896-06-0Relevant articles and documents
Observation of the complex spectra for the supramolecular system involving silver nanoparticles-biaryl Schiff bases containing the nitro group
Cao, Chao-Tun,Cheng, Shi-Mao,Cao, Chenzhong
, (2020/02/11)
A series of biaryl Schiff bases containing the nitro groups, 4-XArCH═NArNO2-4′ (XBANO2-4′) and 4-NO2ArCH═NArY-4′ (4-NO2BAY), were synthesized. Also, the fish sperm DNA (fsDNA) and silver nanoparticles (AgNPs) solutions were prepared. By mixing these compounds with fsDNA or AgNPs solution and determining the ultraviolet absorption spectra of the mixture solutions, an interesting phenomenon was found: a new absorption peak λmax,lim appeared in the (XBANO2-4′)-AgNPs solution, which was longer than the wavelength of λmax of XBANO2-4′ solution. The new absorption peak in the (XBANO2-4′)-AgNPs solution was the complex spectrum originating from the electron transfer between XBANO2-4′ and AgNPs. Whereas this phenomenon was not observed in the (4-NO2BAY)-AgNPs solutions, a quantitative correlation analysis was carried out with the measured spectral data, and the results show that the wave number νmax,lim of the λmax,lim is mainly affected by the excited-state substituent constant (Formula presented.) rather than the ground Hammett constant σ of the X group. The redshift magnitude Δνmax,WSL, namely, Δνmax,WSL = (1/λmax) ? (1/λmax,lim), of the wavelength λmax,lim is related to the highest occupied molecular orbital and lowest unoccupied molecular orbital of XBANO2-4′. The discovery of this new phenomenon is helpful to understanding the interaction between AgNPs-organic compound supramolecular systems.
Substituent cross-interaction effects on the electronic character of the C=N bridging group in substituted benzylidene anilines - Models for molecular cores of mesogenic compounds. A 13C NMR study and comparison with theoretical results
Neuvonen, Helmi,Neuvonen, Kari,Fueloep, Ferenc
, p. 3141 - 3148 (2007/10/03)
13C NMR chemical shifts δc(C=N) were measured in CDCl 3 for a wide set of mesogenic molecule model compounds, viz. the substituted benzylidene anilines P-X-C6H4CH=NC 6H4-p-Y (X = NO2, CN, CF3, F, Cl, H, Me, MeO, or NMe2; Y = NO2, CN, F, Cl, H, Me, MeO, or NMe2). The substituent dependence of δc(C=N) was used as a tool to study electronic substituent effects on the azomethine unit. The benzylidene substituents X have a reverse effect on δc(C=N): electron-withdrawing substituents cause shielding, while electron-donating ones behave oppositely, the inductive effects clearly predominating over the resonance effects. In contrast, the aniline substituents Y exert normal effects: electron-withdrawing substituents cause deshielding, while electron-donating ones cause shielding of the C=N carbon, the strengths of the inductive and resonance effects being closely similar. Additionally, the presence of a specific cross-interaction between X and Y could be verified. The electronic effects of the neighboring aromatic ring substituents systematically modify the sensitivity of the C=N group to the electronic effects of the benzylidene or aniline ring substituents. Electron-withdrawing substituents on the aniline ring decrease the sensitivity of δc(C=N) to the substitution on the benzylidine ring, while electron-donating substituents have the opposite effect. In contrast, electron-withdrawing substituents on the benzylidene ring increase the sensitivity of δc(C=N) to the substituent on the aniline ring, while electron-donating substituents act in the opposite way. These results can be rationalized in terms of the substituent-sensitive balance of the electron delocalization (mesomeric effects). The present NMR characteristics are discussed as regards the computational literature data. Valuable information has been obtained on the effects of the substituents on the molecular core of the mesogenic model compounds.
ELECTRONIC ABSORPTION SPECTRA OF AROMATIC SCHIFF BASES. PART III. p-PHENYLENEDIAMINE DERIVATIVES
Gawinecki, Ryszard,Muzalewski, Feliks
, p. 1091 - 1098 (2007/10/02)
The effect of para substituents in the benzylidene-p-dimethylaminoaniline and dibenzylidene-p-phenylenediamine molecules on their UV-VIS spectra has been studied.A linear relationship has been found between position of the most long-wavelength absorption
Syntheses of 5-benzylamino>-9-N,N-dialkylaminobenzophenoxazonium Chlorides
Sen, A. K.,Mukhopadhyay, Sankardeb
, p. 642 - 645 (2007/10/02)
Reaction of 4-benzylidene-4'-N,N-dimethylaminoaniline (I) with 4-nitrobenzaldehyde in ethanol induces an aldehyde exchange reaction to provide 4-benzaldehyde (II) in crystalline form. 4-benzylidene-α-naphthylamine (IV) obtained by reaction of II with α-naphthylamine, on reduction with sodium amalgam gives 4-benzyl-α-naphthylamine (V).Condensation of V with 5-dimethylamino-2-nitrosophenol and 5-diethylamino-2-nitrosophenol in HCl affords 5-benzylamino>-9-N,N-dimethylaminobenzo phenoxazonium chloride hydrochloride (VI) and 9-N,N-diethylamino analogue (VII), respectively.Treatment of VI and VII with thionyl chloride furnishes 5-benzylamino>-9-N,N-dimethylaminobenzophenoxazonium chloride hydrochloride (VIII) and 9-diethylamino analogue (IX), respectively.The aldehyde exchange method is found to be a useful variant in the preparation of 4-N,N-dimethylaminobenzaldehyde.
SEMICONDUCTIVITY OF ORGANIC SUBSTANCES-15
ELEY DD,NEWMAN OMG
, p. 1106 - 1112 (2007/10/05)
Part 15 treats compounds related to stilbene. Dark conductivity in diphenylbutadiene and four analogs of stilbene has been examined. The compounds were chosen to reveal the possible effects of a donor and an acceptor group attached to opposite ends of the
