting dimers determined by force field MMP2 calculations. © 1992
Electrochemical and optical properties of poly (3 -methylthiophenes) electrosynthesized by 3,3'-, 3,4'- and 4,4'-dimethyl-2,2'-bithiophene
No full text3,3'-, 3,4'- and 4,4'-dimethyl-2,2'-bithiophene are used as starting molecules for electrochemical polymerization of poly(3-methylthiophenes). The resulting polymers show different optical properties, interpreted on the basis of the conformation of the starting dimers determined by force field MMP2 calculations. © 1993, Taylor & Francis Group, LLC. All rights reserved
Synthesis and Applications of Thiophene Derivatives as Organic Materials
No full textThiophene-based compounds have acquired increasing importance in materials science and technology, owing to their multiple functional properties, chemical robustness, and versatility. Research studies involving thiophene-based materials are highly interdisciplinary and range from organic electronics, in which the semiconducting properties of these materials are exploited in devices such as thin film field-effect transistors and solar cells, to bioimaging, in which their optical properties are exploited to monitor biological events involving proteins and DNA. Since all fields are concerned with the synthesis of new molecular structures, this chapter also deals with the most recent advances in the synthesis of oligo- and polythiophenes
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