Theoretical explorations on the molecular structure and IR frequencies of 3-phenyl-1-tosyl-1H-pyrazolo[3,4-d]pyrimidin-4-amine in view of experimental results

The electronic structure calculations and vibrational assignments of a biologically important molecule namely, 3-phenyl-1-tosyl-1H-pyrazolo[3,4-d]pyrimidin-4-amine have been carried out through Hartree Fock (HF/6-31G**) and density functional theory (B3LYP/6-31G**) methods. The optimized geometrical parameters, molecular electrostatic potentials (MEP), and HOMO-LUMO gaps as obtained through both methods are compared. Small value of HOMO-LUMO energy gap (~ 0.17687 a.u.), as obtained through both methods, indicate that the molecule is chemically highly reactive and charge transfer occur within the molecule. Further, the vibrational spectra of the molecule calculated through DFT method are assigned and compared with those of the experimental results, reported in literature. The computed vibrational assignments have been found to be fairly in good agreement with experimental values.