Contrasting behavior in azide pyrolyses:: An investigation of the thermal decompositions of methyl azidoformate, ethyl azidoformate and 2-azido-N, N-dimethylacetamide by ultraviolet photoelectron spectroscopy and matrix isolation infrared spectroscopy

被引:36
作者
Dyke, JM [1 ]
Levita, G
Morris, A
Ogden, JS
Dias, AA
Algarra, M
Santos, JP
Costa, ML
Rodrigues, P
Andrade, MM
Barros, MT
机构
[1] Univ Southampton, Dept Chem, Southampton SO17 1BJ, Hants, England
[2] Univ Nova Lisboa, Dept Phys, Fac Ciencias & Tecnol, CEFITEC, P-2829215 Caparica, Portugal
[3] Univ Nova Lisboa, Dept Chem, Fac Ciencias & Tecnol, CQFB, P-2829215 Caparica, Portugal
关键词
azides; IR spectroscopy; matrix isolation; photoelectron spectrosopy;
D O I
10.1002/chem.200400767
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The thermal decompositions of methyl azidoformate (N3COOMe), ethyl azidoformate (N3COOEt) and 2-azido-N,N-dimethylacetamide (N3CH2CONMe2) have been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. N-2 appears as an initial pyrolysis product in all systems, and the principal interest lies in the fate of the accompanying organic fragment. For methyl azidoformate, four accompanying products were observed: HNCO, H2CO, CH2NH and CO2, and these are believed to arise as a result of two competing decomposition routes of a four-membered cyclic intermediate. Ethyl azidoformate pyrolysis yields four corresponding products: HNCO, MeCHO, MeCHNH and CO2, together with the five-membered-ring compound 2-oxazolidone. In contrast, the initial pyrolysis of 2-azido-N,N-dimethyl acetamide, yields the novel imine intermediate Me2NCOCH=NH, which subsequently decomposes into dimethyl formamide (HCONMe2), CO, Me2NH and HCN. This intermediate was detected by matrix isolation IR spectroscopy, and its identity confirmed both by a molecular orbital calculation of its IR spectrum, and by the temperature dependence and distribution of products in the PES and IR studies. Mechanisms are proposed for the formation and decomposition of all the products observed in these three systems, based on the experimental evidence and the results of supporting molecular orbital calculations.
引用
收藏
页码:1665 / 1676
页数:12
相关论文
共 27 条
[1]  
[Anonymous], 1971, MOL PHOTOELECTRON SP
[2]   A multiconfigurational self-consistent field study of the thermal decomposition of methyl azide [J].
Arenas, JF ;
Marcos, JI ;
Otero, JC ;
Sánchez-Gálvez, A ;
Soto, J .
JOURNAL OF CHEMICAL PHYSICS, 1999, 111 (02) :551-561
[3]   OPTICAL AND PHOTOELECTRON SPECTRA OF SMALL RINGS .3. SATURATED 3-MEMBERED RINGS [J].
BASCH, H ;
ROBIN, MB ;
KUEBLER, NA ;
BAKER, C ;
TUNER, DW .
JOURNAL OF CHEMICAL PHYSICS, 1969, 51 (01) :52-+
[4]   ANALYSIS AND OPTIMIZATION OF GAS-PHASE REACTIONS .18. THE PYROLYSIS OF METHYL AZIDE [J].
BOCK, H ;
DAMMEL, R ;
HORNER, L .
CHEMISCHE BERICHTE-RECUEIL, 1981, 114 (01) :220-226
[5]   GAS-PHASE PYROLYSES OF ALKYL AZIDES - GAS-PHASE REACTION .68. EXPERIMENTAL-EVIDENCE FOR CHEMICAL ACTIVATION [J].
BOCK, H ;
DAMMEL, R .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1988, 110 (16) :5261-5269
[6]   GAS-PHASE REACTIONS .36. PYROLYSIS OF VINYL AZIDE [J].
BOCK, H ;
DAMMEL, R ;
AYGEN, S .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1983, 105 (26) :7681-7685
[7]  
Bock H., 1987, ANGEW CHEM, V99, P518
[8]   HIGH-TEMPERATURE FURNACE FOR USE IN PHOTOELECTRON-SPECTROSCOPY [J].
BULGIN, D ;
DYKE, J ;
GOODFELLOW, F ;
JONATHAN, N ;
LEE, E ;
MORRIS, A .
JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA, 1977, 12 (01) :67-76
[9]  
DAMMEL R, 1985, THESIS U FRANKFURT M
[10]  
DIANXUN W, COMMUNICATION