On the Nature of Actinide- and Lanthanide-Metal Bonds in Heterobimetallic Compounds

Eleven experimentally characterized complexes containing heterobimetallic bonds between elements of the f-block and other elements were examined by quantum chemical methods: [(eta(5)-C5H5)(2)(THF)LuRu(eta(5)-C5H5)(CO)(2)], [(eta(5)-C5Me5)(2)(I)ThRu(eta(5)-C5H5)(CO)(2)], [(eta(5)-C5H5)(2)YRe(eta(5)-C5H5)(2)], [{N(CH2CH2NSiMe3)(3)}URe(eta(5)-C5H5)(2)], [Y{Ga(NArCh)(2)}{C(PPh2NSiH3)(2)}(CH3OCH3)(2)], [{N(CH2CH2NSiMe3)(3)}U{Ga(NArCH)(2)}(THF)], [(eta(5)-C5H5)(3)UGa(eta(5)-C5Me5)], [Yb(eta(5)-C5H5){Si(SiMe3)(3)(THF)(2)}], [(eta(5)-C5H5)(3)U(SnPh3)], [(eta(5)-C5H5)(3)U(SiPh3)], and (Ph[Me]N)(3)USi(SiMe3)(3). Geometries in good agreement with experiment were obtained at the density functional level of theory. The multi-configurational complete active space self-consistent field method (CASSCF) and subsequent corrections with second order perturbation theory (CASPT2) were applied to further understand the electronic structure of the lanthanide/actinide-metal (or metal-metalloid) bonds. Fragment calculations and energy-decomposition analyses were also performed and indicate that charge transfer occurs from one supported metal fragment to the other, while the bonding itself is always dominated by ionic character.