Attempted generation of the NSNCO molecule via an NSCl(g)/AgNCO(s) reaction leads to the formation of a gaseous product identified as S2N2CO. This molecule is characterized by He I photoelectron spectroscopy employing a position sensitive detector, photoionization (He I, HL(alpha)) mass spectroscopy, and mid-infrared spectroscopy, as a planar five-membered ring with alternating S and N atoms, and an exocyclic carbonyl group. Previous synthetic work has identified this species as a yellow crystalline solid; the present study is aimed at elucidating gas-phase information. The electronic and geometric structures obtained from semiempirical (MNDO, PM3), and ab initio (6-31G*) calculations establish the cyclic structure, with the observed gas-phase ionization potentials and vibrational frequencies in close correspondence to theory.
Roesky’s Ketone: Structure, Aromaticity and Reactivity
作者:Joris Van Droogenbroeck、Karla Tersago、Christian Van Alsenoy、Stephen M. Aucott、Heather L. Milton、J. Derek Woollins、Frank Blockhuys
DOI:10.1002/ejic.200400361
日期:2004.10
and crystal structure of the title compound, 5-oxo-1,3,2,4-dithiadiazole or Roesky’sketone (1), is studied experimentally by re-determining the crystal structure and theoretically by calculations at the density functional level of theory using an extended basis set. A comprehensive set of properties, consisting of orbital topologies, atomic charges, atomic and molecular dipoles, aromaticity parameters