An Ab Initio density functional study of the structure and stability of transition metal ozone complexes

[摘要] ENGLISH ABSTRACT:A thorough search through the literature as well as through the Cambridge CrystallographicStructural Database resulted in no examples of a neutral ozone acting as ligand in a complexwith any metal. Ionic compounds containing ozonide as anionic species, however, are wellknown throughout the literature and not surprisingly the only result for 0₃ and a metal in theCCSD was an ionic rubidium ozonide compound.What follows is a systematic study into the result of placing an ozone ligand withincomplexing distance of a transition metal (the first transition row from titanium to copper). Dueto the novelty of the system, as first approximation four different orientations of the ozone ligandrelative to the metal (a metal cation in these calculations) were investigated. It was found thatcoordination through the terminal oxygens resulted in energy minima for all the metal cations,although not necessarily the absolute energy minimum on the potential energy surface for thespecific cation. A further structural study was done by adding carbonyl and hydrogen ligands tothe system, according to the 18-electron rule. For these calculations coordination through theterminal oxygens was employed. In both series the dissociation energy was also calculated. Thedissociation energies for the M(CO)nHm(0₃) complexes were all positive, indicating that they aretheoretically stable structures.The resulting wave functions were then analysed with the help of three techniques: Atomsin Molecules (AIM), Charge Decomposition Analysis (CDA) and Natural Bond Orbital Analysis(NBO). AIM showed that bonds were indeed formed between the ozone ligand and the transitionmetal and hinted that the bonding model can be interpreted with the Dewar-Chatt-Duncanson(DCD) model of σ-donation and л-back donation. CDA confirmed that this was the case. NBOresults proved erroneous due to the largely delocalized electronic structure of the complexes.

[发布机构] Stellenbosch University