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A series of focally substituted organothiol dendrons of the first through third generation were used to construct adlayers on a gold surface. The presence and structural features of these adlayers were confirmed by X-ray photoelectron spectroscopy, infrared spectroscopy, and ellipsometry. The relative coverage and/or permeability of these adlayers was studied using capacitance and electrochemical blocking experiments. It was found that as the number of hyperbranches in the dendron increased from one to three, the dendron adlayers became initially less and then more permeable. This result indicated a tradeoff between size and packing efficiency when using these molecules to cover a surface. These data also suggest that the dendrons have formed homogeneous but permeable adlayers on the gold surface rather than adlayers consisting of islands of material. These adlayers showed large differences in their ability to trap and hold a small molecule, trans-cyclohexanediol, within them.

The reaction of preformed mixed acetals derived from (α-hydroxyalkyl)dimethylallylsilane with a number of aromatic and aliphatic aldehydes in the presence of Lewis acids results in a highly diastereoselective intramolecular allylation reaction. The reaction proceeds through a cyclic synclinal SE‘ addition of the allylsilane to an intermediate oxocarbenium ion. The reaction occurs exclusively by an intramolecular process as determined by means of a cross-over experiment. The relative stereochemistry was determined by the conversion of one of the allylation products to a known (stereodefined) aldol-type product. A greater degree of diastereoselectivity is obtained by in-situ formation of an oxocarbenium ion from (α-hydroxyhexyl)dimethylallylsilane and an aldehyde in the presence of boron trifluoride etherate. The diastereoselectivity of the in-situ allylation reaction typically exceeds 100:1 in favor of the syn adduct. However, reactions with electron rich aryl aldehydes resulted in a diminished degree of d...

The synthesis of new organothiol-functionalized dendrons of generation 1−4 is described. Several modifications to the original method for preparation of dendrons are detailed that were found to improve the yield and aid in scale-up. A particularly advantageous method for preparation of an aromatic thiol is reported and is employed in this reaction sequence. Several uses of these dendrons are anticipated and briefly described.

As computing elements become smaller and smaller, we must devise ways to encode information in smaller spaces.1 At least as far as strictly spatial encoding is concerned, the two most obvious schemes for nanoscale information storage are (a) continued miniaturization of known microscale elements to approach the nanoscale or (b) tailoring existing nanoscale objects (e.g. molecules) so that they can function as information bearing units (IBUs).