Synthesis Of "Core-shell" Molecular Wires

This thesis is concerned with the studies on the synthesis of "core-shells" molecular wires and their electronic properties, and the synthesis of the aliphatic dendrimers. Additionally, sixteen novel N,N-diacylpiperazine derivatives were synthesized and evaluated as potential antitumor agents. It mainly consists of the following three parts:First, we summarized the importance of the molecular wires in nanotechnology and molecular electronics, and the recent development of the synthesis and measurement of organic molecular wires.In chapter 2, a series of oligo(phenylene ethynylene)s (OPEs) and two oligo(phenylene vinylene)s (OPVs) with different dendrimer side groups have been designed and synthesized. The key steps involved the Sonogashira and Wittig reaction respectively. The molecules contain thiol groups at both ends to enable interconnection between nanoscale gapped metallic electrodes. The different dendrimer groups act as "shells", allowing tailoring to the nanoscopic environment surrounding the OPE or OPV "core". Meanwhile, the dendrimer shells also act as spacers for the precise control of the packing density and intermolecular interaction between the OPE or OPV cores. In addition, novel aliphatic dendrimers were designed and synthesized by shorter synthesis route than that of literature. The key steps involved the addition of Grignard reagents to the suitable esters, dehydroxy group and reduction reaction. These dendrimers can be used to the synthesis of "core-shells" molecular wires with more insulating "shell".In chapter 3, a series of N,N-diacylpiperazine derivatives were prepared and were evaluated for anticancer activity. Most of the compounds showed a moderate degree of anticancer activity for HL-60, BGC-823 and Bel-7402.