3025-52-3Relevant academic research and scientific papers
Carboxyl and nitrite functionalized graphene quantum dots as a highly active reagent and catalyst for rapid diazotization reaction and synthesis of azo-dyes under solvent-free conditions
Valizadeh, Hassan,Shomali, Ashkan,Nourshargh, Saideh,Mohammad-Rezaei, Rahim
, p. 522 - 528 (2015/03/18)
Carboxyl and nitrite functionalized graphene quantum dots was prepared from carboxyl and hydroxyl functionalized graphene quantum dots using NaNO2 in the absence of mineral acids. This functional group conversion was confirmed by FT-IR spectroscopy, photoluminescence and X-ray diffraction. The carboxyl and nitrite functionalized graphene quantum dots was used as an effective nitrosonium ion source and reusable catalyst for the efficient diazotization of a variety of arylamines without using any additional acid. Subsequent azo-coupling of these freshly prepared diazonium salts with a range of active aromatic compounds led to the requisite azo-dyes in excellent yields in very short reaction times with a simple experimental procedure.
Tuning photochromic ion channel blockers
Mourot, Alexandre,Kienzler, Michael A.,Banghart, Matthew R.,Fehrentz, Timm,Huber, Florian M. E.,Stein, Marco,Kramer, Richard H.,Trauner, Dirk
, p. 536 - 543 (2015/02/02)
Photochromic channel blockers provide a conceptually simple and convenient way to modulate neuronal activity with light. We have recently described a family of azobenzenes that function as tonic blockers of Kv channels but require UV-A light to unblock and need to be actively switched by toggling between two different wavelengths. We now introduce red-shifted compounds that fully operate in the visible region of the spectrum and quickly turn themselves off in the dark. Furthermore, we have developed a version that does not block effectively in the dark-adapted state, can be switched to a blocking state with blue light, and reverts to the inactive state automatically. Photochromic blockers of this type could be useful for the photopharmacological control of neuronal activity under mild conditions.
Nanoparticles of organosilane-based nitrite ionic liquid immobilized on silica for the diazotization of aniline derivatives and subsequent synthesis of azo dyes
Valizadeh, Hassan,Amiri, Mohammad,Hosseinzadeh, Fatemeh
, p. 1308 - 1313 (2012/03/27)
Imidazolium based nitrite ionic liquid containing trimethoxysilyl group was prepared from the reaction of N-methylimidazole and (3-chloropropyl) trimethoxysilane. This ionic liquid was immobilized on silica covalently to give nanoparticles with the imidazolium nitrite moiety remaining intact. The diazotization reaction was performed as a model reaction to examine the activity of these nanoparticles as a nitrosonium source. Excellent performance was exhibited in the diazotization reaction of various aniline derivatives in the presence of HCl under mild heterogeneous conditions (room temperature and short reaction time). In-situ coupling of diazonium salts to a range of tertiary anilines, phenols and naphthols afforded the requisite azo dyes in good yield, using standard experimental procedures.
A new nitrite ionic liquid (IL-ONO) as a nitrosonium source for the efficient diazotization of aniline derivatives and in-situ synthesis of azo dyes
Valizadeh, Hassan,Shomali, Ashkan
experimental part, p. 1138 - 1143 (2012/03/27)
A new task-specific nitrite containing ionic liquid derived from the O-nitrosation of N-methyl-N-hydroxybutylimidazolinium chloride was synthesized and used as a source of nitrosonium ion to affect the efficient diazotization of arylamines. The diazonium salts thus obtained were coupled, using standard experimental procedures, to a range of tertiary anilines, phenols and naphthols to afford the requisite azo dyes in good yield. The diazotization and subsequent azo-coupling generated the related azo dyes at 0-5 °C in short reaction times with a simple experimental procedure.
Ionic liquid 1-(3-trimethoxysilylpropyl)-3-methylimidazolium nitrite as a new reagent for the efficient diazotization of aniline derivatives and in situ synthesis of azo dyes
Valizadeh,Amiri,Shomali,Hosseinzadeh
experimental part, p. 495 - 501 (2012/07/13)
A new ionic liquid 1-(3-trimethoxysilylpropyl)-3-methylimidazolium nitrite was synthesized. This ionic liquid was used as a convenient nitrosonium source in diazotization of arylamines into their corresponding diazonium salts which were converted into their related azo dyes via the in situ azo-coupling with aniline derivatives or phenolic compounds. The diazotization of anilines in this ionic liquid and subsequent azo-coupling generated the related azo dyes in good to excellent yields at 0-5 °C in short reaction times via a simple experimental procedure.
Nitration of Anilinium Ions in Concentrated Sulfuric Acid, Catalyzed by Nitrosonium Hydrogen Sulfate
Gorelik, M. V.,Lomzakova, V. I.,Khamidova, E. A.,Shteiman, V. Ya.,Kuznetsova, M. G.
, p. 371 - 374 (2007/10/03)
Successive treatment of aniline first with nitrosonium hydrogen sulfate and then with nitric acid in concentrated sulfuric acid results in nitration of the anilinium ion in the para position, catalyzed by the nitrosonium salt, along with noncatalytic nitration in the meta and para position.No diazotization of aniline followed by nitration of the benzenediazonium cation occurs.
Supercritical Carbon Dioxide. The Cis to Trans Relaxation and ?,?* Transition of 4-(Diethylamino)-4'-nitroazobenzene
Sigman, Michael E.,Leffler, John E.
, p. 3123 - 3126 (2007/10/02)
Rates of the cis-trans isomerization of 4-(diethylamino)-4'-nitroazobenzene (DENAB) have been determined for supercritical CO2 media at 32.4 deg C and several densities and DENAB concentrations.A plot of ΔG (excit.) against the Kamlet-Taft ?* parameter has two linear parts, one for the CO2 media and alkanes and another for more polar solvents.The slope for the CO2 and alkanes is positive and small, and that for the other solvents is large and negative.It is suggested that the reaction mechanism in the CO2 media and in alkanes is inversion at one of the azo nitrogens, while in the more polar solvents it is rotation about the bond between the azo nitrogens, for which the transition state is much more polar.The point of intersection of the two lines is at a ?* value of about +0.2.Unlike the ΔG (excit.) values, the Emax of the ?,?* internal charge-transfer band of DENAB are adequately accommodated by a single line
Studies on UV/Vis Absorption Spectra of Azo Dyes. XVIII. Substituent Effects on the Absorption Maxima of the n-->?* and ?-->?* Bands of 4-N,N-Diethylaminoazobenzenes
Haessner, Carmen,Mustroph, H.
, p. 493 - 498 (2007/10/02)
The spectra of 27 substituted 4-N,N-diethylaminoazobenzenes are determined.The band system can be separated by deconvolution into two Gaussian curves.The results so obtained show that the effects of substituents on n-->?* and ?-->?* transitions are similar and that electron withdrawing substituents in the phenylazo residue cause a bathochromic shift of both the n-->?* and the ?-->?* bands.
