Generation, spectroscopy, and structure of cyanoformyl chloride and cyanoformyl bromide, XC(O)CN.

Cyanoformyl chloride and cyanoformyl bromide, XC(O)CN (X = Cl and Br), have been investigated in the gas phase by UV photoelectron and mid-infrared spectroscopies. The ground-state geometries of the neutral molecules have been obtained from quantum-chemical calculations at the B3LYP and CCSD(T) levels using the aug-cc-pVTZ basis set. The individual spectroscopies provide a detailed investigation into the vibrational and electronic character of the molecules and are supported by quantum-chemical calculations.

Dimerisation of nitrile oxides: a quantum-chemical study.

The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH(3)) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation.

Synthesis, spectroscopy and structure of the parent furoxan (HCNO)2.

The parent furoxan (1,2,5-oxadiazole 2-oxide), synthesized from glyoxime and NO(2)(g), has been investigated in the gas phase for the first time by mid-infrared and He I photoelectron spectroscopy, and in the liquid phase by Raman spectroscopy. The ground-state geometry has been obtained from quantum-chemical calculations at the B3LYP, MPn (n = 2-4), CISD, QCISD, CCSD, CCSD(T), RSPTn (n = 2,3), MRCI, and MR-AQCC levels using 6-311++G(2d,2p), cc-pVTZ, aug-cc-pVTZ, cc-pCVTZ, and cc-pVQZ basis sets. Furoxan is predicted to be planar, with a strong exocyclic and a relatively weak endocyclic N-O bond.

Gas-phase infrared and ab initio study of the unstable CF3CNO molecule and its stable furoxan ring dimer.

The unstable trifluoroacetonitrile N-oxide molecule, CF3CNO, has been generated in high yield in the gas phase from CF3BrC=NOH and studied for the first time by gas-phase mid-infrared spectroscopy. Cold trapping of this molecule followed by slow warming forms the stable ring dimer, bis(trifluoromethyl)furoxan, also investigated by gas-phase infrared spectroscopy. The spectroscopy provides an investigation into the vibrational character of the two molecules, the assignments supported by calculations of the harmonic vibrational frequencies using in the case of CF3CNO both ab initio (CCSD(T)) and density functional theory (B3LYP) and B3LYP for the ring dimer.

Resonance-enhanced multiphoton ionisation photoelectron spectroscopy of the ClO radical: the C 2 sigma- state.

A (2 + 1) one-colour resonance-enhanced multiphoton ionisation study is carried out on the C 2 sigma- state of the ClO radical in the one-photon energy range 29,500-31,250 cm-1. The ClO radical is produced by one-photon photolysis of ClO2 employing 359.2 nm photons derived from a separate laser.