Generation and Microwave Spectrum oftrans-1-Chloro-2-nitrosoethene, ClCH=CH—N=O

✍ Scribed by Takeshi Sakaizumi; Motoi Nishikawa; Osamu Ohashi

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 294 KB
• Volume: 178
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1996.0164

✦ Synopsis

trans-1-Chloro-2-nitrosoethene, ClCH|CH{NO (syn form: 8 in Fig. 1), has been generated in the gas phase from 1,1-dichloro-2-(hydroxyimino)ethane by pyrolysis or by chemical reaction of the precursor with NaHCO 3 and identified by microwave spectroscopy. The microwave spectrum has been observed in the frequency range from 8.0 to 40.0 GHz. The rotational constants (MHz) have been determined as A Å 38 935 (147), B Å 1519.056 (6), and C Å 1461.595 (6) for trans-35 ClCH|CHNO ( 35 Cl species) and A Å 38 546 (81), B Å 1481.667 (3), and C Å 1426.835 (3) for trans-37 ClCH|CHNO ( 37 Cl species). The observed inertial defects of the 35 Cl and 37 Cl species were found to be 00.099 (51) and 00.003 (30) u A ˚2, respectively. The nuclear quadrupole coupling constants (MHz) were determined to be x aa Å 050.4 (21) and x bb Å 31.1 (63) MHz for the 35 Cl species, and x aa Å 040.9 (10) and x bb Å 27.7 ( 22) MHz for the 37 Cl species. One vibrationally excited state was observed and assigned to the C-N torsional mode [120 (30) cm 01 ] that was almost harmonic. The observed pyrolysate was determined to be trans-1-chloro-2-nitrosoethene by comparing the observed and calculated rotational constants and coordinates of the chlorine atom. The r 0 structural parameters of r(C{Cl) and r(C|C) and bond angle of Cl{C{C were determined by fitting them to the observed rotational constants. Interesting reaction products, such as formyl chloride and hydrogen cyanide, were also detected during the pyrolysis of the precursor. The lifetime of trans-1-chloro-2-nitrosoethene is ca. 1 min in the waveguide cell.