Unprecedented flexibility of the >Ti=Si< group for the addition of H2

Phys Chem Chem Phys. 2007 Jun 7;9(21):2706-12. doi: 10.1039/b617521j. Epub 2007 Mar 6.

Abstract

We show using DFT calculations that a coordinatively unsaturated >Ti=Si< group exhibits an unprecedented flexibility for the reversible addition of dihydrogen. The H2 attachment may lead to a variety of hydrogenated species (near-equivalent in energy), which contain three-center Ti...H...Si and terminal Ti-H and Si-H bonds. The >Ti=Si< moiety also exhibits a particularly low electronic barrier for heterolytic H2 attachment (approximately 0.0 eV) and beneficial thermodynamics of this process. One important path leads to the kinetically preferred H-Ti...H...Si isomer (at -0.5 eV with respect to the substrates, denoted II), which is capable of a subsequent low-barrier H2 release. Chemically pre-engineered compounds containing the >Ti=Si< grouping might be used for efficient H2 transfer catalysis in organic and inorganic hydrogenations, and for charging/discharging of the hydrogen storage materials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Computer Simulation
  • Hydrogen / chemistry*
  • Models, Chemical
  • Quantum Theory
  • Silicon / chemistry*
  • Surface Properties
  • Titanium / chemistry*

Substances

  • Hydrogen
  • Titanium
  • Silicon