Exploiting chirality in mechanically interlocked molecules for new applications in nanotechnology

利用机械互锁分子的手性实现纳米技术的新应用

• 批准号: 2279459
• 金额: --
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2279459
• 关键词: Exploiting; chirality; mechanically; interlocked; molecules

In pioneering publications in Science(1) and J. Am. Chem. Soc.(2) molecular knots have been shown by the Leigh group to have promising catalytic properties due to their well-defined cavities and well-expressed chirality.(1,2) Pentafoil knots, in particular, show very strong affinities for halide anions as a combined result of the multiple hydrogen bond and coulombic interactions that can be utilised for anion binding catalysis.(3) Furthermore, the catalytic activity can be allosterically switched on and off by the addition or removal of metal ions that template the cavity formation in a manner reminiscent of allosteric control in enzymes.(1)This project will aim to prepare a range of molecular knots that contain photoredox-active Ir(III) centres in place of the previously used first row transition metal centres.(1,4 )The iridium centres will play a dual role: Firstly, the relative inertness of Ir(III) allows the isolation of the starting materials as single enantiomers.(5) Due to the required symmetry of the circular helicates, the use of an enantiopure Ir(III) complex should result in the stereoselective synthesis of the knot precursor. Secondly, cyclometallated Ir(III) complexes bearing a bipyridine ancillary ligand are well documented as effective visible light photoredox catalysts.(6)By incorporating photoredox active components into a helicate of single-handedness we aim to achieve stereoselective dual photoredox/anion binding catalysis. As an example, the two step nucleophilic attack of tetrahydroisoquinolines can be promoted by a combined mixture of a photoredox catalyst and an enantioselective hydrogen bond donor catalyst.(7) This process could be achieved in a one pot procedure using Ir(III) knots. We propose controlling the reaction via allosteric interactions using different metal ions as signalling systems. The removal of first row transition metal ions will prevent the system from acting as an anion binding catalyst whilst the photoredox properties will be unaffected. The addition of Fe(II) to template the cavity will allow anion binding but quench the photoredox process. Finally, the addition of Zn(II) should allow both photoredox and anion binding catalysis to work in tandem.This project aims to merge a range of important and emerging areas including molecular knots, photoredox catalysis and switchable catalysis to provide systems capable of catalysing reaction pathways with strict control over both the stereochemistry and regiochemistry in a manner reminiscent of biological systems. Molecular knots are an emerging field with promising potential for switchable catalysis. Chemical topology provides a to date untapped strategy for retaining molecular connectivity whilst altering function. Any progress in using chemical topology to alter reaction pathways would be at the forefront of the field. Whilst the use of photoredox catalysis as a green and mild synthetic method is rapidly on the rise, stereoselective photoredox processes are still in their infancy. Any enantioselectivity achieved using photoredox catalysis would be a significant addition to the current state-of-the-art. Nature is able to finely tune the reaction rate of many complex pathways via allosteric interactions with a wide range of different signalling molecules. The ability to alter synthetic reaction pathways opens the possibility of creating smart systems capable of responding to different stimuli. This project aims to combine a range of emerging technologies to create new and exciting functional catalysts for future applications.1. V. Marcos et. al., Science 2016, 352, 1555-1559.2. G. Gil-Ramirez et. al., J. Am. Chem. Soc. 2016, 138, 13159-13162.3. J.-F. Ayme et. al., J. Am. Chem. Soc. 2015, 137, 9812-9815.4. D. A. Leigh, et. al., Nat. Chem. 2014, 6, 978-982.5. O. Chepelin et. al., J. Am. Chem. Soc. 2012, 134, 19334-19337.6. C. K. Prier et. al., Chem. Rev. 2013, 113, 5322-5363.7. G. Bergonzini et. al., Chem. Sci. 2014, 5,1-60

在科学（1）和J. Am的开创性出版物中。化学（2）Leigh群体已经证明了分子结，由于其定义明确的腔和表达良好的手性，具有有希望的催化特性。（1,2）五方面结，尤其是在哈米尔牛群中非常强的亲和力，表现出非常强的亲和力，作为在多种氢结合和库布尔型相互作用的组合结果，可以使用催化型催化（3），这是催化的催化（3）。通过添加或去除将腔形成模板形成的金属离子以让人联想到酶中的变构控制的方式打开和关闭的变构。（1）该项目的目的是准备一系列包含光电氧基活性IR（III）的分子结，以代替先前使用的第一行过渡金属中心（1 efiim efiim efiim efiim）。 IR（III）允许将起始材料作为单个对映异构体分离。（5）由于圆形螺旋物所需的对称性，使用对映射IR（III）复合物应导致结节前体的立体选择性合成。其次，携带双吡啶辅助配体的环数值IR（III）复合物已充分记录为有效的可见光光毒催化剂。（6）通过将Photoredox活性成分掺入单手的螺旋中，我们旨在实现立体式双光光氧氧和阴离子结合催化催化催化催化性。例如，四氢异喹啉的两个步骤亲核攻击可以通过光氧催化剂的组合混合物和对映选择性氢键供体催化剂的组合混合物。（7）可以在一个盆栽程序中使用IR（III）打孔来实现此过程。我们提出使用不同金属离子作为信号系统的变构相互作用来控制反应。去除第一排过渡金属离子将防止系统充当阴离子结合催化剂，而光毒性特性将不受影响。 Fe（II）的添加为模板，腔将允许阴离子结合，但消除了光氧化过程。最后，添加Zn（II）应允许光电毒素和阴离子结合催化在串联中起作用。该项目的目的是合并一系列重要和新兴领域，包括分子结，光电毒素催化和可切换催化，以提供能够在刻板反应中催化反应路径的系统。分子结是一个新兴领域，具有可切换催化的潜力。化学拓扑提供了迄今为止未开发的策略，用于保留分子连通性，同时改变功能。使用化学拓扑改变反应途径的任何进展都将位于该领域的最前沿。尽管将光毒素催化作为绿色和轻度合成方法的使用迅速上升，但立体选择性光电毒过程仍处于起步阶段。使用PhotoreDox催化获得的任何对映选择性将是当前最新技术的重要补充。大自然能够通过变构相互作用与多种不同的信号分子来细节调整许多复杂途径的反应速率。改变合成反应途径的能力为创建能够响应不同刺激的智能系统的可能性开辟了可能性。该项目旨在结合一系列新兴技术，以为未来的应用创建新的令人兴奋的功能催化剂1。 V. Marcos等。 Al。，Science 2016，352，1555-1559.2。 G. Gil-Ramirez等。 Al。，J。Am。化学Soc。 2016，138，13159-13162.3。 J.-F。 Ayme等。 Al。，J。Am。化学Soc。 2015，137，9812-9815.4。 D. A. Leigh等。 al。，纳特。化学2014，6，978-982.5。 O. Chepelin等。 Al。，J。Am。化学Soc。 2012，134，19334-19337.6。 C. K. Prier等。 al。，化学。 Rev. 2013，113，5322-5363.7。 G. Bergonzini等。 al。，化学。科学。 2014，5,1-60