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具有异氰化物支持基团的过渡金属化合物来控制和调节主族元素的化学和行为。本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。这种屏蔽反过来又使通常不稳定且难以获得的分子得以制备和分离。该奖项的一个特别重点是使用异氰化铁化合物来研究和了解单氟化硼（BF）和二磷双原子分子的基本性质和化学反应性。单氟化硼作为一种自由分子，由于其键的极端极化，在环境条件下不稳定。同样，二磷，不像它的轻类似物二氮，在正常条件下也不是一个稳定的分子，而是倾向于凝结成多磷固体物质。随着间terphenyl异氰酸酯支持基团的出现，制备了既含BF又含二磷的稳定分子。在这个奖项的过程中，将对高炉和二磷的基本性质进行详细的调查。这些研究试图提供基本问题的答案，包括1)金属结合的高炉和二磷如何与其他分子反应，2)高炉和二磷如何影响它们所结合的金属的化学行为，以及3)金属结合的高炉和二磷的反应性与自由但不稳定的分子的反应性相比如何？本项目还将重点关注其他过渡金属支持的主族元素物种的制备和表征，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动手实验室安全课程，以及对转学生的指导。本项目将特别关注过渡金属间terphenyl异氰化物配合物稳定的不寻常主基团片段的合成和反应性。基于最近披露的铁端单氟化硼（BF）配合物和铁的单核二磷配合物的合成报告，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对其结合的过渡金属中心的特定影响。具体来说，对于末端BF配合物，将进行合成研究，旨在扩展硼中心明显的亲电性，同时详细描述导致BF单元在通往其他金属-硼配合物的过程中裂解的反应谱。在单核二磷铁配合物的情况下，它的侧面结合模式提供了阐述磷和碳之间基本周期性对角线关系的机会。因此，将进行反应性研究，目的是比较和对比金属稳定的二磷与乙炔和其他取代炔的反应性。这些工作的具体内容将是评估侧面配位二磷和有机二烯之间diels - alder型反应的范围。此外，基于初步证据，将评价侧对配位二磷与一系列亲核底物的亲电性。在研究BF和与铁配位的二磷的性质的同时，将制备和/或研究其他低价过渡金属间terphenyl异氰化物配合物，以稳定不寻常的主基团片段的能力，重点是制备其他不稳定或未知的双原子分子，特别是较重的p块元素。另一个重点将放在其他过渡金属的BF配合物的合成上，以努力测试对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。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。