CONSTRUCTION OF FUNCTIONAL MOLECULES USING FLEXIBILITY AND ALLOSTERY OF HINGE SUGAR

铰链运动在运动蛋白、信号转导和变构酶的功能中起着至关重要的作用。因此，用小分子模拟这些天然分子机器的铰链区是构建更小分子机器和设备的基础。我们将β-木吡喃糖苷作为潜在的铰链分子，因为这些分子易于经历环翻转，其伴随着所有赤道取代基以钳子样方式转化为轴向取向。同样的环翻转是更困难的相应取代环己烷，因为缺乏异头效应和存在一个额外的轴向氢原子。在我们不断努力从吡喃木糖苷创造分子器件的过程中，我们发明了“铰链糖”，即2，4-二氨基-2，4-二脱氧-β-吡喃木糖苷，它响应于金属离子而将构象从C1转变为1C。在本研究中，我们能够通过形成Pt^<2+>络合物或通过N，N '-羰基化将铰链糖固定在1C构象。有了这个铰链糖，我们还能够构建一个金属离子传感器，1，3-dipyrenylmethyl-hmge糖。二氨基与金属离子的螯合作用导致铰链糖的环翻转，导致双赤道芘基进入双轴取向。平行的芘基团提供受激准分子荧光。这些发现对于未来分子机器和分子器件的构建具有重要意义。

Hinge motions play crucial roles in the functions of motor proteins, signal transducers, and allosteric enzymes. Thus, mimicking the hinge regions of these natural molecular machines with small molecules is the basis for the construction of smaller molecular machines and devices. We brought β-xylopyranosides into focus as potential hinge molecules, because these molecules are prone to undergo a ring-flip, which accompanies the conversion of the all equatorial substituents into axial orientations in a pliers-like manner. The same ring-flip is more difficult with the corresponding substituted-cyclohexanes because of the lack of anomeric effect and the existence of an additional axial hydrogen atom. In our continuing efforts to create molecular devices from xylopyranosides, we invented "hinge sugars," 2,4-diamino-2,4-dideoxy-β-xylopyranosides, which shifts the conformation from C1 to 1C in response to a metal ion. In this stucy, we were able to fix this hinge sugar in 1C conformation by forming a Pt^<2+> complex or by N,N'-carbonylation. With this hinge sugar in hand, we were also able to build a metal ion sensor, 1,3-dipyrenylmethyl-hmge sugar. Chelation of the diamino group to the metal ion causes the ring flip of hinge sugar, leading the diequatorial pyrenyl groups into the diaxial orientations. The parallel pyrene groups afford an excimer fluorescence. These findings are important for the construction of molecular machines and molecular devices in the future.