THE VIBRATIONAL-SPECTRA OF SOME 2-MERCAPTOPYRIMIDINE COMPLEXES OF MERCURY(II)

The IR and Raman spectra of a series of complexes of the type HgX2(2MP ), where X = Cl, Br or I and 2MP = 2-mercaptopyrimidine, have been obt ained in the solid state. The spectra show that all three species poss ess a trans dimeric halogen-bridged structure of C2h molecular symmetr y and that the organic ligand is bonded to mercury by its exocyclic su lfur atom. The above conclusion is also supported by an SCF-MO-MNDO ca lculation on the HgI2(2MP) dimer, which shows that the trans structure is ca 100 kcal/mol more stable than any other intermediate possible s tructure.