Sigma delocalisation via Group 13 Homocatenation

有机聚合物在日常生活中有许多公认的用途。塑料、弹性体、薄膜和纤维用于服装、汽车轮胎、光盘、包装材料和假肢等各种领域。相比之下，由于缺乏合适的合成路线，以无机元素为特征的聚合物的化学通常处于更原始的发展状态。然而，将主族或过渡金属并入聚合物主链中可导致有趣且有用的性质，例如低温柔性、高热稳定性和氧化稳定性以及由不寻常的电子效应（例如σ电子的离域）引起的有趣的电学和光学特性。这项建议旨在建立在我们最近在《科学》杂志上的报告基础上，该报告指出，当第13组中心连接在延伸的线性链中时，会显示出离域的电子特性。类似的性质是目前π共轭的“塑料电子”材料，如聚噻吩和聚乙炔的保护，这是感兴趣的一系列广泛的可能的应用，从太阳能电池和发光器件的分子计算。在我们的目标分子的情况下，电活性是电子沿聚合物单元的σ骨架沿着离域的结果。我们将设计新的路线，以各种聚合物系统的基础上的所有元素的第13族（除铊），并将测试我们的假设，即电子带隙将在很大程度上取决于身份的组成第13族元素的实验和理论。

Organic polymers have many well-established uses in everyday life. Plastics, elastomers, films and fibres are used in areas as diverse as clothing, car tyres, compact discs, packaging materials and prostheses. By contrast the chemistry of polymers featuring inorganic elements is generally at a much more primitive state of development due a paucity of suitable synthetic routes. Nevertheless, incorporation of main group or transition metals into a polymer main chain can lead to interesting and useful properties, such as low temperature flexibility, high thermal and oxidative stability and intriguing electrical and optical characteristics arising from unusual electronic effects such as delocalisation of sigma-electrons. This proposal seeks to build upon our recent report in Science that group 13 centres, when linked in extended linear chains, display delocalised electronic properties. Similar properties are currently the preserve of pi-conjugated 'plastic electronic' materials such as polythiophene and polyacetylene which are of interest in a wide array of possible applications, from solar cells and light emitting devices to molecular computing . In the case of our target molecules the electroactivity is a result of delocalisation of the electrons along the sigma backbone of the polymeric unit. We shall devise new routes to a variety of polymeric systems based upon all the elements of group 13 (excepting thallium) and will test our hypothesis that the electronic band gaps will be largely dependent upon the identity of the constituent group 13 element both experimentally and theoretically.