This literature discussion is based on a paper describing the ligand-based reductive elimination of a diphosphine from a thorium compound (Organometallics, 2017, ASAP). The thorium compound contains two bidentate NHC ligands providing an opportunity to discuss the coordination of these ligands. The ligand-based reduction is very subtle and would be challenging for students to pick up without some guidance. The compound undergoing reductive elimination also presents an excellent introduction into magnetic nonequivalence and virtual coupling.

This problem set was designed to be an in-class activity for students to practice applying their knowledge of metal-metal bonding (as discussed in the previous lecture) to recently published complexes in the literature. In this activity, complexes from four papers by Christine M. Thomas and coworkers are examined to give students practice in electron counting (CBC method), drawing molecular orbitals, and fundamental organometallic reactions.

Literature discussion about the first examples of molecular hydrogen complexes isolated by Gregory J. Kubas in the early 80s. The questions are divided into groups with two levels of difficulty.

The more basic group of questions includes topics on:

1)      Coordination Chemistry: electron count, geometry, oxidation state, orbital interactions, types of ligands, binding modes, cis/trans and fac/mer isomers.

2)      Symmetry elements and point groups.

3)      Basic concepts on spectroscopy: NMR, Raman, IR, UV/Vis, XANES, EXAFS, neutron and X-ray diffraction

In this literature discussion, students read an Inorganic Chemistry paper (doi: 10.1021/ic503062w) about diarylamido-based PNZ pincer ligands and their Ni, Pd, and Rh complexes. Specifically, this paper uses IR and E_1/2 potentials to demonstrate that the redox events occur not on the metal center but on the pincer ligands.