Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/91502
Title: He I and He II photoelectron spectra of γ-thionobutyrolactones and γ-butyrolactones
Authors: Pan, J.F. 
Huang, W. 
Chin, W.S. 
Huang, H.H. 
Mok, C.Y. 
Keywords: Butyrolactones
HeI/HeII spectra
Ionization potentials
MO calculations
PES
Thionobutyrolactones
Issue Date: Mar-1998
Citation: Pan, J.F.,Huang, W.,Chin, W.S.,Huang, H.H.,Mok, C.Y. (1998-03). He I and He II photoelectron spectra of γ-thionobutyrolactones and γ-butyrolactones. Journal of Electron Spectroscopy and Related Phenomena 88-91 : 91-96. ScholarBank@NUS Repository.
Abstract: The valence electronic structures of the compounds γ-thionobutyrolactone (X=S, Y=O, R = R″ = H), γ-butyrolactone (X=O, Y=O, R = R″ = H) and their respective 3-and 5-methyl-substituted derivatives have been investigated by photoelectron spectroscopy. Two distinct bands are observed in the ionization potential (IP) range 8-11 eV in the spectra of all these compounds, with the first ionization band exhibiting clear vibrational progressions. Variation in the He I/He II relative intensities in the spectra of the γ-thionobutyrolactones suggests the assignment of the first band to the lone-pair ns orbital, the second band to the π*OCS orbital and the third band to the πOCS orbital. The first two bands in the spectra of the γ-butyrolactones, on the other hand, are ascribed to the nO(C=O) and the ethereal nO(π) orbitals, respectively. The assignments are aided by the results from semi-empirical PM3 and ab initio calculations using the 6-31G** basis sets. Correlation with the IPs of thioformaldehyde, cyclopentanone and tetrahydrofuran indicates that the interaction between the carbonyl group and the ring oxygen atom is mainly inductive in nature. In the γ-thionobutyrolactones, the conjugative interaction is more significant. Methyl substitution causes mainly inductive effects on the parent heterocyclics. © 1998 Elsevier Science B.V.
Source Title: Journal of Electron Spectroscopy and Related Phenomena
URI: http://scholarbank.nus.edu.sg/handle/10635/91502
ISSN: 03682048
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

36
checked on Sep 21, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.