| Abstract
| - Rigid linear and tripoidal organic modules based on the oligo(phenylene ethynylene) backbonehaving salicylaldehyde-derived termini are synthesized. A highly functionalized 5-iodosalicylaldehyde was prepared and coupled to each ethynyl group of 1,4-diethynylbenzene or 1,3,5-triethynylbenzene in Sonogashira couplings. The two or three termini of the compounds arefunctionalized for incorporation in linear and branched oligonucleotide strands. For the linearmodule (LM), the two termini are equipped with amide spacers, and one of these was functionalizedwith a DMTr (dimethoxytrityl)-protected hydroxy group and the other with a phosphoramidite.One of the tripoidal modules is prepared with DMTr groups in two of its three termini. A tripoidalmodule is also synthesized with three different groups on its hydroxy termini: a phosphoramidite,a DMTr group, and an Fmoc group. Extended studies have shown that these rigid linear andtripoidal organic modules can be incorporated into short oligonucleotides. Several of these modulescan be applied for DNA-directed assembly and covalent coupling into structures of predeterminedconnectivity. Such structures have potential application for molecular electronics and nanotechnology.
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