- Synthesis of functionalized triazatriangulenes for application in photo- Switchable self-assembled monolayers
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Various triazatriangulenes are synthesized by nucleophilic attack at the central C atom of triazatriangulenium ions. The molecular functions, especially azobenzenes, are fixed via an ethynyl linker by in situ deprotection of trimethylsilylalkynes. The structure of two of these molecules is further investigated by X-ray crystallography. The photo-inducedtrans/cis-isomerization of the azobenzene substituted derivatives is analyzed in solution and shows great promise for the preparation of switchable functionalized monolayers, as the triazatriangulenes are known for their self-assembly on gold surfaces. [1].
- Kubitschke, Jens,Naether, Christian,Herges, Rainer
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scheme or table
p. 5041 - 5055
(2010/11/05)
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- Fluorescent bis(oligophenylylamino)terephthalates
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The reaction of succinyl succinates with aniline, iodoaniline and iodobiphenylamine yielded 2,5-bis(arylamino)-terephthalates. Suzuki cross-coupling reactions of the iodofunctionalized compounds with phenyl- and biphenylylboronic acids gave 2,5-diaminoter
- Zhang, Yawei,Starynowicz, Przemyslaw,Christoffers, Jens
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experimental part
p. 3488 - 3495
(2009/04/14)
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- Substituted 1,3,2,4-benzodithiadiazines: Novel derivatives, by-products, and intermediates
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The synthesis of the title compounds 1 by 1:1 condensation of Ar-N=S=N=SiMe32 with SCl2 followed by intramolecular ortho-cyclization of each [Ar-N=S=N-S-Cl] intermediate is complicated by further reaction of 1 with SCl2 to give Herz salts 3. With the 2:SCl2 ratio of 2:1, the formation of by-products 3 is reduced and novel compounds 1 are accessible. With ortho-I containing starting material 2j, the parent compound 1s is obtained as the result of an unexpected I, not H, substitution. The rate of the 1 + SCl2 reaction depends upon a substituent's position, and the minor 8-R isomers 1l,p (R=Br, I) are isolated for the first time from mixtures with the major 6-R isomers due to reduced reactivity toward SCl2. The synthesized compounds 1-3 are characterized by multinuclear (including nitrogen) NMR and X-ray crystallography. According to the X-ray diffraction data, 1j (6-Br) and 1k (7-Br) derivatives are planar, whereas 1i (5-Br) and 11 (8-Br) are bent along the S1···N4 line by ~5° and ~4°, respectively, and the 1r (7-OCH3) derivative is planar in contrast to the known 5-OCH3 isomer, which possesses a significantly folded heterocycle. The distortion of the planar geometry of some compounds 1 is interpreted in terms of a pseudo-Jahn-Teller effect as the result of π-highest occupied molecular orbital (HOMO) - σ*-(LUMO) lowest unoccupied molecular orbital + 1 mixing in a planar conformation. The 2p compound is the first structurally defined Ar-N=S=N-SiMe3 azathiene. The compound Ar-N=S=N-S-NH-Ar 6 modeling the aforementioned intermediate has been isolated and structurally characterized. We describe the attempts to synthesize compounds 1 from 2-aminobenzenethiols and (SN)4 and from salts 3 and Me3SiN3, and we discuss the reaction pathways.
- Makarov, Alexander Yu,Bagryanskaya, Irina Yu,Gatilov, Yuri V.,Mikhalina, Tatiana V.,Shakirov, Makhmut M.,Shchegoleva, Lyudmila N.,Zibarev, Andrey V.
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p. 563 - 576
(2007/10/03)
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- Substituent effects on the in vitro and in vivo genotoxicity of 4-aminobiphenyl and 4-aminostilbene derivatives
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4-Amino-4'-substituted biphenyls and 4-aminostilbenes substituted in the 3' or 4' position were studied for their in vitro and in vivo genotoxicity. The in vitro mutagenicity of the biphenyls with and without S9 activation was established with Salmonella strains TA98 and TA100 and that of the stilbenes with the same strains plus TA98/1,8-DNP6. The in vivo genotoxicity assay with both series of compounds was for chromosomal aberrations in the bone-marrow cells of mice following intraperitoneal administration of the chemicals. Hammett values of substituents, partition coefficients and frontier orbital energies (E(LUMO) and E(HOMO) of the compounds were used for correlations with mutagenicity. The Salmonella mutagenicity in TA98 and TA98/1,8-DNP6 with S9 was correlated to Hammett σ+ values for the 4-aminostilbene substituents, showing a strong trend of increasing mutagenicity with an increase in the electron-withdrawing capability of the substituent. Hydrophobicity of the stilbenes, however, had little effect on their relative mutagenicity. The 4-aminobiphenyls showed a correlation between their mutagenicity and Hammett σ+ values of their 4'-substituents in stain TA98 with S9, although the trend was not as strong as for the stilbenes. But unlike the stilbenes, TA98 mutagenicity of the biphenyls could also be correlated to hydrophobicity, and structure-activity correlations for the biphenyls was substantially improved when both σ+ and hydrophobicity data were included. For strain TA100 with S9, little correlation was found between mutagenicity of the stilbenes and any of the parameters. However, a limited orrelation did exist between the mutagenicity of the biphenyls and their hydrophobicity. There was also limited correlations of the mutagenicity for the stilbenes in TA98 and TA98/1,8-DNP6 with S9 to E(LUMO) or E(HOMO). The in vivo genotoxicity results for the biphenyls and stilbenes could not be correlated to electronic effects as for the in vivo results, nor could they be explained by hydrophobicity. However, it is interesting to note that 3'-substituted 4-aminostilbenes were all substantially more genotoxic in vivo than their corresponding 4'-substituted counterparts. The most genotoxic compound in vivo in either series was 4-aminostilbene which would not have been predicted from the in vitro results.
- You,Brezzell,Das,Hooberman,Sinsheimer
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