Insights into cisplatin binding to uracil and thiouracils from IRMPD spectroscopy and tandem mass spectrometry
The monofunctional primary complexes cis-[PtCl(NH3)2(L)]+, formed by the reaction of cisplatin, a major chemotherapeutic agent, with four nucleobases L, i.e., uracil (U), 2-thiouracil (2SU), 4-thiouracil (4SU), and 2,4-dithiouracil (24dSU), have been studied by a combination of infrared multiple photon dissociation (IRMPD) action spectroscopy in both the fingerprint (900-1900 cm-1) and the N-H/O-H stretching (3000-3800 cm-1) ranges, energy-resolved collision-induced dissociation (CID) mass spectrometry, and density functional calculations at the B3LYP/LACVP/6-311G** level.