Adamantyl Modified Silica via Olefin Hydrosilation on a Hydride Intermediate

Abstract

Adamantyl‐containing reversed phase (RP) bonded materials were prepared by applying catalytic olefin hydrosilylation as the main surface modification reaction. Reversed phases containing adamantyl groups attached to the silica surface through ethyl and propyl moieties were prepared in this work. The corresponding olefins, namely 1‐vinyladamantane (adamantyl‐ethene) and 1‐allyladamantane (3‐adamantyl‐propene) are not commercially available, and therefore, they were synthesized prior to the hydrosilation reaction. Infrared and nuclear magnetic resonance (NMR) characterizations of the olefins, and more importantly, those of the resulting bonded phases confirmed success of the reactions. Finally, the chromatographic characterization of the bonded phases, with special emphasis on the separation of basic solutes, was performed. A comparison of the separation performance of the new bonded materials with that obtained from conventional organosilanization is also an important part of the present work. The comparison has been extended to a C₁₈ bonded phase to further emphasize the relationship between solute retention and the chemical nature of the modified silica surfaces.

Keywords:

• HPLC
• Silica hydride
• Silanization

Acknowledgments

The authors wish to thank the National Science Foundation (Grant CHE 9625628, Grant CHE 0094983) and the National Institutes of Health (Grant R15 GM 63519‐01) for partial support of the research reported here. One of the authors (JJP) would like to acknowledge the support of the Camille & Henry Drefus Foundation through the Scholar Program.