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Solid Argon (solid + argon)

Distribution by Scientific Domains
Chemistry85%

Selected Abstracts

Photochemistry of Salicylaldoxime in Solid Argon: An Experimental and Theoretical Study

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2010
Joanna Grzegorzek
Abstract The photochemistry of salicylaldoxime in solid argon has been investigated by FTIR spectroscopy and DFT calculations. The salicylaldoxime molecule trapped in the matrix from the vapor above the solid sample has the most stable syn1 conformation with an intramolecular hydrogen bond. Irradiation (, > 320 nm) leads to conversion of the syn1 conformer into the syn3 one, in which the C(H)NOH and (C)OH groups are rotated around the C,C and C,O bonds, respectively, and the intramolecular hydrogen bond is broken. The photochemistry of syn3 involves three possible routes: (i) conversion of syn3 into anti2 conformer, this process requires rearrangement of the NOH group with respect to the C=N bond; (ii) photodissociation of salicylaldoxime into 2-cyanophenol and water, which form a hydrogen-bonded complex; and (iii) regeneration of the syn1 conformer. The third route is a very small contribution to the overall process. The study performed with [D2]salicylaldoxime indicates that the dehydration reaction of salicylaldoxime involves cleavage of the N,O bond and formation of OH and Ph(OH)C(H)N radicals in the first step. Then, the OH radical abstracts a hydrogen atom from the CH group to form 2-cyanophenol and water molecules. When the sample is exposed to the full output of the mercury lamp the 2-cyanophenol complex with water becomes the dominating product. [source]

Infrared Spectra of M(OH)1,2,4 (M: Pb, Sn) in Solid Argon.

CHEMINFORM, Issue 50 2005
Xuefeng Wang
No abstract is available for this article. [source]

Infrared Spectra and DFT Calculations for the Coinage Metal Hydrides MH, (H2)MH, MH2, M2H, M2H - , and (H2)CuHCu in Solid Argon, Neon, and Hydrogen.

CHEMINFORM, Issue 1 2004
Xuefeng Wang
No abstract is available for this article. [source]

Photochemistry of Salicylaldoxime in Solid Argon: An Experimental and Theoretical Study

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 27 2010
Joanna Grzegorzek
Abstract The photochemistry of salicylaldoxime in solid argon has been investigated by FTIR spectroscopy and DFT calculations. The salicylaldoxime molecule trapped in the matrix from the vapor above the solid sample has the most stable syn1 conformation with an intramolecular hydrogen bond. Irradiation (, > 320 nm) leads to conversion of the syn1 conformer into the syn3 one, in which the C(H)NOH and (C)OH groups are rotated around the C,C and C,O bonds, respectively, and the intramolecular hydrogen bond is broken. The photochemistry of syn3 involves three possible routes: (i) conversion of syn3 into anti2 conformer, this process requires rearrangement of the NOH group with respect to the C=N bond; (ii) photodissociation of salicylaldoxime into 2-cyanophenol and water, which form a hydrogen-bonded complex; and (iii) regeneration of the syn1 conformer. The third route is a very small contribution to the overall process. The study performed with [D2]salicylaldoxime indicates that the dehydration reaction of salicylaldoxime involves cleavage of the N,O bond and formation of OH and Ph(OH)C(H)N radicals in the first step. Then, the OH radical abstracts a hydrogen atom from the CH group to form 2-cyanophenol and water molecules. When the sample is exposed to the full output of the mercury lamp the 2-cyanophenol complex with water becomes the dominating product. [source]

Photochemistry of cis -3-Diazo-5,6-dimethyl-1,4-oxathian-2-one S -Oxide in Argon Matrices

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 13 2006
Orlagh C. M. O'Sullivan
Abstract The photochemistry of the ,-diazo sulfoxide 7 has been investigated in solid argon at 10 K by IR spectroscopy. The sulfinyl carbene was not detected directly but instead underwent photochemically induced hetero-Wolff rearrangement to the sulfine 8 which could be detected and characterized following irradiation at 248 nm. Further photochemical reaction of this intermediate led to the oxathiirane 9 which was most readily detected on irradiation of 7 at 308 nm. The matrix-isolated species were identified by comparison of experimental and calculated IR spectra. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Matrix isolation and magnetic parameters of septet 3,5-dicyanopyridyl-2,4,6-trinitrene

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2010
Sergei V. Chapyshev
Abstract Septet 3,5-dicyanopyridyl-2,4,6-trinitrene was synthesized together with quintet 2-azido-3,5-dicyanopyridyl-4,6-dinitrene, quintet 4-azido-3,5-dicyanopyridyl-2,6-dinitrene, triplet 2,6-diazido-3,5-dicyanopyridyl-4-nitrene, and triplet 2,4-diazido-3,5-dicyanopyridyl-6-nitrene by photolysis of 2,4,6-triazido-3,5-dicyanopyridine in solid argon at 4,K. The electronic and magnetic properties of the matrix-isolated nitrenes were studied using electron paramagnetic resonance (EPR) spectroscopy in combination with density functional theory (DFT) calculations. The fine-structure parameters of the nitrenes were determined with high accuracy from spectral simulations. All signals in the EPR spectra of the nitrenes, randomly oriented in the solid phase, were unambiguously assigned based on eigenfield calculations of the Zeeman energy levels and angular dependences of resonance fields. Copyright © 2009 John Wiley & Sons, Ltd. [source]

FTIR Spectroscopic and Theoretical Study of the Photochemistry of Matrix-isolated Coumarin

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007
Nihal Ku
The infrared spectrum of monomeric unsubstituted coumarin (C9H6O2; 2H -1-benzopyran-2-one), isolated in solid argon at 10 K is presented and assigned. The UV-induced (, > 200 nm) unimolecular photochemistry of the matrix-isolated compound was studied experimentally. Three main photoreactions were observed: (a) decarboxylation of the compound and formation of benzocyclobutadiene and CO2, with the Dewar form of coumarin as intermediate; (b) isomerization of the compound, leading to production of a conjugated ketene; and (c) decarbonylation, leading to formation of CO and benzofuran complex. Further decomposition of benzofuran to produce ethynol is suggested. Photochannels (a) and (b) correspond to those previously observed for matrix-isolated ,- pyrone and its sulfur analogs (Phys. Chem. Chem. Phys. 2004, 6, 929; J. Phys. Chem. A 2006, 110, 6415), while route (c) is similar to the UV-induced photochemistry of coumarin in the gaseous phase (J. Phys. Chem. A 2000, 104, 1095). Interpretation of the experimental data is supported by extensive calculations performed at the B3LYP/6-311++G(d,p), MP2/6-31G(d,p) and MP2/6-311++G(d,p) levels. [source]