Synthesis, Reactivity and Catalysis of Novel Metallacarboranes

新型金属碳硼烷的合成、反应性和催化

• 批准号: 0702774
• 负责人: M. Frederick Hawthorne
• 金额: --
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-31 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0702774&HistoricalAwards=false
• 关键词: Synthesis; Reactivity; Catalysis; Novel; Metallacarboranes

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Frederick Hawthorne at the Univesity of Missouri at Rolla to transform redox-dependent molecular conformers (a "nanowagger") into a molecular rotary motor with the potential for powering nanomachines. The driving motion consists of two stable bis-7,8-dicarbollynickel structures having formal Ni(III) and Ni(IV) oxidation states that are interconverted by single-electron redox processes accompanied by a reversible rotational change of the metallocarborane structure from cisoid Ni(IV) to transoid Ni(III) (with respect to cage-C atoms). The proposed research focuses on: (1) A study of the dynamics of substituted dicarbollide ligand rotation about Ni, Fe, and Co centers in diamagnetic commo-bis-7,8-dicarbollide complexes using both 2H and 10B variable temperature NMR measurements. (2) The NMR elucidation of intramolecular interligand interactions resulting from the rotation of substituted motors which brings these substituents into close proximity to one another in the cisoid conformation. (3) Demonstration in solution of reversible intramolecular excimer formation with pyrene substituents caused by redox-controlled rotation of these substituents from the transoid to the cisoid relationship and the reverse (4) Demonstration of controlled motor rotation in solution by the observation of changes in Forster resonance energy transfer (FRET) between two dye molecules each attached to a separate rotor of a motor. (5) Repetition of the FRET experiments described above, but with the motor molecule anchored by a linker group to a sol gel surface. In this way, the operation of surface-mounted motors immersed in liquids, inert gases or vacuum can be demonstrated. The industrial and societal applications of successful nanomotors of this type would enable a new generation of nanomolecular and micro devices. Coupling molecular motors to nanodevices could lead to applications including (1) the control of rotary nanovalves, (2) the control of the philicity of surfaces (hydrophilic / hydrophobic), (3) the control of the color or other optical properties of a surface, (4) the throttling of the activity of catalytic sites, (5) the mechanical transference of optical activity between chiral centers and switches for the chemical or electrochemical control of electrons and photons. Since research in this area involves molecular design, computational studies, syntheses, spectroscopy of all types, X-ray diffraction molecular structure studies, electrochemistry and nanodevice construction, students at all levels will receive broad experience for continued research in academia, government or industry.

无机，生物无机和有机化学计划的这一奖项支持了密苏里州大学的弗雷德里克霍桑教授在罗拉的研究，将氧化还原依赖的分子构象（一种“聚合物”）转化为具有为纳米机器提供动力的潜力的分子旋转马达。 驱动运动由两个稳定的bis-7，8-dicarbollynickel结构具有正式的Ni（III）和Ni（IV）的氧化态，是相互转换的单电子氧化还原过程伴随着可逆的旋转变化的cisoid镍（IV）transoid镍（III）（相对于笼-C原子）的cisarborane结构。 （1）利用2 H和10 B变温核磁共振技术研究了抗磁性commo-bis-7，8-dicarbolide配合物中取代二卡宾配体绕Ni、Fe和Co中心转动的动力学。(2)NMR阐明了分子内配体间的相互作用，这是由于取代的马达的旋转使这些取代基在顺式构象中彼此非常接近。(3)在溶液中，通过氧化还原控制这些取代基从transoid到cisoid的旋转关系和相反的关系，证明了具有芘取代基的可逆的分子内激基缔合物形成。（4）通过观察两个染料分子之间的福斯特共振能量转移（FRET）的变化，证明了溶液中受控的马达旋转，每个染料分子都连接到马达的单独转子上。(5)重复上述FRET实验，但马达分子通过连接基团锚定到溶胶凝胶表面。通过这种方式，可以演示浸入液体、惰性气体或真空中的表面安装电机的操作。这种成功的纳米马达的工业和社会应用将使新一代的纳米分子和微型器件成为可能。 将分子马达耦合到纳米器件可以导致包括以下应用：（1）控制旋转纳米阀，（2）控制表面的亲合力（亲水/疏水），（3）控制表面的颜色或其它光学性质，（4）抑制催化位点的活性，（5）手性中心和开关之间光学活性的机械转移，用于电子和光子的化学或电化学控制。 由于该领域的研究涉及分子设计、计算研究、合成、所有类型的光谱学、X射线衍射分子结构研究、电化学和纳米器件构建，因此各级学生将获得在学术界、政府或行业继续研究的广泛经验。