Spectroscopic identification of 2,4-pyrimidinedithiol; an experimental matrix isolation and ab initio Hartree-Fock and density functional theory study.

L Lapinski, M J Nowak, R Kołos, J S Kwiatkowski, J Leszczyński

Index: Spectrochim. Acta. A. Mol. Biomol. Spectrosc. 54A(5) , 685-93, (1998)

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Abstract

2,4-Pyrimidinedithiol (the dithiol form of 2,4-dithiouracil) was generated by UV (lambda > 335 nm) irradiation of the dithione form of 2,4-dithiouracil isolated in low-temperature argon or nitrogen matrices. The IR and UV spectra of the photoproduct are reported. The dithiol form of 2,4-dithiouracil was identified by comparison of the experimental spectrum with the spectrum theoretically predicted for this form at the HF/6-31 (d,p) and DFT(B-3LYP)/6-31 (d,p) levels. This comparison resulted also in assignment of the bands observed in the IR spectrum of 2,4-pyrimidinedithiol to the theoretically predicted normal modes.