TY - JOUR
T1 - Bis[bis-(4-alkoxyphenyl)amino] derivatives of dithienylethene, bithiophene, dithienothiophene and dithienopyrrole
T2 - Palladium-catalysed synthesis and highly delocalised radical cations
AU - Odom, Susan A.
AU - Lancaster, Kelly
AU - Beverina, Luca
AU - Lefler, Kelly M.
AU - Thompson, Natalie J.
AU - Coropceanu, Veaceslav
AU - Bredas, Jean Luc
AU - Marder, Seth R.
AU - Barlow, Stephen
N1 - Funding Information:
The preparation of this chapter and the research of our laboratory reported therein were aided by a grant from the National Institutes of Health (GM-18172).
PY - 2007
Y1 - 2007
N2 - Five diamines with thiophene-based bridges-(E)-1,2-bis-{5-[bis(4- butoxyphenyl)amino]-2-thienyljethylene (1), 5,5′-bis[bis(4-methoxyphenyl) amino]-2,2′-bithiophene (2), 2,6-bis[bis(4-butoxyphenyl)amino]dithieno[3, 2-b:2′,3′-d]thiophene (3), N-(4-tert-butylphenyl)-2,6-bis[bis(4- methoxyphenyl)amino]dithieno[3,2-b:2′,3′-d]pyrrole (4a) and N-tert-butyl-2,6-bis[bis(4-methoxyphenyl)amino]dithieno[3,2-b:2′, 3′-d]pyrrole (4b)-have been synthesised. The syntheses make use of the palladium(0)-catalysed coupling of brominated thiophene species with diarylamines, in some cases accelerated by microwave irradiation. The molecules all undergo facile oxidation, 4b being the most readily oxidised at about -0.4 V versus ferrocenium/ferrocene, and solutions of the corresponding radical cations were generated by addition of tris(4-bromophenyl)aminium hexachloroantimonate to the neutral species. The near-IR spectra of the radical cations show absorptions characteristic of symmetrical delocalised species (that is, class III mixed-valence species); analysis of these absorptions in the framework of Hush theory indicates strong coupling between the two amine redox centres, stronger than that observed in species with phenylenebased bridging groups of comparable length. The strong coupling can be attributed to high-lying orbitais of the thiophene-based bridging units. ESR spectroscopy indicates that the coupling constant to the amino nitrogen atoms is somewhat reduced relative to that in a stilbene-bridged analogue. The neutral species and the corresponding radical cations have been studied with the aid of density functional theory and time-dependent density functional theory. The DFT-calculated ESR parameters are in good agreement with experiment, while calculated spin densities suggest increased bridge character to the oxidation in these species relative to that in comparable species with phenylene-based bridges.
AB - Five diamines with thiophene-based bridges-(E)-1,2-bis-{5-[bis(4- butoxyphenyl)amino]-2-thienyljethylene (1), 5,5′-bis[bis(4-methoxyphenyl) amino]-2,2′-bithiophene (2), 2,6-bis[bis(4-butoxyphenyl)amino]dithieno[3, 2-b:2′,3′-d]thiophene (3), N-(4-tert-butylphenyl)-2,6-bis[bis(4- methoxyphenyl)amino]dithieno[3,2-b:2′,3′-d]pyrrole (4a) and N-tert-butyl-2,6-bis[bis(4-methoxyphenyl)amino]dithieno[3,2-b:2′, 3′-d]pyrrole (4b)-have been synthesised. The syntheses make use of the palladium(0)-catalysed coupling of brominated thiophene species with diarylamines, in some cases accelerated by microwave irradiation. The molecules all undergo facile oxidation, 4b being the most readily oxidised at about -0.4 V versus ferrocenium/ferrocene, and solutions of the corresponding radical cations were generated by addition of tris(4-bromophenyl)aminium hexachloroantimonate to the neutral species. The near-IR spectra of the radical cations show absorptions characteristic of symmetrical delocalised species (that is, class III mixed-valence species); analysis of these absorptions in the framework of Hush theory indicates strong coupling between the two amine redox centres, stronger than that observed in species with phenylenebased bridging groups of comparable length. The strong coupling can be attributed to high-lying orbitais of the thiophene-based bridging units. ESR spectroscopy indicates that the coupling constant to the amino nitrogen atoms is somewhat reduced relative to that in a stilbene-bridged analogue. The neutral species and the corresponding radical cations have been studied with the aid of density functional theory and time-dependent density functional theory. The DFT-calculated ESR parameters are in good agreement with experiment, while calculated spin densities suggest increased bridge character to the oxidation in these species relative to that in comparable species with phenylene-based bridges.
KW - Amination
KW - Electron spin resonance
KW - Mixed-valent compounds
KW - Oxidation
KW - Radicals
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U2 - 10.1002/chem.200700668
DO - 10.1002/chem.200700668
M3 - Article
AN - SCOPUS:36649030994
SN - 0947-6539
VL - 13
SP - 9637
EP - 9646
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 34
ER -