Synthesis of an azobenzene-linker-conjugate with tetrahedrical shape

Zarwell, Sebastian; Rück‐Braun, K.

doi:10.1016/j.tetlet.2008.04.086

Cited by 34 publications

(37 citation statements)

References 30 publications

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“…[25] The nitrosoarenes are obtained by oxidation of aniline derivatives with responding azobenzenes by condensation with the respective aniline derivative in acetic acid. [26] In general, 4-[(trimethylsilyl)ethynyl]aniline (19), which is synthesized by Sonogashira reaction of 4-iodoaniline (17) and (trimethylsilyl)acetylene (18), [28] is used for the reaction with the corresponding nitrosoarene. However, oxidation of compound 19 to the nitroso derivative 33 is also appropriate, even though the yields are low.…”

Section: Syntheses Of Functionalized Triazatriangulenesmentioning

confidence: 99%

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Synthesis of Functionalized Triazatriangulenes for Application in Photo‐Switchable Self‐Assembled Monolayers

2010

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Section: Syntheses Of Functionalized Triazatriangulenesmentioning

confidence: 99%

“…[16] Another promising approach is the use of tripodal linker systems. [17][18][19][20][21][22] These linkers include three thiol groups for the fixation to the surface and cover a surface area that is sufficient to allow the conformational switching of the azobenzene function.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Functionalized Triazatriangulenes for Application in Photo‐Switchable Self‐Assembled Monolayers

2010

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“…Nucleophilic addition of pyridazine 7 to spirocyclopropene 6 using the cyclopropene route [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] (see Scheme 2) in dry ethereal solution at room temperature under dry nitrogen in the absence of light (TLC-controlled using CH 2 Cl 2 as eluent) led to the formation of the photochromic dihydroindolizine (DHI) 9 in low yield (26%). The reaction occurs through the electrophilic addition of the electrondeficient spirocyclopropenes 6 tothe nitrogen of the Nheterocyclic pyridazine 7 which led to ring opening via a cyclopropyl-allyl conversion 8 to the colored betaines 8.…”

Section: Different Attempts For Synthesis Of the Photochromic Dihydromentioning

confidence: 99%

“…Another successful alternative method for the synthesis of the target photochromic DHI 9 was achieved through the following multistep synthesis (see Scheme 3). The Sonogashira coupling of dimethyl 2,7-dibromo-4a Hspiro[fluorene-9,5 -pyrrolo[1,2-b]pyridazine]-6 ,7 -dicarboxylate which was previously prepared by us [10][11][12][13] with trimethylsilylacetylene in presence of palladiumcatalyzed reaction (5%) and CuI/Et 2 N in T = dry THI for 12 hours [29,30] yielded the desired product dimethyl 2,7-bis((trimethylsilyl)ethynyl)-4a H-spiro[fluorene-9,5 -pyrrolo [1,2-b]pyridazine]-6 ,7 -dicarboxylate 11 in 34% yield after purification by flash chromatography on silica gel and CH 2 Cl 2 as eluent. Treatment of DHI 11 with tetrabutyl ammonium fluoride (TBAF) in dry THF for 17 hours afforded the trimethylsilylated product 9 in 68% yield.…”

Section: Different Attempts For Synthesis Of the Photochromic Dihydromentioning

confidence: 99%

“…In these systems, the changes in the electronic patterns responsible for the changes in color also result in variations in other practical physical properties such as luminescence [3], electronic conductance [4,5], refractive index [6], optical rotation [7], and viscosity [8,9]. These materials, based on the 1,5-electrocyclization between two distinct isomeric states: ring-opening form (betaine-form) and ring-closed form (DHI-form), are promising candidates for optical storage media and electronic devices [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

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Photochromism of Dihydroindolizines Part XI: Synthesis of Novel Carbon-Rich Photochromic Dihydroindolizines-Based Potential Electronic Devices

Ahmed

2008

Research Letters in Organic Chemistry

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Recommended by Cyril ParkanyiNovel carbon-rich photochromic dihydroindolizine (DHI) derivatives substituted in the fluorene part (region A) in addition to the new spirocyclopropene 6 have been synthesized. The synthesis of dimethyl 2 ,7 -diethynylspiro[cycloprop[2]ene-1,9 -fluorene]-2,3-dicarboxylate precursor 6 was accomplished in five steps, starting with the literature known conversion of fluorene to 2,7-dibromo-9H-fluoren-9-one in 56% yield over three steps. The chemical structures of the new synthesized materials have been elucidated by both analytical and spectroscopic tools. Three alterative synthetic pathways for the synthesis of DHI 9 have been established.

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Photochromic Responses in Polymer Matrices

Ramachandran

Urban

2011

Handbook of Stimuli‐Responsive Materials

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IntroductionMany concepts of photochromic systems have been inspired by nature. An illustrative example is the reversible shape changes of the photoreceptor molecule rhodopsin in eyes that produces a cascade of molecular rearrangements responding to light illumination [1]. Upon photoexcitation, all-trans retinal undergoes isomerization to 11-cis across the double bond, thus causing shape changes. Although this event occurs at the angstrom (Å) level, there are many molecular interconnected events and responses that are not fully understood. Similar processes have been observed in certain molecules in materials chemistry, although on a much smaller and at a less-orchestrated scale. These are known as photochromic molecules, which were discovered over 150 years ago in an organic crystal of tetracene, and later on, in inorganic and organometallic materials [2][3][4]. In spite of a long research history, a quest for new photochromic materials continues. Color changes induced by ultraviolet (UV) radiation caused by trans − − cis isomerization, ring opening-closing reactions, inter-or intramolecular charge transfer, or bimolecular cycloaddition reactions are of particular interest. To make use of their photochromic behavior in various applications, photochromic entities are often incorporated into polymer matrices.While creating individual molecules and understanding their electronic properties facilitated further advances in understanding molecular mechanisms governing photochromism, useful applications require fabrication into films, sheets, fibers, or beads. This is typically achieved by incorporating photochromic molecules into macromolecular matrices by doping or dispersing, or covalently attaching them onto a polymer backbone. Since photoisomerization of chromophores alter equilibrium conformations, the dimensions of the surrounding polymer matrix play an essential role in spatial rearrangements. The dimensional classifications of the matrix effect have been extensively examined [5], with notable applications in ophthalmic lens, optical storage media, photosensors, and biomedical devices. Furthermore, the kinetics of conformational changes of polymers with photochromic moieties depends upon their physical or chemical incorporation into the matrix [6]. As one Handbook of Stimuli-Responsive Materials. Edited by Marek W. Urban

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Synthesis of an azobenzene-linker-conjugate with tetrahedrical shape

Cited by 34 publications

References 30 publications

Synthesis of Functionalized Triazatriangulenes for Application in Photo‐Switchable Self‐Assembled Monolayers

Synthesis of Functionalized Triazatriangulenes for Application in Photo‐Switchable Self‐Assembled Monolayers

Photochromism of Dihydroindolizines Part XI: Synthesis of Novel Carbon-Rich Photochromic Dihydroindolizines-Based Potential Electronic Devices

Photochromic Responses in Polymer Matrices

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