SPECTROSCOPIC IDENTIFICATION OF 2,4-PYRIMIDINEDITHIOL - AN EXPERIMENTAL MATRIX-ISOLATION AND AB-INITIO HARTREE-FOCK AND DENSITY-FUNCTIONAL THEORY STUDY

2,4-Pyrimidinedithiol (the dithiol form of 2,4-dithiouracil) was gener ated by UV (lambda > 335 nm) irradiation of the dithione form of 2,3-d ithiouracil isolated in low-temperature argon or nitrogen matrices. Th e 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 th e HF/6-31 (d,p) and DFT(B-3LYP)/6-31 (d,p) levels. This comparison res ulted also in assignment of the bands observed in the IR spectrum of 2 ,4-pyrimidinedithiol to the theoretically predicted normal modes. (C) 1998 Elsevier Science B.V. All rights reserved.