Diamondoid Derivatization Chemistry - Towards Nanotechnology Application
S-G Liu, J.E. Dahl and R.M.K. Carlson
MolecularDiamond Technologies, ChevronTexaco Technology Ventures, US
Keywords: diamondoid, diamond, Diamond molecules, nanostructured materials
Diamondoids are diamond molecules which possess the same rigid carbon framework as diamond, making them attractive materials for nanometer-scale construction and other applications. Adamantane (C10H16) is the smallest member consisting of one diamond crystal subunit. Diamantane contains two and triamantane three. Recently we discovered larger members of this class of compounds - higher diamondoids (Science, 2003, 299, 96-99). These include tetramantanes through undecamantane, 1 to 2 nm hydrogen-terminated diamonds containing 4 to 11 face-fused diamond crystal subunits. These molecules encompass a wide variety of 3-dimensional shapes, including rods, helices, and discs, arising from different ways of face-fusing diamond crystal subunits. Structures also include resolvable chiral forms and methylated analogs. Higher diamondoids are extremely difficult to synthesize: only one of the four tetramantanes has ever been synthesized with a multi-step route and a very low yield. Therefore, derivatization chemistry of the higher diamondoids is largely unexplored, but essential for customizing shapes and properties (e.g. mechanical, electronic and biomedical) of these important molecules for various applications. Diamondoid surfaces possess both secondary and tertiary carbons, including primary carbons in the methylated analogs. This offers a wide and selective array of derivatization strategies. In this presentation, for the first time we describe higher diamondoid derivatization reactions, general chemical reactivity, and the effects of symmetry on activation of diamond crystal cages at the surface of higher diamondoids. Advances in the derivatization chemistries for higher diamondoids make possible new applications in a wide range of fields, including pharmaceuticals, microelectronics, and optics, employing polymers, films, and engineered crystals.
Nanotech 2004 Conference Technical Program Abstract