High-Nuclearity Metal Carbonyl Clusters

高核羰基金属团簇

• 批准号: 9729555
• 负责人: Lawrence Dahl
• 金额: $ 39万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2001-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9729555&HistoricalAwards=false
• 关键词: Nuclearity; Metal; Carbonyl; Clusters

Dr. Lawrence F. Dahl of the Department of Chemistry, University of Wisconsin at Madison, is supported by the Inorganic, Bioinorganic, and Organometallic Program of the Chemistry Division to continue his studies on high-nuclearity metal carbonyl clusters. The main thrust of this project is the synthesis, X-ray structural characterization, and structure-bonding analysis of new high-nuclearity (10 or more metal atoms) homo- and hetero-metallic carbonyl clusters. The synthesis of a series of palladium-carbonyl-phosphine clusters will be optimized and extended to include clusters with different phosphine ligands. This series, including a cluster with 59 Pd atoms, will be studied by proton NMR to determine if hydrido-like H atoms are present. New Pd-Ni clusters will be synthesized in sufficient amounts to permit physical/chemical characterization. These clusters will be reacted with phosphine ligands to determine the ligand effect on metal segregation since previous clusters of this type have shown a surprising degree of metal order. A novel carbonyl-phosphine-hydrido cluster with 28 Pd and 12 Pt atoms will be further studied by NMR and hydrogen-deuterium exchange, and synthetically extended by incorporation of additional Pt and Ni atoms. The preparation of a series of Ni-Pd(or Pt)-Rh(or Ir) carbonyl-hydrido clusters with unprecedented metal frameworks will be attempted. The challenging characterization of these unusual clusters will be accomplished by the combination of X-ray crystallography (CCD area detector), electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry, X-ray fluorescence, magnetic susceptibility, and NMR measurements. Theoretical studies on several clusters including a 18-atom Ni-Au cluster will be carried out using density functional methods that include relativistic effects in order to determine the nature of the Ni-Au bonds and to compare the results to those of previous calculations using the Fenske-Hall MO model. Finally, synthetic methods will be improved and optimized to prepare larger amounts of recently discovered 38-metal Au-Pd-Ni and 35-metal Cu-Ni clusters for physical-chemical studies. This project will add fundamental knowledge about bonds between metal atoms, especially ones between different metal types. The large discreet metal clusters also can serve as models for metal particles and surfaces and contribute fundamentally to our understanding of surface science, metal-particle physics, and heterogeneous catalysis. The multi-metal palladium clusters have potential technological importance in the design of new materials with useful catalytic, electronic, magnetic, optical, and hydrogen storage/isotope separation properties. This work also advances state-of-the-art methods of chemical analysis by applying these techniques to extraordinarily demanding problems.

威斯康星大学麦迪逊分校化学系的Lawrence F. Dahl博士在化学部无机、生物无机和有机金属项目的支持下，继续进行高核金属羰基团簇的研究。 该项目的主旨是新型高核（10 个或更多金属原子）同质和异质金属羰基团簇的合成、X 射线结构表征和结构键合分析。 一系列钯-羰基-膦簇的合成将得到优化和扩展，以包括具有不同膦配体的簇。 该系列包括具有 59 个 Pd 原子的簇，将通过质子 NMR 进行研究，以确定是否存在类氢化氢原子。 将合成足够数量的新 Pd-Ni 簇，以进行物理/化学表征。 这些簇将与膦配体反应，以确定配体对金属偏析的影响，因为以前的此类簇已显示出令人惊讶的金属有序度。 将通过核磁共振和氢-氘交换进一步研究具有 28 个 Pd 和 12 个 Pt 原子的新型羰基-膦-氢化簇，并通过掺入额外的 Pt 和 Ni 原子进行合成扩展。 将尝试制备一系列具有前所未有的金属骨架的Ni-Pd（或Pt）-Rh（或Ir）羰基氢团簇。 这些不寻常簇的挑战性表征将通过结合 X 射线晶体学（CCD 面探测器）、电喷雾电离傅里叶变换离子回旋共振质谱、X 射线荧光、磁化率和 NMR 测量来完成。 将使用包含相对论效应的密度泛函方法对包括 18 原子 Ni-Au 团簇在内的多个团簇进行理论研究，以确定 Ni-Au 键的性质，并将结果与​​之前使用Fenske-Hall MO 模型。 最后，合成方法将得到改进和优化，以制备更多最近发现的38金属Au-Pd-Ni和35金属Cu-Ni团簇，用于物理化学研究。 该项目将增加有关金属原子之间的键的基础知识，特别是不同金属类型之间的键。 大型离散金属簇还可以作为金属颗粒和表面的模型，并从根本上有助于我们对表面科学、金属颗粒物理学和多相催化的理解。 多金属钯簇在具有有用的催化、电子、磁性、光学和氢存储/同位素分离特性的新材料的设计中具有潜在的技术重要性。 这项工作还通过将这些技术应用于极其苛刻的问题来推进最先进的化学分析方法。