title: Fragmentation pathways analysis for the gas phase dissociation of protonated carnosine-oxaliplatin complexes.
abstract: Collision-induced dissociation (CID) experiments on the protonated carnosine-oxaliplatin complex, [Carnosine + OxPt + H](+) using several collision energies were shown to yield nine different fragment ions. Energy-resolved CID experiments on [Carnosine + OxPt + H](+) showed that the generation of the product ion [Carnosine - H + Pt(dach)](+) (where dach is 1,2-diaminocyclohexane) is the lowest energy process. At slightly higher collision energies, the loss of neutral carnosine from [Carnosine + OxPt + H](+) to produce [OxPt + H](+) was observed, followed by the loss of oxaliplatin from the same precursor ion to produce [Carnosine + H](+). At significantly higher energies, the ion [OxPt - CO2 + H](+) was shown to be formed, while the last two investigated ions [Carnosine + OxPt - CO2 + H](+) and [Carnosine - NH3 - H + Pt(dach)](+) did not attain any significant relative abundance. Density functional calculations at the B3LYP/LANL2DZ level were employed to probe the fragmentation mechanisms that account for all experimental data. The lowest free energy barriers for the generation of each of the ions [Carnosine - H + Pt(dach)](+), [OxPt + H](+), [Carnosine + H](+), [Carnosine + OxPt - CO2 + H](+) and [Carnosine - NH3 - H + Pt(dach)](+) from [Carnosine + OxPt + H](+) according to the fragmentation mechanisms offered here were calculated to be 31.9, 38.8, 49.3, 75.2, and 85.6 kcal mol(-1), respectively.
authors.affiliation: Dipartimento di Chimica UniVersita della Calabria, Via P. Bucci, cubo 14c, 87036 Arca Vacata di Rende (CS), Centro di Calcolo ad Alte Prestazioni per Elaborazioni Parallele e Distribuite - Centro d'Eccellenza MIUR, Rende 87036, Italy.
authors.forename: Ida
authors.initials: I
authors.lastname: Ritacco
authors.forename: Eslam M
authors.initials: EM
authors.lastname: Moustafa
authors.forename: Emilia
authors.initials: E
authors.lastname: Sicilia
authors.forename: Nino
authors.initials: N
authors.lastname: Russo
authors.forename: Tamer
authors.initials: T
authors.lastname: Shoeib
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry*; D002336:Carnosine / Q000737:chemistry*; D003514:Cyclohexylamines / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D009944:Organoplatinum Compounds / Q000737:chemistry*; D000077150:Oxaliplatin; D011522:Protons; D013816:Thermodynamics
chemical_list: D000970:Antineoplastic Agents; D003514:Cyclohexylamines; D007477:Ions; D009944:Organoplatinum Compounds; D011522:Protons; D000077150:Oxaliplatin; D002336:Carnosine; C030435:1,2-cyclohexanediamine