Infrared absorption of gaseous ClCS detected with time-resolved Fourier-transform spectroscopy.
A transient infrared absorption spectrum of gaseous ClCS was detected with a step-scan Fourier-transform spectrometer coupled with a multipass absorption cell. ClCS was produced upon irradiating a flowing mixture of Cl2CS and N2 or CO2 with a KrF excimer laser at 248 nm. A transient band in the region of 1160-1220 cm-1, which diminished on prolonged reaction, is assigned to the C-S stretching (nu1) mode of ClCS. Calculations with density-functional theory (B3P86 and B3LYP/aug-cc-pVTZ) predict the geometry, vibrational wave numbers, and rotational parameters of ClCS. The rotational contour of the spectrum of ClCS simulated based on predicted rotational parameters agrees satisfactorily with experimental observation; from spectral simulation, the band origin is determined to be at 1194.4 cm-1. Reaction kinetics involving ClCS, CS, and CS2 are discussed.
Ab initio SCF MO calculations of the potential surfaces of thiocarbonyls. II. H2CS, HFCS, CIFCS, and Cl2CS
Potential energy surfaces and equilibrium geometries for the ground and first excited triplet states of H2CS, HFCS, ClFCS, and Cl2CS have been calculated using ab initio SCF MO methods. The triplet state out‐of‐plane bending mode frequencies have been calculated using a perturbation theoretical treatment and a suitable analytic approximation to the potential along the out‐of‐plane bending coordinate. Where experimental results are available, good agreement exists between calculated and experimental data. The equilibrium out‐of‐plane angle in the lowest triplet state is correlated with the decrease in the p electron density on the carbon atom accompanying the change from the planar to the equilibrium out‐of‐plane conformation.
Lupin alkaloids from teratogenic and nonteratogenic lupins. II. Identification of the major alkaloids by tandem gas chromatography-mass spectrometry in plants producing crooked calf disease.
The major alkaloids of lupin plants producing crooked calf disease were identified by tandem gas chromatography-mass spectrometry and infrared analysis. The gas chromatography peak invariably present in teratogenic plants proved to be anagyrine. A minor but irregular contaminant of the peak was α-isolupanine. Other alkaloids present but apparently not associated with crooked calf disease were lupanine and two others that were probably epimethoxylupanine and 5,6-dehydrolupanine.