Diamondoids, synthesis

Schleyer s Lewis acid-catalyzed rearrangement method, which is based on diamondoid thermodynamic stability during carbocation rearrangements, has had little or no success in synthesizing diamondoids beyond triamantane. In recent years, outstanding successes have been achieved in the synthesis of adamantane and other lower molecular weight diamondoids [42 9]. Some new methods have been developed and the yield has been increased to 60%. 

Due to their demanding synthesis, diamondoids are helpful models to study structure-activity relationships in carbocations and radicals, to develop empirical computational methods for hydrocarbons, and to investigate orientational disorders in molecular crystals as well [5,32]. 

Adamantane can be used to construct peptidic scaffolding and synthesis of artificial proteins. It has been introduced into different types of synthetic peptidic macrocycles, which are useful tools in peptide chemistry and stereochemistry studies and have many other applications as well. Introduction of amino acid-functionalized adamantane to the DNA nanostmctures might lead to construction of DNA-adamantane-amino acid nanostmctures with desirable stiffness and integrity. Diamondoids can be employed to constmct molecular rods, cages, and containers and also for utilization in different methods of self-assembly. In fact, through the development of self-assembly approaches and utilization of diamondoids in these processes, it would be possible to design and constmct novel nanostmctures for effective and specific carriers for each dmg. 

By analogy with adamantane, direct, ionic substitution reactions may be expected to be equally as effective for the synthesis of derivatives of other diamondoid hydrocarbons (e.g. diamantane and triamantane). In these cases, however, a larger number of isomers are possible. Diamantane has one methylene and two nonequivalent bridgehead positions while triamantane has four of each. 

W. Bums, T. R. B. Mitchell, M. A. McKervey, J. J. Rooney, G. Ferguson, P. Roberts, Gas-Phase Reactions on Platinum. Synthesis and Crystal Structure of Anti-Tetramantane, a Large Diamondoid Fragment. J. Chem. Soc. Chem. Commun. 1976, 893-895. 

Today nanotechnology includes the synthesis, characterization, and application of a variety of nanostructured materials. Different carbon nanostrucmres exist simultaneously at the nanoscale, including carbon nanotubes, carbon onions, nanodiamond (ND), and diamondoids, all showing unique and novel properties [1]. 

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