There has been structural analysis of 1-phenyl-3-methyl-2-pirazolin-5-one-4-etoxicarbonil (PirC2) by means of two techniques of two-dimensional NMR, the HSQC and HMBC, which helped to elucidate the interaction between the atoms of carbon and hydrogen present in the organic molecule. It was interacted this compound with a salt of uranyl in order to test the possible formation of the respective complex compound. Using the vibrational spectrum was possible to determine the force constant and the bond length of the uranium and oxygen atoms at the UO2 2+ present in the complex, using the model of Badger modified by Jones.