Related Experiment Video
Updated: Jul 1, 2025

Preparation of Functional Silica Using a Bioinspired Method
Published on: August 1, 2018
Formation of Strong Boron Lewis Acid Sites on Silica
Kavyasripriya K Samudrala1, Manjur O Akram2, Jason L Dutton3
1Department of Chemistry, University of California, Riverside, California 92521, United States.
Abstract:
Bis(1-methyl-ortho-carboranyl)borane (HBMeoCb2) is a very strong Lewis acid that reacts with the isolated silanols present on silica partially dehydroxylated at 700 °C (SiO2-700) to form the well-defined Lewis site MeoCb2B(OSi≡) (1) and H2. 11B{1H} magic-angle spinning (MAS) nuclear magnetic resonance (NMR) data of 1 are consistent with that of a three-coordinate boron site. Contacting 1 with O═PEt3 (triethylphosphine oxide TEPO) and measuring 31P{1H} MAS NMR spectra show that 1 preserves the strong Lewis acidity of HBMeoCb2. Hydride ion affinity and fluoride ion affinity calculations using small molecules analogs of 1 also support the strong Lewis acidity of the boron sites in this material. Reactions of 1 with Cp2Hf(13CH3)2 show that the Lewis sites are capable of abstracting methide groups from Hf to form [Cp2Hf-13CH3][H313C-B(MeoCb2)OSi≡], but with a low overall efficiency.
More Related Videos
Related Concept Videos
Hybridization of Atomic Orbitals I
Lewis Acids and Bases
Hydroboration-Oxidation of Alkenes
Lewis Structures of Molecular Compounds and Polyatomic Ions
VSEPR Theory and the Basic Shapes
Exceptions to the Octet Rule

