Theoretical Investigation Of The Ligand Effects For Iron Ion In The Gas Phase Reactions

Density functional theory has been employed to investigate the reactionmechanisms of the reactions of Fe(CX)+(X=O,S),[FeH(L)]+(L=H2O,OH) with oxygen.We studied all the possible reaction paths. Theoretical calculation makes our reactionmechanisms of these gas reactions should be have a more profound understanding. Bythe theory study, we know we could get only one initial combination when thesecomplexes react with oxygen. For Fe(CO)+, the dominant pathway is the ligandexchange reaction to get the product of FeO2+; Secondary reaction with FeO+and Fe+generated, Fe+get mainly depend on collision excitation, iron insert and then oxygeninsert can explain FeO+generated. For Fe(CS)+complex, due to the relativelystronger bonding energy between Fe+with the CS ligand makes the replacementreaction seldom happened. Iron-medium excitation is one of the main reactionpathway, resulting in FeO+, Fe+and FeS+. The main product of this reaction system isFeO+accompanied by a lot of heat, iron insert and accompanying oxygen insertionmay explain the formation of Fe+. Fe+generated with FeS+generated at the same time,there is competition between relations. According to the theoretical calculation showsthat the [FeH (H2O)]+/O2system, in the singlet state the double oxygen can directlyby the activation of O-O bond inserted into Fe+-H to get a three-ligands intermediatesof the initial combination. However, in the triplet state, the double oxygen by theactivation of O-O bond inserted into Fe+-H to get a hydroperoxide intermediate andafter the Fe+-O-OH folding structure to get a three ligands of intermediates. Byinspection of the potential energy surface, the ground state of this reaction system istriplet, and there is no potential energy surface crossing in the reaction process,reaction in triplet. The H2O and the formation of OH are under adiabatic conditions, gives off heat, and O generation needs to absorb heat. For [FeH (OH)]+/O2system, itsreaction is more complicated than [FeH (H2O)]+/O2system, in the system the processof activation of O-O bond, molecular oxygen inserted into the Fe+-H bond and thestructure of the Fe+-O-OH folding process is also exist, there are also hydrogentransfer. By inspection of the potential energy surface, the system of the main reactionpath is the generation of water molecules, its generated path not only simple, but a lotof heat. The reaction path of the OH generation is relatively simple, but it needs toabsorb heat, and O generated path is the most complex, but the exothermic reaction.So, OH and O generate mutual competition, generated branching ratio close to.