Khan Anzar, Hecht Stefan
Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
Chemistry. 2006 Jun 14;12(18):4764-74. doi: 10.1002/chem.200501564.
Introduction of photochromic azobenzene units into amphiphilic oligo(meta-phenylene ethynylene)s allowed photocontrol over the helix-coil transition in this important class of foldamers. Two design principles were followed in efforts to accommodate cis- and trans-azobenzene moieties within the helical structure to selectively turn the helical state on and off, respectively. Several oligomer series with varying connectivities to the central azobenzene chromophore were synthesized and these photochromic oligomers were investigated with regard to their folding behavior in both dark and irradiated states. Both the foldamers' chain lengths and the electronic structures of the azobenzene moieties had to be optimized to ensure folding differences and selective excitation of the photochrome. The design of such stimuli-responsive macromolecules, displaying large structural changes upon irradiation, should guide the design of future materials in, for example, "smart" delivery applications.
将光致变色偶氮苯单元引入两亲性聚（间亚苯基乙炔）中，可实现对这类重要折叠体中螺旋 - 线圈转变的光控。为了在螺旋结构中容纳顺式和反式偶氮苯部分，分别选择性地开启和关闭螺旋状态，遵循了两条设计原则。合成了几个与中心偶氮苯发色团具有不同连接性的低聚物系列，并研究了这些光致变色低聚物在黑暗和光照状态下的折叠行为。折叠体的链长和偶氮苯部分的电子结构都必须进行优化，以确保折叠差异和光致变色剂的选择性激发。这种在光照下显示出大结构变化的刺激响应性大分子的设计，应该会指导未来例如“智能”递送应用等材料的设计。
