Efficient Hydrogenolysis of Alkanes at Low Temperature and Pressure Using Tantalum Hydride on MCM‐41, and a Quantum Chemical Study

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/SiO2, featuring well-defined [≡SiOHf(CH2 tBu)2(μ-H)3IrCp*] surface sites. Unlike the monometallic analogous materials Hf/SiO2 and Ir/SiO2, which promote n-pentane deuterogenolysis through C-C bond scission, we demonstrate that under the same experimental conditions (1 bar D2, 250 °C, 3 h, 0.5 mol %), the heterobimetallic catalyst HfIr/SiO2 is highly efficient and selective for the perdeuteration of alkanes with D2, exemplified on n-pentane, without substantial deuterogenolysis (<2 % at 95 % conversion). Furthermore this HfIr/SiO2 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(sp3)-H bonds.

Titanium methyl tamed on silica: synthesis of a well-defined pre-catalyst for hydrogenolysis of n-alkane

Alkylation of Ti(CH₃)₂Cl₂1 by MeLi gives the homoleptic Ti(CH₃)₄2 for the first time in the absence of any coordinating solvent. The reaction of 2 with silica pretreated at 700 °C (SiO_2-700) gives two inequivalent silica-supported Ti-methyl species 3. Complex 3 was characterized by IR, microanalysis (ICP-OES, CHNS, and gas quantification), and advanced solid-state NMR spectroscopy (¹H, ¹³C, DQ, TQ, and HETCOR). The catalytic activity of the pre-catalyst 3 is investigated in low-temperature hydrogenolysis of propane and n-butane with TONs of 419 and 578, respectively.