52197-23-6Relevant academic research and scientific papers
Novel phenyl-substituted pyrazinoporphyrazine complexes of rare-earth elements: optimized synthetic protocols and physicochemical properties
Kosov,Dubinina,Borisova,Ivanov,Drozdov,Trashin,De Wael,Kotova,Tomilova
, p. 3153 - 3161 (2019)
Novel synthetic protocols based on both template and multi-step methods were developed for phenyl-substituted pyrazinoporphyrazine complexes of rare-earth elements (Y, Eu, Gd, Dy, Er and Lu). p-Hydroquinone was employed as a reaction medium and as a reducing agent in the process of porphyrazine macrocycle formation. Both thermal and microwave irradiation techniques were successfully applied for activation of the template macrocyclization process. An alternative multi-step approach involving the initial stage of free-base ligand formation was realized for the lutetium compound. The target complexes were identified by high-resolution mass spectrometry, infrared spectroscopy and nuclear magnetic resonance (NMR) spectroscopy. Electrochemical behavior in solution and UV-vis absorbance in solutions and films were studied as well. Shifts in the position of the Q band and oxidation-reduction potentials in comparison with corresponding phthalocyanine analogues were noticed. Using the IR absorption spectra recorded in the temperature range of 170-300 K, the position of the Fermi level of ?4.7 ± 0.1 eV and a characteristic energy diagram were obtained for the erbium complex.
Titanium-Based Tetrakis-2,3-[5,6-di(Substituted)pyrazino]porphyrazine: Synthesis and Characterization
Assunta Navarra, Maria,D'Acunzo, Francesca,Gentili, Patrizia,Geppi, Marco,Mancone, Carmine,Martini, Francesca,Mazzapioda, Lucia,Nardelli, Francesca,Renzi, Polyssena
supporting information, (2020/06/17)
Tetrapyrazinoporphyrazine (TPysPz) ligands and metal complexes find, generally, application as electronic materials and catalysts. Considering the limited application of Titanium (Ti), we prepared and characterized a family of ligands and Ti-based complexes of tetrakis-2,3-[5,6-di-R8-pyrazino]porphyrazine (R = H, 2-Py, Ph). UV/Vis measurements in different solvents confirm molecular aggregation, which results more pronounced in the presence of 2-pyridil and phenyl substituents on the macrocycle edge. Because of low solubility, solid state NMR was applied for structure characterization. Additional IR and MALDI-TOF were carried out to complete the characterization. Cyclic voltammetry in DMSO/Bu4NBF4 0.1 m unveiled that our Ti complexes can take part in up to five redox events. The first two quasi-reversible reductions involve Ti(IV), whereas the further to or three occur at the expense of the TPysPz macrocycle. To test the applicability of our compounds as catalytic materials, we performed a preliminary cyclic voltammetry investigation in the solid-state, which showed typical peaks of hydrogen redox reactions.
Subphthalocyanine azaanalogues – Boron(III) subporphyrazines with fused pyrazine fragments
Stuzhin, Pavel A.,Skvortsov, Ivan A.,Zhabanov, Yuriy A.,Somov, Nikolai V.,Razgonyaev, Oleg V.,Nikitin, Ivan A.,Koifman, Oskar I.
, p. 888 - 897 (2018/11/25)
Сyclotrimerization of pyrazine-2,3-dicarbonitrile and its phenyl substituted derivative in the presence of BCl3 in p-xylene leads to azaanalogues of subphthalocyanine dye. Non-substituted tripyrazinosubporphyrazine [Pyz3sPABCl] was formed only in trace amounts allowing only limited spectral study in solution. Hexaphenyl substituted derivative [Ph6Pyz3sPABCl] was isolated as chlorboron(III) complex and fully characterized by 1H, 13C, 11B NMR, IR, electronic absorption and emission spectroscopy, cyclovoltammetry and its structure was established by single crystal X-ray diffraction. Pyrazine fused subporphyrazines exhibit strong absorption bands at 300–310 and 530–550 nm. The phenyl substituted derivative [Ph6Pyz3sPABCl] has an additional intense charge transfer band at 390 nm and can be reversibly reduced at ?0.81 V (vs Ag/AgCl in MeCN). The influence of pyrazine rings on the geometrical and electronic structural features and spectral properties of subporphyrazine dye was also studied using DFT and TD DFT methods. Experimental and theoretical results evidence that fusion of pyrazine rings leads to stabilization of the frontier π-molecular orbitals and endows the macrocycle with enhanced electron deficiency. Pyrazine fused subporphyrazines can be considered as perspective dyes intensively absorbing in the 300–600 nm range for applications as n-type materials in organic electronics.
Silica gel an efficient catalyst for one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones and their analogs
Chakraborty, Rakesh Ranjan,Singha, Rabindranath,Ghosh, Pranab
, p. 373 - 378 (2018/09/29)
A straightforward one-pot synthesis of pyrazines from ethylenediamine and 1, 2-diketones/ α-hydroxy ketone/α-bromo ketone under solvent-free conditions at room temperature is described. This environmentally benign process has the edge on previous methods in respect of workup procedure, ease and cost of reaction, and use and generation of hazardous substances. The catalyst is recovered, characterized, and proved to be recyclable for successive four runs examined with appreciable conversions.
Clean and green approach for one-pot synthesis of pyrazines from Eth-ylenediamine and 1,2-diketone or its analogues under neat reaction condition
Ghosh, Pranab,Chakraborty, Rakesh Ranjan
, p. 566 - 570 (2017/09/29)
Background: Compounds having N-heterocyclic moieties are of huge importance in the field of agrochemical, pharmaceutical, biological, fragrances, etc. Due to a lot of applications associated with pyrazine moieties, their synthesis has always been important for organic chemists. Method: Surfeit synthetic methodologies are documented in literature. Most of the methodologies used expensive solvents, harmful metal catalyst and all suffer from rigorous work-up procedures. An efficient, environmentally benign methodology, needs to be developed. We mixed ethylenediamine (2mmol) with 1, 2-diketone(1mmol), later, α-hydroxy ketone and α-bromo ketone on magnetic stirrer at room temperature under neat reaction condition for 5 to 10 hrs. Results: After purification by column chromatography using silica gel(60-120 mesh) and pet-ether, et-hylacetate mixture as eluent, we achieved pyrazine derivatives from moderate to high yield. Conclusio n: Efficient and clean procedure for one-pot preparation of pyrazines from ethylenediamine and 1, 2-diketones or with α-hydroxy ketone or with α-bromo ketone has been carried out under neat reaction condition at room temperature. Environmentally benign process furnishing moderate to excellent yields of the product and simple work-up giving pure products are special features of this reaction.
Dicyanopyrazine-derived push-pull chromophores for highly efficient photoredox catalysis
Zhao, Yu,Zhang, Chenhao,Chin, Kek Foo,Pytela, Oldrich,Wei, Guo,Liu, Hongjun,Bures, Filip,Jiang, Zhiyong
, p. 30062 - 30067 (2014/08/05)
Here, we report dicyanopyrazine (DPZ)-derived push-pull chromophores, easily prepared and tunable organic compounds, as new kinds of photoredox catalysts. In particular, the DPZ derivative H, containing 2-methoxythienyl as electron-donating moiety, exhibits a broad absorption of visible light with an absorption edge up to 500 nm and excellent redox properties, and has been demonstrated as a desirably active and efficient photoredox catalyst in four challenging kinds of photoredox reactions. The amount of catalyst in most reactions is less than 0.1 mol% and even 0.01 mol%, representing the lowest catalyst loading in the current photoredox organocatalysis. the Partner Organisations 2014.
γ-Maghemite-silica nanocomposite: A green catalyst for diverse aromatic N-heterocycles
Ghosh, Pranab,Mandal, Amitava,Subba, Raju
, p. 146 - 152 (2013/09/02)
γ-Maghemite-silica nanocomposite has been applied as a green catalyst to synthesize variety of aromatic N-heterocycles under solvent free conditions. Characterization was done by modern analytical tools (UV, IR, AAS, DSC, EDXRF, powdered XRD, EPR, Mo?ssbauer and TEM). Mild reaction conditions and recyclability have made the present protocol both environmentally and economically viable.
An easy route for the synthesis of pyrazine-2,3-dicarbonitrile 5,6-bis-substituted derivatives using a palladium catalyst
Ali, Hasrat,Van Lier, Johan E.
scheme or table, p. 4824 - 4827 (2012/09/25)
An easy synthetic method for the preparation of pyrazine-2,3-dicarbonitrile 5,6-bis-substituted derivatives using Pd-catalyzed cross coupling reaction (Sonogashira, Suzuki, Heck) is described. The reaction conditions allow preparing symmetrical and unsymmetrical bis-substituted products in moderate to high yields, as precursors for the preparation of highly substituted symmetrical and non-symmetrical aza-phthalocyanines with well-defined spectral properties.
One-pot synthesis and characterization of new cuprous pyrazinoporphyrazines containing peripherally functionalized units
Khodaee, Ziba,Yahyazadeh, Asieh,Mahmoodi, Nosrat O.,Zanjanchi, Mohammad Ali,Azimi, Vahid
, p. 92 - 97 (2013/01/15)
The synthesis and characterization of some new peripherally substituted Cu-pyrazinoporphyrazines (Cu-Pzs) is described. The prepared α-dicyano compounds in the presence of cuprous chloride produced porphyrazine counterparts via one-pot cyclotetramerization reaction. The resulted porphyrazines are useful photosensitizers and good reagent for photodynamic therapy of cancer.
Red-emitting dyes with photophysical and photochemical properties controlled by pH
Novakova, Veronika,Miletin, Miroslav,Kopecky, Kamil,Zimcik, Petr
scheme or table, p. 14273 - 14282 (2012/01/06)
New unsymmetrical zinc azaphthalocyanines, bearing one substituted aniline as a peripheral substituent, were prepared by using a statistical condensation approach. Both fluorescence and singlet oxygen quantum yields were extremely low in DMF (φFΔF=0. 22-0.29, φΔ=0.40-0.59, respectively). This behavior was attributed to the deactivation of excited states by intramolecular charge transfer from a donor site (aniline), which was blocked after protonation in acidic media. In the protonated form, all of the compounds efficiently emitted light with λem in the region of 662-675 nm. The investigated compounds were anchored to dioleoylphosphatidylcholine (DOPC) unilamellar vesicles and showed response to buffer pH. They were highly fluorescent at low pH values and almost nonfluorescent in neutral solutions. The pKa values were determined in DOPC vesicles and ranged between 2.2 and 4.2.
