This paper in Science reports the synthesis of decamethyldizincocene, a stable compound of Zn(I) with a zinc-zinc bond. In the original LO, the title compound and the starting material, bis(pentamethylcyclopentadienyl)zinc, offer a nice link to metallocene chemistry, electron counting, and different modes of binding of cyclopentadienyl rings as well as more advanced discussions of MO diagrams. More fundamental discussion could focus on the question of what constitutes the evidence for a chemical bond, in this case, the existence of a zinc-zinc bond. In this updated LO, these topics are still covered, however additional topics, such as point group idenitifaction, details regarding the reaction mechanism, electronic structure, and searching the literature using SciFinder are covered. Additionally, electron counting is divided into both the covalent and ionic models.
Students should become more confident reading the primary literature
Students should be able to apply existing knowledge to interpret research results.
Students should be able to apply electron counting formalisms to organometallic compounds.
Students should be able to use 1H NMR spectroscopy data to rationalize structure.
Students can rationalize bond distances based on periodic trends in atomic radii
Students use SciFinder to put this work into a larger context.
Students identify redox reactions based on oxidation changes.
Students identify molecular point groups based upon structures.
Students should be able to connect d electron count to observed colors of compounds.
Students are asked to read the paper and the accompanying Perspectives article before class as well as answer the discussion questions. The questions serve as a useful starting point for class discussion.