18156-75-7Relevant articles and documents
Versatile Tri(pyrazolyl)phosphanes as Phosphorus Precursors for the Synthesis of Highly Emitting InP/ZnS Quantum Dots
Panzer, René,Guhrenz, Chris,Haubold, Danny,Hübner, René,Gaponik, Nikolai,Eychmüller, Alexander,Weigand, Jan J.
, p. 14737 - 14742 (2017/10/23)
Tri(pyrazolyl)phosphanes (5R1,R2) are utilized as an alternative, cheap and low-toxic phosphorus source for the convenient synthesis of InP/ZnS quantum dots (QDs). From these precursors, remarkably long-term stable stock solutions (>6 months) of P(OLA)3 (OLAH=oleylamine) are generated from which the respective pyrazoles are conveniently recovered. P(OLA)3 acts simultaneously as phosphorus source and reducing agent in the synthesis of highly emitting InP/ZnS core/shell QDs. These QDs are characterized by a spectral range between 530–620 nm and photoluminescence quantum yields (PL QYs) between 51–62 %. A proof-of-concept white light-emitting diode (LED) applying the InP/ZnS QDs as a color-conversion layer was built to demonstrate their applicability and processibility.
Indazaboles - Synthesis and molecular structure
Wrackmeyera, Bernd,Shahid, Khadija,Kempe, Rhett,Doering, Christian,Milius, Wolfgang
experimental part, p. 398 - 401 (2010/07/16)
The reaction of 1-trimethylsilyl-indazole with boranes affords indazaboles accompanied by elimination of trimethysilane. Thus, the two isomers of parent indazabole are formed in a 1 : 1 ratio using borane in THF (BH3/THF), characterized by NMR spectroscopy in solution (1H, 11B and 13C NMR). In contrast, the analogous reaction with 1, 2-bis(tetramethylene)diborane(6) proceeds to give a single isomerof the B-alkylated indazabole via symmetric ring cleavage of the diborane(6), as shown by NMR in solution and X-ray structural analysis in the solid state. The molecular structure is fluxional in solution. In the solid state, the central B2N4 ring adopts a distorted boat conformation. Calculated gas phase geometries of the parent indazaboles and of the B-alkylated indazabole were optimized by DFT methods at the B3LYP/6-311+G(d,p) level of theory. Copyright
MECANISME DE DECARBONYLATION DE PYRAZOLIDES IONISES PAR IMPACT ELECTRONIQUE
Flammang, Robert,Abdelouahab, Fouad Bachir Ben,Munkengeshayi, Kadiebwe,Boulanger, Pierre
, p. 215 - 226 (2007/10/02)
Electron impact ionization of 1-acryloylpyrazole induces a unimolecular loss of CO forming ionized 1-vinylpyrazole as shown by metastable ion characteristics and neutralization-reionization data.This CO loss implies a rate-determining isomerization process into a pyrazolylmethyl ketene structure 1a+..These ketene ions have been synthetized in the ion source by dissociative ionization of pyrazolylpropionylpyrazoles.Flash-vacuum pyrolysis of these compounds also affords the expected neutral ketenes in the gas phase, which are however readily converted into the acryloyl isomers by an intramolecular nucleophilic process.
Alkylation, Acylation and Silylation of Azoles
Begtrup, Mikael,Larsen, Peter
, p. 1050 - 1057 (2007/10/02)
Performing alkylation, acylation and silylation reactions in separate deprotonation and nucleophilic displacement steps allows for better control of reaction conditions and facilitates problem handling in these processes.In the alkylation of azoles the alkylating agents and solvents possess individual reaction capabilities which seem to be approximately additive.Monoalkylation occurs if the sum of the normalized reaction potentials is equal or larger than the pKa value of the azole.Dialkylation is avoided by keeping the sum of the normalized reaction potentials below the pKa value of the alkylazole.The applicability of these principles is demonstrated by the development of effective procedures for the methylation, benzylation, acetylation, methoxycarbonylation and trimethylsilylation of azoles.
Synthesis of 1-Oxo-1H-pyrazolotriazol-4-ium-3-olates. - A Ring-Chain Tautomerism in the Series of Bicyclic Dipolar Heterocycles
Boettcher, Andreas,Debaerdemaeker, Tony,Radziszewski, Juliusz G.,Friedrichsen, Willy
, p. 895 - 908 (2007/10/02)
1-(Trimethylsilyl)pyrazole (12) reacts with chlorocarbonyl isocyanate to give a compound, which - dependent on the state of aggregation - may exist both as a bicyclic dipolar heterocycle (7) and as monocyclic 1-pyrazolyl carbonyl isocyanate (8).Methyl-substituted derivatives (19a, b) show a similar behaviour.MNDO calculations for the parent systems (7, 8) are in accord with these experimental observations.The structure of 5,6,7-trimethyl-1-oxo-1H-pyrazolotriazol-4-ium-3-olate (19b) has been clarified by X-ray analysis.
