ELECTRONIC AND GEOMETRIC ORIGINS OF THE NON-INNOCENT NATURE OF LIGANDS

配体非无辜性质的电子和几何起源

• 批准号: 7954461
• 负责人: Robert Karoly Szilagyi
• 金额: $ 0.19万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7954461
• 关键词: Behavior; Binding Sites; Catalysis; Chemicals; Computer Retrieval of Information on Scientific Projects Database; Data; Electronics; Funding; Grant; Guidelines; Institution; Investigation; Ions; Ligands; Measurement; Metals; Molecular; Mono-S; Nature; Nitrogen; Organometallic Chemistry; Oxidation-Reduction; Oxygen; Phosphorus; Research; Research Personnel; Resources; Series; Source; Sulfur; Support System; System; Transition Elements; Translating; United States National Institutes of Health; absorption; base; scaffold; structural biology; synchrotron radiation

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We propose multi-edge x-ray absorption studies to dissect the fundamental molecular details of the non-innocent behavior of ligands in coordination compounds. The non-innocent nature of ligands is best characterized macroscopically by ligand-based reactivity, where the central metal becomes a spectator and most often a steric scaffold rather than a reactive site. Microscopically this translates into valence orbitals that are rich in ligand contribution (i.e. large ligand covalency). We have already collected preliminary data for formally Ni(II)/Ni(III) redox couple system supported with a pincer-type ligand denoted PNP (PNP = N[2-P(CHMe2)2-4-methylphenyl]2) at the Ni L-, Cl and P K-edges that clearly demonstrate the feasibility of our measurements. Our data unexpectedly show the non-innocent behavior of the pincer-type ligand PNP originally thought to be innocent ancillary in the context of organometallic chemistry and catalysis. Previously this behavior was mainly observed for sulfur and oxygen containing ligands, such as dithiolenes and catecholes. We first plan to study two pincer-type ligands with PCP and PNP compositions that are coordinated to a series of first row transition metals as central metals in their formally mono-, di-, and trivalent forms. Given the reducing ability of phosphorus, we will also investigate pincer ligands having only nitrogen donors, specifically the monoanionic NCN system C6H3[1,3-CH2NiPr2]2. These proposed investigations are part of a larger project aiming to understand the physical-chemical factors that can contribute to non-innocent behavior as a function of the 3d transition metal ion (when shifting from late to mid) and the nature of the heteroatom in the ligand. We wish to set up guidelines for synthetic chemists to be able a priori predict non-innocent behavior.

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