Synthesis of an azobenzene-linker-conjugate with tetrahedrical shape

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

“…[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.…”

“…[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.…”

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

“…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.…”

“…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.…”

“…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].…”