Introductory description

N/A

Module web page

Module aims

Outline syllabus

This is an indicative module outline only to give an indication of the sort of topics that may be covered. Actual sessions held may differ.

Group theory
Recognition of symmetry elements. Identification of point groups. Elementary uses of character tables such as assigning appropriate symmetry labels to molecular orbitals.
d-d spectroscopy of cubic metal complexes
d-d interelectron repulsion. Microstates and many-electron term symbols for d2. Term symbols for remaining d configurations. Term splittings in cubic symmetry. Qualitative electric-dipole selection rules. Selected examples.
Compound formation: thermodynamic considerations
Stepwise and overall formation constants; extension of concepts developed in CH160
Substitution reations
Classification scheme, A, D, I. Activation parameters and reaction profiles. Solvent exchange rates and relationships to d configurations/spin states/LFSE. Ligand substitution at octahedral complexes – Eigen-Wilkins mechanism and its associated rate law. Ligand substitution at square planar centres. Rate laws. Trans effects and trans influence. Stereospecific synthesis.
Redox reactions
Outer sphere processes and simple Marcus theory. Inner sphere reaction. Diagnostic tests for inner versus outer sphere.
Main group organometallics
Systematic review. Reactivity (source of R- etc). Oxidative addition as applied to Grignard synthesis.
d-Block organometallics – the 18 electron rule
MO diags for octahedral complexes: sigma and pi bonding. Electron counting, co-ordination compounds vs organometallics. Exceptions to the 18 electron rule, including
16 electron square planar complexes.
Bonding of ligands to metal centres.
Carbon monoxide: sigma donation, pi backbonding, effect on IR spectra
Phosphines: bonding and steric effects
Hydrides and dihydrogen: bonding, backbonding and transformation to dihydride. Recognition that is oxidative addition.
Organic molecules as ligands, exemplified through systems such as: 1 bonding with alkyls; 2 with alkenes; 3 with allyls; 4 with cyclobutadiene; 5 with cyclopentadienyl; 6 with benzene
Carbenes: Fischer, Schrock and NHC
Alkanes, agostic hydrogens and noble gases.
Reactions of organometallics
Ligand substitution exemplified by carbonyl replacement, the differences between 16e and 18e complexes (associative vs dissociative substitution). Masked dissociative pathways.
Oxidative Addition and Reductive Elimination.
1,1-Migratory insertion reactions, as exemplified by migration onto carbonyl ligands.
1,2-Insertions and β-hydride elimination. Brief discussion.

Learning outcomes

By the end of the module, students should be able to:

• Use group theory to assign a point group to a molecule and understand the key features of the associated character table.
• Understand why d-d repulsion leads to multiple transitions in electronic spectroscopy.
• Understand the thermodynamics of complex formation and how it leads to an appreciation of the kinetics of ligand substitution (as exemplified by associative, interchange and dissociative processes).
• Understand the difference between inner and outer sphere redox reaction, and how to tell them apart. Use the Marcus cross-relation to approximate reaction rates.
• Understand basic reactivity of TM organometallic complexes, exemplified by ligand substitution, oxidative addition, reductive elimination and migratory insertion reactions.
• Understand and describe the factors affecting reactivity of s and p block alkyls and aryls.Explain successes and limitations of synthetic methods.
• Describe the MO basis for understanding the 18e rule Explain why classical complexes and square-planar organometallics do not follow the 18e rule Count electrons in organometallic complexes.
• Use an MO bonding description to describe the bonding of common ligands to transition metals. Appreciate synthetic methods to make simple complexes.
• Key Skills: Information retrieval, critical analysis, written communication

Indicative reading list

Inorganic Chemistry 6ed by Weller, Overton, Rourke and Armstrong (OUP)

Subject specific skills

Numeracy
Problem solving
Critical thinking

Transferable skills

Numeracy
Problem solving
Critical thinking