2844-17-9Relevant academic research and scientific papers
Catalytic Amide-Base System of TMAF and N(TMS)3 for Deprotonative Coupling of Benzylic C(sp3)-H Bonds with Carbonyls
Shigeno, Masanori,Nakaji, Kunihito,Nozawa-Kumada, Kanako,Kondo, Yoshinori
supporting information, p. 2588 - 2592 (2019/04/25)
This paper describes that an amide-base generated in situ from tetramethylammonium fluoride (TMAF) and N(TMS)3 catalyzes the deprotonative coupling of benzylic C(sp3)-H bonds with carbonyls to form stilbenes. A variety of methylheteroarenes (2-methylbenzothiophene, 2-methylbenzofuran, and 2-, 3-, or 4-methylpyridines) are used as nucleophiles. Application to enamine synthesis using DMF as an electrophile is also shown. The present system is effective for toluenes (4-phenyl-, 4-bromo-, 2-bromo-, and 4-chlorotoluenes) having low reactivity.
Comparison between organic sensitizers containing stilbene and azo group as bridging unit for dye sensitized solar cells
Park, Se Woong,Namgoong, Jin Woong,Kwon, Il Keun,Kim, Jae Pil
, p. 7502 - 7507 (2014/12/10)
While azo dyes have been widely used in dye industry, the azo dyes have been seldom applied as sensitizers to dye sensitized solar cells. In this study, new metal-free organic sensitizers, ST and AZ, which are same structures except bridging units, were synthesized and evaluated. ST containing stilbene as bridging unit gave higher energy conversion efficiency than AZ containing azo group as bridging unit. As a result of density functional theory (DFT) calculations, ST displayed more localized frontier molecular orbitals at lowest unoccupied molecular orbital (LUMO) states than AZ.
Unconventional Langmuir-Blodgett films: Alignment of an optically nonlinear dye where the donor and π-electron bridge are hydrophobic and the acceptor is hydrophilic
Ashwell, Geoffrey J.,Maxwell, Alison A.,Green, Andrew
, p. 2192 - 2196 (2007/10/03)
The optically nonlinear dye, 5-{4-[2-(4-dibutylaminophenyl)vinyl]benzylidene}-2-(1-ethylpropyl)-5,6,7, 8-tetrahydroisoquinolinium bromide (1a), differs from other Langmuir-Blodgett (LB) film-forming materials. The molecule is amphiphilic and, therefore, may be aligned at the air-water interface but, instead of a conventional aliphatic tail, has an extended π-electron bridge. It forms non-centrosymmetric LB films which exhibit second-harmonic generation (SHG) and have a high second-order susceptibility: χ(2)zzz = 40 pm V-1 at 1.064 μm for a monolayer thickness of 1.8 nm and chromophore tilt angle of 55° from the substrate normal. The octadecyl sulfate salt (1b) also forms non-centrosymmetric films but with improved properties: χ(2)zzz = 90 pm V-1 at 1.064 μm for d = 2.4 nm and φ = 33°. Both films exhibit charge-transfer bands at 360 nm but with absorbance cut-off above 560 nm for 1a and 530 nm for 1b. The latter is fully transparent at the fundamental and harmonic wavelengths and its susceptibility is the highest to date for such a film. This results from an optimised packing arrangement, a conjugation enhanced molecular hyperpolarisability of β = 4.3 × 10-38 m4 V-1, and the proximity of the absorption band, albeit non-overlapping at 532 nm. The properties are compared with those of conventional long alkyl tailed materials (2 and 3) of the same chromophore.
An improved efficiency/transparency trade-off for second-harmonic generation by extending the π-electron bridge of an optically nonlinear dye
Ashwell, Geoffrey J.,Whittam, Anne J.,Amiri, Mukhtar A.,Hamilton, Richard,Green, Andrew,Grummt, Ulrich-Walter
, p. 1345 - 1350 (2007/10/03)
The second-harmonic intensity from Langmuir-Blodgett films of 5-{4-[2-(4-dimethylaminophenyl)vinyl]benzylidene}-2-octadecyl-5,6,7,8- tetrahydroisoquinolinium octadecyl sulfate(1), interleaved with poly(tert-butyl methacrylate), increases quadratically with thickness to more than 100 bilayers. The susceptibility, molecular hyperpolarisability, thickness, refractive indices and chromophore tilt angle, relative to the substrate normal, are Xzzz(2)=45 ± 5 pm V-1 at 1064 nm, β = 8 × 10-38 m4 V-1, l=3.65 ± 0.12 nm bilayer -1, nω = 1.56 ± 0.01 and ψ = 44 ± 2 °. The moderately high susceptibility arises from an optimised transparency/efficiency trade-off, the alternate-layer LB film being transparent at 1064 nm and having a very slight absorbance of 3.5 × 10-4 bilayer -1 at 532 nm. In contrast, alternate-layer films of the correseponding 7-diethylamino-2-oxo-2H-chromen-3-ylmethylene (2) and 3-(dimethylaminophenyl)prop-2-enylidene (3) derivatives, also reported, have absorbances of 1.1 × 10-3 and 1.5 × 10-3 bilayer-1 at 532 nm and resonantly enhanced susceptibilities of 60 and 95 pm V-1 respectively.
Inhibition of purified and membrane-bound flavin-containing monooxygenase 1 by (N,N-dimethylamino)stilbene carboxylates
Clement, Bernd,Weide, Matthias,Ziegler, Daniel M.
, p. 599 - 604 (2007/10/03)
(E)-[2-(4-(Dimethylamino)phenyl)vinyl]benzenes bearing a nitrile or carboxyl group in the 2', 3', or 4' position were synthesized and tested for substrate activity with purified pig liver flavin-containing monooxygenase (FMO1). Although the nitrile derivatives were too insoluble to saturate the catalytic site at pH 7.4, they appeared to be substrates with K(m)'s somewhat above their maximum solubility (?0.1 mM) in the assay medium. Of the three carboxylic acid analogs, (E)-4-[2-(4-(dimethylamino)phenyl)vinyl]benzoic acid had no detectable water solubility at pH 7.4, and measurements were restricted to (E)-3-[2-(4-(dimethylamino)phenyl)vinyl]benzoic acid (DS3CO) and (E)-2-[2-(4-(dimethylamino)phenyl)vinyl]benzoic acid (DS2CO). While DS3CO and DS2CO were substrates, they also inhibited FMO1 turnover. DS3CO was the more effective inhibitor, and at 2 mM it inhibited FMO1 and microsomal- catalyzed oxidation of methimazole (N-methyl-2-mercaptoimidazole) by 80-90%. Kinetic studies indicated that the aminostilbene carboxylates were noncompetitive with both the xenobiotic substrate, methimazole, and NADPH. However, inhibition constants calculated from double reciprocal plots of velocity vs NADPH were K(i)(comp) 130 and 150 μM for DS3CO and DS2CO, respectively, whereas the uncompetitive K(i)'s were 10-15 times higher, which suggests that inhibition of NADPH binding may be primarily responsible for inhibition of FMO1 by the aminostilbene carboxylates. This model is also consistent with inhibition of cyclohexanone monooxygenase, a bacterial analog of FMO. DS3CO and DS2CO were again noncompetitive with methimazole but primarily competitive with NADPH. The aminostilbene carboxylates had no detectable effects on activity of pig or rat liver NADPH-cytochrome P450 reductase, which suggests that they are not nonspecific flavoprotein antagonists.
Electronic Structure and Free-Energy Relationships for Some 4'-Substituted 4-Dimethylamino trans-Stilbenes by U.V. Photoelectron Spectroscopy
Cauletti, C.,Furlani, C.,Palma, A.,Piancastelli, M. N.,Schleinitz, K. D.,Gloyna, D.
, p. 829 - 836 (2007/10/02)
A series of 4'-substituted 4-dimethylamino trans-stilbenes 1-5 was investigated by UPS, in connection with conjugated donor-acceptor substituted double bond photochemistry.The measured and assigned spectra indicate a high sensitivity, depending on the changed electronic structure by 4'-substituents of compounds 1-5.Correlation of ionization energies in LFE-relationship with Hammett's ?p-values and other ground state data was proved, demonstrating UPS a powerful tool for substituent effect studies in conjugated double bond systems.
Aromatic Phosphines with Second Order Substituents, XVI. - Phenylogous PO-activated Olefination: Synthesis of 4'-Donator Substituted 4-(Diphenylphosphinyl)stilbenes
Schiemenz, Guenter Paulus,Finzenhagen, Manfred
, p. 1476 - 1484 (2007/10/02)
Being a -M substituent, the 4-diphenylphosphinyl group acidifies the methyl group of toluene to a similar degree as a 4-cyano group.The carbanion formed by deprotonation reacts with N-benzylidene anilines to yield 4-(diphenylphosphinyl)stilbenes.In these, UV-spectroscopically the phosphorus on the one hand behaves like a -M substituent, on the other hand it acts as a barrier to through-conjugation.
