In this paper by Andersen and Berg (J. Am. Chem. Soc., 1988, 110 (14), pp 4849–4850) the authors present magnetic measurements that refute the calculated ground state of an organometallic cobalt nitrosyl dimer. Students will learn about two physical techniques for measuring magnetism and will learn how magnetic measurements can be used to indicate paramagnetism versus diamagnetism.
This is a literature-based activity that focuses on a review I recently published as part of a thematic series on C-H activation.
The review highlights similarities between the newly discovered frustrated Lewis pairs and polarized metal-ligand multiple bonds. There are many ways to use the review, but the attached set of questions focuses on drawing analogies among seemingly diverse types of reactivity using frontier-molecular-orbital considerations.
This is the In Class Activity that I use to review the concepts of Lewis Dot Structures, LDS, (connectivity, resonance, formal charges, etc.) learned in General Chemistry and to introduce new ideas of resonance contributions to the character of the molecule. The question itself is apparently very simple, but the discussion that it produces can be quite rich and brings in both new and old ideas of LDS, providing both a good review and a good segue into advanced ideas of Lewis Dot Structures.
This contains three parts: A "Pre-Read" section for students to read before coming to class, an in-class worksheet to be worked in groups, and instructor keys for the worksheet.
The purpose of this exercise is to familiarize and give practice with identifying major classes of reaction (oxidative addition, etc.) in an organometallic catalytic cycle. After this exercise, students should be able to do the same for a new catalytic cycle provided by the instructor on a homework set or exam.
This is a literature discussion based on an interesting Bergman/Arnold paper utilizing d2 niobium imido complexes for the semihydrogenation of arylalkynes to Z-alkenes. The mechanism is quite unusual, and I found it to be an interesting paper to discuss after we had talked about the classical hydrogenation mechanisms (typically observed for late transition metals). The students should come into the discussion understanding fundamental reaction mechanisms (including σ-bond metathesis), and it's helpful if they are somewhat familiar with mono- and dihydride mech
This in-class activity and the related problem set allows students to discover the linear and bent bonding modes of NO to metals based on VSEPR theory through guided inquiry. Two examples follow which illustrate how the electrons are counted in NO complexes depending on the coordination mode/formal charge of NO. Students must have had prior practice in counting electrons of complexes to complete the problems.
Determining the reactive intermediates in metalloenzymes is a very involved task, and requires drawing from many different spectroscopies and physical methods. The facile activation and oxidation of methane to produce methanol is one of the "holy grails" of inorganic chemistry. Strategies exist within materials science and organometallic chemistry to activate methane, but using the enzyme methane monooxygenase, nature is able to carry out this difficult reaction at ambient temperatures and pressures (and in water, too!).
This lecture provides a short introduction to the other half of biological iron chemistry: enzymes that do not contain a porphyrin group that ligates the iron atom. There are several important applications for non-heme iron in cells, both mammalian and bacterial. Oxygen activating non-heme iron enzymes fall into a few basic categories and includes mononuclear iron monooxygenases and dioxygenases, and binuclear iron monooxygenases. The requirements to activate and utilize dioxygen will be given.
These slides provide a brief introduction to the concept of electrocatalysis using the glyoximato cobalt catalysts for hydrogen production recently examined by Peters, Gray, and others. They provide a suitable introduction to the topic for students interested in reading the primary literature on these topics.