Synthetic Manipulation of Main Group Elements with Transition Metal Isocyanides

过渡金属异氰化物对主族元素的合成操作

• 批准号: 2247629
• 负责人: Joshua Figueroa
• 金额: $ 57.5万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247629&HistoricalAwards=false
• 关键词: Synthetic; Manipulation; Main; Group; Elements

With the support of the Chemical Synthesis program in the Division of Chemistry, Professor Joshua S. Figueroa of the University of California, San Diego will study how the chemistry and behavior of main-group elements can be controlled and modulated by transition metal compounds featuring isocyanide supporting groups. The isocyanide supporting groups used in the context of this project provide a protective shield for the chemical interactions between the transition metal and main-group elements. This shield, in turn, allows for the preparation and isolation of molecules that are usually unstable and difficult to obtain. A specific focus of this award is to use iron isocyanide compounds to study and understand the fundamental properties and chemical reactivity of the diatomic molecules boron monofluoride (BF) and diphosphorus. Boron monofluoride, as a free molecule, is not stable under ambient conditions on account of the extreme bonding polarization. Similarly, diphosphorus, unlike its lighter analogue dinitrogen, is also not a stable molecule under normal conditions, preferring instead to condense into polyphosphorus solid materials. With the advent of the m-terphenyl isocyanide supporting groups, stable molecules containing both BF and diphosphorus have been prepared. In the course of this award, detailed investigations into the fundamental nature of BF and diphosphorus will be conducted. These investigations seek to provide answers to basic questions, including 1) how do metal-bound BF and diphosphorus react with other molecules, 2) how do BF and diphosphorus influence the chemical behavior on the metals to which they are bound and, 3) how does the reactivity of metal-bound BF and diphosphorus compare to that of the free, yet unstable, molecules? This project will also focus on the preparation and characterization of other transition-metal-supported main-group element species, with a specific emphasis on generating other unusual or unknown diatomic molecules. The broader impacts activities will include student research training and mentoring, the development of a hands-on laboratory safety course for incoming graduate students, and mentorship of transfer students.This project will specifically focus on the synthesis and reactivity of unusual main-group fragments stabilized by transition-metal m-terphenyl isocyanide complexes. Building on recent reports disclosing the synthesis of an iron terminal boron monofluoride (BF) complex, and a mononuclear diphosphorus complex of iron, detailed investigations will be conducted that aim to elucidate the reactivity of these unusual diatomic ligands with exogenous substrates as well as their specific influence on the transition metal centers to which they are bound. For the terminal BF complex specifically, synthetic studies will be conducted that aim to expand on the pronounced electrophilicity of the boron center, while at the same time detailing reaction profiles that result in the cleavage of the BF unit en route to other metal-boron complexes. In the case of the mononuclear diphosphorus iron complex, its side-on binding mode presents the opportunity to expound upon the fundamental periodic diagonal relationship between phosphorus and carbon. Accordingly, reactivity studies will be conducted that aim to compare and contrast the reactivity of metal-stabilized diphosphorus with that of acetylene and other substituted alkynes. Specific to these efforts will be an assessment of the scope of Diels-Alder-type reactivity between side-on coordinated diphosphorus and organic dienes. In addition, based on preliminary evidence, the electrophilic character of the side-on coordinated diphosphorus with a range of nucleophilic substrates will be evaluated. In parallel to investigations into the nature of BF and diphosphorus coordinated to iron, other low-valent transition metal m-terphenyl isocyanide complexes will be prepared and/or studied with respect to their ability to stabilize unusual main-group fragments, with a focus on the preparation of other unstable or unknown diatomic molecules, especially of the heavier p-block elements. An additional emphasis will be placed on the synthesis of BF complexes of other transition metals in an effort to test electronic structure hypotheses on the factors, electronic environment(s) and conditions that are required to stabilize this reactive diatomic molecule.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学合成项目的支持下，加州大学圣地亚哥分校的Joshua S. Figueroa教授将研究如何通过以异氰化物为特征的过渡金属化合物来控制和调节主族元素的化学和行为支持团体。该项目中使用的异氰化物支持基团为过渡金属和主族元素之间的化学相互作用提供了保护罩。反过来，这种屏蔽可以制备和分离通常不稳定且难以获得的分子。该奖项的一个具体重点是使用异氰化铁化合物来研究和了解双原子分子一氟化硼 (BF) 和二磷的基本性质和化学反应性。由于极端的键合极化，一氟化硼作为游离分子在环境条件下不稳定。同样，二磷与其较轻的类似物二氮不同，在正常条件下也不是稳定的分子，而是更倾向于凝结成多磷固体材料。随着间三联苯异氰化物支持基团的出现，制备了同时含有 BF 和二磷的稳定分子。在该奖项的过程中，将对高炉和二磷的基本性质进行详细研究。这些研究旨在提供基本问题的答案，包括 1) 金属结合的 BF 和二磷如何与其他分子反应，2) BF 和二磷如何影响它们所结合的金属的化学行为，3) 如何金属结合的 BF 和二磷的反应性与游离但不稳定的分子的反应性相比吗？该项目还将重点关注其他过渡金属支持的主族元素种类的制备和表征，特别强调生成其他不寻常或未知的双原子分子。更广泛的影响活动将包括学生研究培训和指导、为即将入学的研究生开发实验室安全实践课程以及对转学生的指导。该项目将特别关注稳定的异常主族片段的合成和反应性由过渡金属间三联苯异氰化物络合物制备。基于最近公开的铁末端一氟化硼（BF）络合物和铁的单核二磷络合物的合成的报告，将进行详细的研究，旨在阐明这些不寻常的双原子配体与外源底物的反应性以及它们的特异性对其所结合的过渡金属中心的影响。特别是对于末端 BF 配合物，将进行合成研究，旨在扩展硼中心的显着亲电子性，同时详细说明导致 BF 单元在通往其他金属硼配合物的途中裂解的反应曲线。就单核二磷铁配合物而言，其侧向结合模式为阐述磷和碳之间的基本周期性对角关系提供了机会。因此，将进行反应性研究，旨在比较和对比金属稳定二磷与乙炔和其他取代炔烃的反应性。具体到这些工作将评估侧配位二磷和有机二烯之间的狄尔斯-阿尔德型反应范围。此外，根据初步证据，将评估侧配位二磷与一系列亲核底物的亲电特性。在研究 BF 和二磷与铁配位的性质的同时，还将制备和/或研究其他低价过渡金属间三联苯异氰化物配合物稳定不寻常主族碎片的能力，重点是其他不稳定或未知双原子分子的制备，尤其是较重的 p 区元素。另外的重点将放在其他过渡金属的 BF 络合物的合成上，以测试稳定这种反应性双原子分子所需的因素、电子环境和条件的电子结构假设。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。