Highly Selective and Efficient Perdeuteration of n-Pentane via H/D Exchange Catalyzed by a Silica-Supported Hafnium-Iridium Bimetallic Complex.

A Surface OrganoMetallic Chemistry (SOMC) approach is used to prepare a novel hafnium-iridium catalyst immobilized on silica, HfIr/SiO, featuring well-defined [≡SiOHf(CH Bu)(μ-H)IrCp*] surface sites. Unlike the monometallic analogous materials Hf/SiO and Ir/SiO, which promote n-pentane deuterogenolysis through C-C bond scission, we demonstrate that under the same experimental conditions (1 bar D, 250 °C, 3 h, 0.5 mol %), the heterobimetallic catalyst HfIr/SiO is highly efficient and selective for the perdeuteration of alkanes with D, exemplified on n-pentane, without substantial deuterogenolysis (<2 % at 95 % conversion). Furthermore this HfIr/SiO catalyst is robust and can be re-used several times without evidence of decomposition. This represents substantial advance in catalytic H/D isotope exchange (HIE) reactions of C(sp)-H bonds.