Dedicated to Professor Harald Schafer on the occasion of his 70th birthdayMolecular metal clusters form a very large and diverse family. They present the opportunity of modeling the intermediates involved in surface mediated catalytic reactions, of providing a source of very reactive mononuclear metal fragments, and of effecting catalytic cycles in which the cluster remains intact. The last mentioned aspect is the subject of this review article. The state-of-the-art of cluster catalysis is critically analyzed. The possibilities offered by molecular metal catalysts of performing catalytic reactions at multimetal atom sites are also discussed.

Choosing the right number and type of elements in modern commercial finite element tools is a challenging task. It requires a broad knowledge about the theory behind or much experience by the user. Benchmark tests are a common method to prove the element performance against analytical solutions. However, these tests often analyze the performance only for single elements. When investigating the complete mesh of an arbitrary structure, the comparison of the element’s performance is quite challenging due to the lack of closed or fully converged solutions. The purpose of this paper is to show a high-precision comparison of eigenfrequencies of a real structure between experimental and numerical results in the context of an element performance check with respect to a converged solution. Additionally, the authors identify the practically relevant accuracy of simulation and experiment. Finally, the influence of accuracy with respect to the number of elements per standing structural bending wave is shown.

The article contains sections titled: 1. Introduction 2. Alkylaluminums and Derivatives 2.1. Physical Properties 2.2. Chemical Properties 2.2.1. Reactions with Olefins 2.2.2. Reactions with Oxygen 2.2.3. Reactions with Metal Compounds 2.2.4. Reactions with Proton‐Donating Materials 2.2.5. Alkylaluminums in Organic Synthesis 2.3. Production of Trialkylaluminums and Alkylaluminum Chlorides 2.3.1. Hydroalumination to Produce Trialkylaluminums 2.3.2. Reaction of Aluminum With Alkyl Halides to Make Alkylaluminum Sesquichlorides 2.3.3. Reduction of Alkylaluminum Sesquichlorides to Make Trialkylaluminums 2.3.4. Reaction of Acids With Trialkylaluminums to Produce Alkylaluminum Chlorides 2.3.5. Reproportionation Reactions 2.3.6. Olefin Elimination and Displacement Reactions 2.3.7. Other Organoaluminum Conversions 2.4. Uses of Alkylaluminum Compounds 2.4.1. Stoichiometric Applications 2.4.2. Catalytic Applications 2.5. Quality Specifications 3. Aluminoxanes 3.1. Production 3.2. Physical and Chemical Properties 3.3. Uses 3.3.1. Mechanism of Polymerization Using Aluminoxanes 3.3.2. Production of Stereoregular Polymers using Aluminoxanes 3.3.3. Polymers Produced by Aluminoxanes 3.4. Analysis and Quality Specifications 4. Handling, Storage, and Transportation 5. Waste Disposal and Environmental Protection 6. Economic Aspects 7. Toxicology and Occupational Health 8. Acknowledgments

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