We present here a study based on Density Functional Theory (DFT) calculations, to contribute to the understanding of the complexes behavior based on tungsten carbonyls ([W(C7H7NS)(CO)5], [W ( C3H6N2S)(CO)5 ] ), which consider as targets molecules of biological interest and easily detectable probes by IR spectroscopy. The results showed good agreements between the calculated and experimental values of the geometric parameters for the two complexes. A peak in the IR spectrum at 2030 cm-1 is due to the stretching of the C-O triple bond, according to the AIM analysis (0.07<ρ<0.15 ), the existence of an intermediate interaction between the tungsten and the CO ligand. Moreover, these complexes are stable, the spectra of TD-DFT analysis showed these complexes absorb in the same domain of wavelengths, through absorption features at about 110-160 nm, characterized by natural transitions of HOMO/LUMO; of type MLCT for both complexes.