Development of Nanoscale Individual Molecular Electric Wire with Highly-efficient Electron Transport Property

一曰：5-10 nm长官能化寡杂环的新合成方法具有与目前通过纳米图案化技术（5- 10 nm间隙）制备的电极间间隙相当的延长的π-共轭长度的低HOMO-LUMO间隙寡聚物的开发已经产生了很大的兴趣。其原因是，这类高度低聚物将成为一个重要的工具，用于提供控制长距离电子隧穿通过一个单一的分子线的参数的具体信息。我开发了一种新的合成方法，以N-甲硅烷基保护的3，4-二氨基噻吩为关键结构单元，合成了一系列精确定义的5- 10 nm长的寡聚噻吩。根据该方法，我已经制备了精确定义的α-14 T（1 - 5 nm）-α-28 T（1 - 10 nm）衍生物，通过制备型凝胶渗透色谱实现了低聚物的纯化，并且通过MALDI-TOF质谱清楚地显示了纯度。所得低聚物的N-甲硅烷基保护的3，4-二氨基噻吩部分的脱甲硅烷基化和进一步化学修饰将提供具有低HOMO-LUMO间隙的各种类型的5- 10 nm长的多官能化低聚物。高分子精确组装的分子积木的设计与合成--集数字/数字化功能于一体的“平面型”分子组装的实现量子计算是材料科学与技术领域的一个巨大挑战。平面型“分子集成电路”的可行途径是i）多功能化大分子的逐步合成和ii）超分子结构的系统组合。沿着这条路线，我一直在开发专门设计的分子模块，用于精确定义的高度低聚物的定向自组装。利用STM方法研究了在超高真空和低温条件下所获得的模块在Au（111）表面的自组装特性。

1 : Novel Synthetic Approach to 5-10 nm Long Functionalized OligoheterocyclesThe development of low HOMO-LUMO gap oligomers with extended π-conjugation length comparable to the inter-electrode gap currently made by nano-patterning techniques(5-10nm gap)has generated a great deal of interest. The reason for this is that highly oligomers of this class will become an important tool for providing specific information on the parameters controlling the long-distance electron-tunneling through a single molecular wire. I have developed a new synthetic approach to a series of precisely defined 5-10nm long oligothiophenes, using N-silyl-protected 3, 4-diaminothiophene as a key building unit. According to this method, I have prepared precisely-defined a-14T(l-5nm) - a-28T(l-10nm)derivatives Purification of the oligomers was achieved by preparative gel permeation chromatography, and the purity was clearly revealed by MALDI-TOF mass spectrometry. The desilylation and further chemical modifications of the N-silyl-protected 3, 4-diaminothiophene moieties of the obtained oligomers will afford various types of 5-10nm long multifunctionalized oligomers with low HOMO-LUMO gap.2 : Design and Synthesis of Molecular Building Blocks for Precisely-defined Macromolecular AssemblyThe realization of "planar-type" molecular assembly integrating the functions required for digital/quantum computing is a great challenge in the field of material science and technology. A feasible approach to the planar-type "Molecular Integrated Circuit" will be the systematic combination of i)the stepwise synthesis of multifunctionalized macromolecules and ii)the supramolecular architecture. Along this line, I have been developing specifically-designed molecular modules for the directed self-assembly of the precisely-defined highly oligomers. The self-assembly properties of the obtained modules on Au(111)surface have been investigated using STM method under UHV and low temperature conditions.