Institut Parisien de Chimie Moléculaire, Sorbonne Université, CNRS UMR 8232, 4 Place Jussieu, 75005 Paris, France.
Molecules. 2018 Apr 24;23(5):990. doi: 10.3390/molecules23050990.
Molecular tweezers are artificial receptors that have an open cavity generated by two recognition units pre-organized by a spacer. Switchable molecular tweezers, using a stimuli-responsive spacer, are particularly appealing as prototypes of the molecular machines that combine mechanical motion and allosteric recognition properties. In this present study, the synthesis of switchable molecular tweezers composed of a central terpyridine unit substituted in 4,4″ positions by two Pt(II)-salphen complexes is reported. The terpyridine ligand can be reversibly converted upon Zn(II) coordination from a free ‘U’-shaped closed form to a coordinated ‘W’ open form. This new substitution pattern enables a reverse control of the mechanical motion compared to the previously reported 6,6″ substituted terpyridine-based tweezers. Guest binding studies with aromatic guests showed an intercalation of coronene in the cavity created by the Pt-salphen moieties in the closed conformation. The formation of 1:1 host-guest complex was investigated by a combination of NMR studies and DFT calculations.
分子夹是一种人工受体，其具有由两个通过间隔基预组织的识别单元产生的开放腔。可切换的分子夹，使用对刺激响应的间隔基，特别吸引人之处在于它们是结合机械运动和变构识别特性的分子机器的原型。在本研究中，报告了由中心三吡啶单元组成的可切换分子夹的合成，该单元在 4,4″ 位置由两个 Pt(II)-salphen 配合物取代。三吡啶配体可以在 Zn(II)配位时可逆地从自由的“U”形闭合形式转换为配位的“W”开形式。与之前报道的 6,6″取代的基于三吡啶的镊子相比，这种新的取代模式能够实现机械运动的反向控制。与芳香族客体的客体结合研究表明，在闭合构象中，冠醚插入 Pt-salphen 部分形成的腔中。通过 NMR 研究和 DFT 计算的组合研究了 1:1 主客体配合物的形成。
