This 5 slides about will introduce students to the concept of photoinduced electron transfer. These slides go over the energics of photoinduced electron transfer, which implements basic concepts of photochemistry and electrochemistry. The photoinduced electron transer properties of ris-(2,2'-bipyridine)-ruthenium(II) is used as an example.
In this literature discussion, students read a paper about a cobalt metallopeptide that imitates the active site of the enzyme nitrile hydratase. Specifically, the model complex is oxidized by air to produce a coordination sphere with both cysteine thiolate and sulfinic acid ligands, much like the post-translationally oxidized cysteine ligands in the biological system.
This is an in-class PDB exercise based on the paper "Mechanisms Controlling the Cellular Metal Economy" by Gilston and O'Halloran. Students are asked to visualize the metal binding sites of several proteins discussed in the paper, highlighting unusual metal geometries. After identifying the amino acid residues involved in metal binding, students will discuss the bond structure in terms of HSAB theory.
This five slides about chemical exchange transfer (CEST) discusses the magnetic properties of paramagnetic metal ions and their use as MR imaging agents. This includes tranditional contrast agents that affect the relaxation rate of nearby water protons and paramagnetic shift reagents suitable for CEST imaging applications. A recent redox-active cobalt complex is presented as an innovative agent for mapping redox imbalances in vivo.
This is a literature discussion of a review by Tom O'Halloran (The link to the paper is included in the "Web Resources" below). The review covers concepts of metal content in cells, metal trasport, storage, and regulation. Its a good review to start a broader or deeper discussion about metals in biology. We have provided some questions to help guide the student discussion. These questions can be given to students prior to coming to class, and the answers can either be used for the in-class discussion and/or collected.
In this experiment, students will synthesize a cobalt Schiff base complex with varying axial ligands ([Co(acacen)L2]+). They will characterize the complex using various techniques, and may perform computational modeling to predict spectroscopic properties.
This is a literature discussion based on the paper “Spectroscopic Elucidation of the Inhibitory Mechanism of Cys2
This activity is designed to give students a deeper understanding of what post-translational modification does in a metalloenzyme using nitrile hydratase (NHase) as a model system. The metallo-active site of NHase contains a cobalt(III) center that is bound to an unusual coodination sphere containing bis-amidate, cysteinate, sulfenate (RSO-), and sulfinate (RSO2-) ligands.
Students are asked to read an article detailing the development of a cobalt-based MRI contrast agent ("A Redox-Activated MRI Contrast Agent that Switches Between Paramagnetic and Diamagnetic States", Tsitovich, P. B.; Spernyak, J. A.; Morrow, J. R. Angew. Chem. Int. Ed. 2013, 52, 14247-14250, DOI: 10.1002/anie.201306394). Before coming to class the students are asked to answer a series of questions designed to guide them through the first half of the article, and to be prepared to discuss their answers in class.
The students will write a paper in which they analyze the Vitamin B12 co-enzyme from biological, chemical and biochemical perspectives, and will use the guided questions to help show the relevance of an organometallic chemistry experiment to real biochemical systems. This activity is based on a synthetic lab experiment that students would have performed on transition metal-carbon bonds in biology and chemistry (The lab experiment was adapted from third edition of “Inorganic Experiments” by Derek Woollins).