共查询到20条相似文献,搜索用时 15 毫秒
1.
Chiappero MS Argüello GA Garcia P Pernice H Willner H Oberhammer H Peterson KA Francisco JS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(4):917-924
The molecular structure of FC(O)I has been determined by gas electron diffraction. High-level ab initio methods, including coupled-cluster and the new correlation-consistent basis sets for fourth row elements, have been used to calculate the structure of FC(O)I. A comprehensive vibrational spectroscopic study (both IR and Raman) complemented by high-level calculations has also been performed. Furthermore, UV, mass, and NMR spectra have been recorded for FC(O)I. The matrix photochemistry of FC(O)I has been studied with a low-pressure mercury lamp and with a high-pressure xenon lamp in combination with interference and cut-off filters. UV photolysis revealed the formation of the OC. IF and OC.FI complexes and further photolysis of these complexes at lambda>320 nm resulted in a re-formation of FC(O)I. The structural conformation of the complexes has been characterized by comparing shifts in their CO and IF vibrational modes with respect to those of the free species. The structures, vibrational properties, and stability of the complexes were analyzed with the aid of coupled-cluster ab initio calculations. 相似文献
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Romano RM Della Védova CO Downs AJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(29):8185-8192
Matrix-isolation experiments have afforded the means of preparing the hitherto unknown sulfur(II) fluoride, methanesulfenyl fluoride, CH3SF. Broadband UV-visible irradiation of methyl thiofluoroformate, FC(O)SCH3, isolated in a solid Ar matrix results, first, in photoisomerization of the syn into the anti form of the molecule, and, subsequently, in the elimination of CO with the concomitant formation of CH3SF. Continued irradiation brings about tautomerization of this product with the detachment and migration of a hydrogen from the methyl group to give the molecular complex H2C==S...HF. The changes have been monitored and the photoproducts detected and identified by the IR spectra of the matrices, and the conclusions confirmed: 1) with reference to the corresponding behavior of the perdeuterated molecule FC(O)SCD3; 2) by analogy with the properties of related molecules, for example, ClC(O)SCH3, CH3SCl, and H2C==S...HCl, and; 3) by comparison with the vibrational properties simulated for the different molecules by ab initio and density functional theory methods. 相似文献
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Gómez Castaño JA Picone AL Romano RM Willner H Della Védova CO 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(33):9355-9361
The photochemically induced reaction of OCSe and F(2), isolated together in an Ar matrix at about 15 K, leads to formation of the hitherto-unknown fluorocarbonylselenyl fluoride FC(O)SeF. The reaction occurs via a van der Waals complex O=C=Se...F-F that favors very early formation of the anti conformer. The presence and subsequent decay of a band assigned to the F-F vibration correlated with perturbed OCSe bands seems to confirm this hypothesis. Subsequent irradiation of the matrix leads to randomized FC(O)SeF by a photochemically induced conformational equilibrium between syn and anti forms. Another photochemical reaction channel is the formation of CO and SeF(2) molecules, which are produced in the same matrix cage and then form a loose complex. The changes were monitored and the products characterized experimentally by their IR spectra, and the spectra analyzed in the light of the results of theoretical calculations. 相似文献
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von Ahsen S García P Willner H Burgos Paci M Argüello GA 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(20):5135-5141
The open-chain trioxide CF(3)OC(O)OOOC(O)OCF(3) is synthesised by a photochemical reaction of CF(3)C(O)OC(O)CF(3), CO and O(2) under a low-pressure mercury lamp at -40 degrees C. The isolated trioxide is a colourless solid at -40 degrees C and is characterised by IR, Raman, UV and NMR spectroscopy. The compound is thermally stable up to -30 degrees C and decomposes with a half-life of 1 min at room temperature. Between -15 and +14 degrees C the activation energy for the dissociation is 86.5 kJ mol(-1) (20.7 kcal mol(-1)). Quantum chemical calculations have been performed to support the vibrational assignment and to discuss the existence of rotamers. 相似文献
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Xiaoqing Zeng Dr. Helmut Beckers Dr. Helge Willner Prof. Dr. Patrik Neuhaus Dirk Grote Dr. Wolfram Sander Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(48):13466-13473
Triplet difluorophosphoryl nitrene F2P(O)N (X3A′′) was generated on ArF excimer laser irradiation (λ=193 nm) of F2P(O)N3 in solid argon matrix at 16 K, and characterized by its matrix IR, UV/Vis, and EPR spectra, in combination with DFT and CBS‐QB3 calculations. On visible light irradiation (λ>420 nm) at 16 K F2P(O)N reacts with molecular nitrogen and some of the azide is regenerated. UV irradiation (λ=255 nm) of F2P(O)N (X3A′′) induced a Curtius‐type rearrangement, but instead of a 1,3‐fluorine shift, nitrogen migration to give F2PON is proposed to be the first step of the photoisomerization of F2P(O)N into F2PNO (difluoronitrosophosphine). Formation of novel F2PNO was confirmed with 15N‐ and 18O‐enriched isotopomers by IR spectroscopy and DFT calculations. Theoretical calculations predict a rather long P? N bond of 1.922 Å [B3LYP/6‐311+G(3df)] and low bond‐dissociation energy of 76.3 kJ mol?1 (CBS‐QB3) for F2PNO. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1994,50(5):897-902
Vibrational data of vapour, liquid and matrix-isolated fluorocarbonyl isocyanate, FC(O)NCO, were investigated. A subsequent normal coordinate analysis was performed for the A′ species of the predominant planar cis conformer (CO double bond cis with respect to the vicinal NC double bond). The following internal force constants were derived: fCO= 12.88 mdyn Å−1, fCF=6.20 mdyn Å−1 and FCN= 4.42 mdyn Å−1. 相似文献
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Direct Observation of an Imidoylnitrene: Photochemical Formation of PhC(=NMe)−N and Me−N from 1‐Methyl‐5‐phenyltetrazole 下载免费PDF全文
Prof. Dr. Manabu Abe Prof. Dr. Didier Bégué Hugo Santos‐Silva Prof. Dr. Alain Dargelos Prof. Dr. Curt Wentrup 《Angewandte Chemie (International ed. in English)》2018,57(12):3212-3216
The imidoylnitrene 8 , N‐methyl‐C‐phenylimidoylnitrene, has been generated by laser photolysis of 1‐methyl‐5‐phenyltetrazole 6 at 5 K and characterized by its ESR spectrum (|D/hc|=0.9602, |E/hc|=0.0144 cm?1). In addition, the triplet excited states of 6 and of 2‐methyl‐5‐phenyltetrazole 11 were also observed by ESR spectroscopy in the 5 K matrices ( 6 : |D/hc|=0.123 cm?1, E/hc=0.0065 cm?1, 11 : |D/hc|=0.126 cm?1, |E/hc|=0.0056 cm?1). The imidoylnitrene 8 is unstable both thermally (disappearing at 80 K) and photochemically (disappearing on continued irradiation at 266 nm). Methyl(phenyl)carbodiimide is the end product of photolysis. 相似文献
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Dr. Sergei V. Chapyshev Dr. Enrique Mendez-Vega Prof. Dr. Wolfram Sander 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(4):1258-1269
Among all C-, N-, and O-centered polyradicals, high-spin nitrenes possess the largest magnetic anisotropy and are of considerable interest as multi-level molecular spin systems for exploration of organic molecular magnetism and quantum information processing. Although the first representatives of quintet and septet nitrenes were obtained almost 50 years ago, the experimental and theoretical studies of these highly reactive species became possible only recently, owing to new achievements in molecular spectroscopy and computational chemistry. Meanwhile, dozens of various quintet dinitrenes and septet trinitrenes were successfully characterized by IR, UV/Vis, and EPR spectroscopy, thus providing important information about the electronic structure, magnetic properties and reactivity of these compounds. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(7):1065-1072
Bis(fluorocarbonyl)trisulphide, FC(O)SSSC(O)F, was prepared both by reaction of FC(O)SCl with H2S and by ultraviolet irradiation of FC(O)SSC(O)F. Infrared data for the vapour, liquid and matrices (in Ar, Ne and N2), as well as Raman, u.v. mass and 19F and 13C NMR spectra have been obtained and interpreted. Complementary measurements were also carried out to determine the dipole moment of the liquid substance.From these data, the most stable conformer was deduced to have a trans conformation of the FC(O) groups with respect to the SSS plane, with both CO bonds syn to the SS bonds. 相似文献
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Light‐Induced Ruthenium‐Catalyzed Nitrene Transfer Reactions: A Photochemical Approach towards N‐Acyl Sulfimides and Sulfoximines 下载免费PDF全文
Dr. Vincent Bizet Laura Buglioni Prof. Dr. Carsten Bolm 《Angewandte Chemie (International ed. in English)》2014,53(22):5639-5642
1,4,2‐Dioxazol‐5‐ones are five‐membered heterocycles known to decarboxylate under thermal or photochemical conditions, thus yielding N‐acyl nitrenes. Described herein is a light‐induced ruthenium‐catalyzed N‐acyl nitrene transfer to sulfides and sulfoxides by decarboxylation of 1,4,2‐dioxazol‐5‐ones at room temperature, thus providing direct access to N‐acyl sulfimides and sulfoximines under mild reaction conditions. In addition, a one‐pot sulfur imidation/oxidation sequence catalyzed by a single ruthenium complex is reported. 相似文献
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Artur Mardyukov Andr K. Eckhardt Peter R. Schreiner 《Angewandte Chemie (International ed. in English)》2020,59(14):5577-5580
We present the first spectroscopic identification of hitherto unknown 1,1‐ethenediol, the enol tautomer of acetic acid. The title compound was generated in the gas phase through flash vacuum pyrolysis of malonic acid at 400 °C. The pyrolysis products were subsequently trapped in argon matrices at 10 K and characterized spectroscopically by means of IR and UV/Vis spectroscopy together with matching its spectral data with computations at the CCSD(T)/cc‐pCVTZ and B3LYP/6–311++G(2d,2p) levels of theory. Upon photolysis at λ=254 nm, the enol rearranges to acetic acid and ketene. 相似文献
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Ultraviolet Photolysis Studies on XeO4 in Noble‐Gas and F2 Matrices and the Formation and Characterization of a New XeVIII Oxide, (η2‐O2)XeO3 下载免费PDF全文
Thomas Vent‐Schmidt James T. Goettel Prof. Dr. Gary J. Schrobilgen Prof. Dr. Sebastian Riedel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11244-11252
The photolytic behavior of the thermochemically unstable xenon(VIII) oxide XeO4 was investigated by UV irradiation in noble‐gas and F2 matrices. Photolysis of Xe16O4 or Xe18O4 in noble‐gas matrices at 365 nm yielded XeO3 and a new xenon(VIII) oxide, namely, (η2‐O2)XeO3, which, along with XeO4, was characterized by matrix‐isolation IR spectroscopy and quantum‐chemical calculations. Calculations of the UV spectrum showed that the photodecomposition is induced by an n→σ* transition, but the nature of the excitation differs when different light sources are used. There is strong evidence for the formation of mobile 1D excited O atoms in the case of excitation at 365 nm, which led to the formation of (η2‐O2)XeO3 by reaction with XeO4. Matrix‐isolation IR spectroscopy in Ne and Ar matrices afforded the natural‐abundance xenon isotopic pattern for the ν3(T2) stretching mode of Xe16O4, and 18O enrichment provided the 16O/18O isotopic shifts of XeO4 and (η2‐O2)XeO3. 相似文献
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Artur Mardyukov Felix Keul Peter R. Schreiner 《Angewandte Chemie (International ed. in English)》2020,59(30):12445-12449
The structures and reactivities of organic phosphinidene chalcogenides have been mainly inferred from trapping or complexation experiments. Phosphinidene chalcogenide derivatives appear to be an elusive family of molecules that have been suggested as reactive intermediates in multiple organophosphorus reactions. The quest to isolate “free” phosphinidene chalcogenides remains a challenge in the field. Here, we present the synthesis, IR, and UV/Vis spectroscopic identification of hitherto elusive phenylphosphinidene oxide and phenylphosphinidene sulfide from the corresponding phosphonic diazide precursors. We isolated these higher congeners of nitroso‐ and thionitrosobenzene in argon matrices at 10 K. The spectral assignments are supported by B3LYP/6–311++G(3df,3pd) and MP2/cc‐pVTZ computations. 相似文献
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Dr. Artur Mardyukov Felix Keul Prof. Dr. Peter R. Schreiner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(30):12545-12549
The structures and reactivities of organic phosphinidene chalcogenides have been mainly inferred from trapping or complexation experiments. Phosphinidene chalcogenide derivatives appear to be an elusive family of molecules that have been suggested as reactive intermediates in multiple organophosphorus reactions. The quest to isolate “free” phosphinidene chalcogenides remains a challenge in the field. Here, we present the synthesis, IR, and UV/Vis spectroscopic identification of hitherto elusive phenylphosphinidene oxide and phenylphosphinidene sulfide from the corresponding phosphonic diazide precursors. We isolated these higher congeners of nitroso- and thionitrosobenzene in argon matrices at 10 K. The spectral assignments are supported by B3LYP/6–311++G(3df,3pd) and MP2/cc-pVTZ computations. 相似文献
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