Violene/Cyanine Hybrids as Electrochromic Systems: A New Variation of the General Structure

Hünig, Siegfried; Langels, Anja; Schmittel, Michael; Wenner, Hermann; Perepichka, Igor F.; Peters, Karl

doi:10.1002/1099-0690(200104)2001:7<1393::aid-ejoc1393>3.0.co;2-z

Cited by 35 publications

(7 citation statements)

References 19 publications

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“…1). 11 Reaction of L with [Cu(MeCN Single crystal X-ray structural determinations ‡ reveal that all six compounds form isotopological three-dimensional frameworks (Fig. 2), crystallising in the highly symmetrical tetragonal space group I4 1 /amd.…”

Section: Reactions Of Tetrahedralmentioning

confidence: 99%

A design strategy for four-connected coordination frameworks

et al. 2004

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Section: Reactions Of Tetrahedralmentioning

confidence: 99%

A design strategy for four-connected coordination frameworks

et al. 2004

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“…Construction of organic molecules that contain multiple redox-active chromophores is fairly important for the preparation of novel polyelectrochromic materials, which respond to different potentials with a variety of colors . Hünig et al recently proposed a concept of a violene−cyanine hybrid to produce a stabilized organic electrochromic system. The hybrid is expected to provide a cyanine dye by an overall two-electron transfer as illustrated by the general structure in Scheme .…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Poly(6-azulenylethynyl)benzene Derivatives as a Multielectron Redox System with Liquid Crystalline Behavior

et al. 2003

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A series of poly(6-azulenylethynyl)benzenes substituted with n-hexyloxycarbonyl chains at 1,3-positions in azulene rings, i.e., hexakis-, 1,2,4,5-tetrakis-, 1,3,5-tris-, and 1,4-bis(6-azulenylethynyl)benzene derivatives 1, 2, 3, and 4b, have been prepared by a simple one-pot reaction involving repeated Pd-catalyzed alkynylation of halogenated arenes with substituted 6-ethynylazulene and/or ethynylated arenes with substituted 6-bromoazulene under Sonogashira-Hagihara conditions. The redox behavior of these novel poly(6-azulenylethynyl)benzene derivatives was examined by cyclic voltammetry (CV), which revealed the presumed multielectron redox properties. Compound 4b exhibited a one-step, two-electron reduction wave upon CV, which revealed the formation of the dianion stabilized by two 6-azulenylethynyl substituents under electrochemical reduction conditions. Four 6-azulenylethynyl substituents on a benzene ring in a 1,2,4,5 relationship increased the electron-accepting properties because of the formation of a stabilized closed-shell dianionic structure, whereas 3 was reduced at more negative reduction potentials. In contrast to the multistep redox behavior of 2, compound 1 was reduced in one step at -1.28 V upon CV. Compound 1 showed a wide temperature range of columnar mesophases (Col(ho) and Col(ro)) from 77.3 degrees C to the decomposition temperature at ca. 270 degrees C. Compounds 2, 3, and 4b exhibited columnar mesomorphism (Col(ro)) with crystalline polymorphs for 2, unusual triple-melting behavior for 3, and both double-melting behavior and columnar mesomorphism (Col(ho)) for 4b. Therefore, the investigated systems exemplify a new principle for multielectron redox behavior with liquid crystalline properties.

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“…However, to date, molecules with potentially useful electronic properties constructed by azulene derivatives are fairly scarce. Recently, Hünig et al have proposed the concept of a violene/cyanine hybrid as stabilized organic electrochromics . The hybrid contains the moieties XC−Y, which represent a “cyanine”-type structure in fully reduced or oxidized form, as end groups of a violene.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Two-Electron Redox Behavior of Diazuleno[2,1-a:1,2-c]naphthalenes

et al. 2002

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The Diels-Alder reaction of di-2-azulenylacetylene with tetraphenylcyclopentadienone afforded 7,8,9,10-tetraphenyldiazuleno[2,1-a:1,2-c]naphthalene in one pot via autoxidation of the presumed 1,2-di-2-azulenylbenzene derivative. In contrast, a similar reaction of bis(1-methoxycarbonyl-2-azulenyl)acetylene with tetraphenylcyclopentadienone gave the 1,2-di-2-azulenylbenzene derivative. The following cyclodehydrogenation reaction of the benzene derivative with iron(III) chloride afforded diazuleno[2,1-a:1,2-c]naphthalene 6,11-bismethoxycarbonyl derivative. The redox behavior of these novel diazuleno[2,1-a:1,2-c]naphthalenes was examined by cyclic voltammetry (CV). These compounds exhibited two-step oxidation waves at +0.22 to +0.71 V upon CV, which revealed the formation of a radical cation and dication stabilized by the fused two azulene rings under the electrochemical oxidation conditions. Since the 1,2-di-2-azulenylbenzene derivative was oxidized at higher oxidation potentials (+0.83 and +1.86 V), the fusion of the two azulene rings to naphthalene increased electron-donating properties because of the formation of a closed-shell dicationic structure. Formation of the radical cation was characterized by UV-vis spectroscopy under the electrochemical oxidation conditions, although no evidence was obtained for the presumed dication under the conditions of the UV-vis spectroscopy measurement.

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Violene/Cyanine Hybrids as Electrochromic Systems: A New Variation of the General Structure

Cited by 35 publications

References 19 publications

A design strategy for four-connected coordination frameworks

A design strategy for four-connected coordination frameworks

Synthesis of Poly(6-azulenylethynyl)benzene Derivatives as a Multielectron Redox System with Liquid Crystalline Behavior

Synthesis and Two-Electron Redox Behavior of Diazuleno[2,1-a:1,2-c]naphthalenes

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