A theoretical study on bonding and ener gy aspects of [Ln(D OTA)]- a nd [Ln(DOT A).H۲O]- complex es (Ln=Eu۳+, Ho۳+)

Complexes of trivalent lanthanide ions with the cyclen deri vative ۱,۴ ,۷,۱۰ tetraa zacyclododecane-۱,۴,۷,۱ ۰-tetraacetate (DOTA) and related ligands are of great interest because of their use in various medical applications, such as cancer radiotherapy or ma gnetic resona nce imaging (MRI)[۱,۲ ]. The successful use of these com plexes in medical diag nosis and therapy is par tially related to their high thermodynamic stability and ki netic inertness[۳]. Earlier studies indicated that the Holmi um and Europium complexes of D OTA show nine coordi nation around the metal ion with square antipr ismatic geometry involving four N- and four O - donor at oms of the DOTA liga nd and a co ordination water molec ule in a capping positi on [۴].The aim of the resent work was the quantum chemical description of lanthanide-D OTA intera ctions in [L n(DOTA)]í (Ln = Eu or Ho) complexes. The e ffect of wat er coordination to the [Ln(DOTA)]í complexes is also investigated. For this reason, we have analyzed the L n...O and Ln... characteristics, using the Bade r’s quantum theory of a toms in molecules (QTAIM) and NBO calculations. The st ructural and energy aspects of the co mplexes we re also studied.

کلیدواژه ها:

DFT ، Lanthanides ، DOTA ، w ater bindin g ، NBO