This module will focus on the structure and design of ligands in the development of functional metal complexes.  Three areas will be covered, representing a cross section of pertinent problems in this area, these will be a) the development of catalysts based upon s and f block metals; b) the study of ligand dynamics and their influence on the structure and activity of metal complexes; and c) the stoichiometric and catalytic reactions of p-block elements.  The module will cover the synthesis of targeted ligand precursors, the coordination chemistry of these ligands, and their influence on specific types of reactivity.  Attention will be given to the analysis of structure-activity relationships.

Knowledge

• Show an awareness of the electronic properties of the s, p, d, and f block metals.
• Show an awareness of how ligand structure influences the structure of metal complexes.
• Appreciate the reactivity of metal complexes, and how this can be influenced by changes in the supporting ligands.
• Identify structure-activity relationships in coordination complexes, particularly focussing on ligand structure and coordination geometry vs. reactivity.

Understanding

• Relate the electronic structure of metals to the observed reactivity of metal complexes.
• Understand the properties of ligands, and how design features can be used to control the properties of metal complexes.
• Understand the dynamic nature of many metal complexes, and relate this to observed reactivity patterns.

This module will be delivered in 10 two-hour lectures, supplemented by 4 1-hour class tutorials, and consists of three distinct blocks, each covering a different aspect of advanced ligand design and coordination chemistry. Each block will consist of lectures supported by an assessed piece of coursework.  The three blocks will mirror the three sections described above: (a) the development of catalysts based upon s and f block metals; (b) the study of ligand dynamics and their influence on the structure and activity of metal complexes; and (c) the stoichiometric and catalytic reactions of p-block elements .

Ability to analyse and review the details of ligand design and coordination chemistry, and relate these concepts to physical and chemical properties.

The module will be assessed by a combination of coursework (20%) and written examination (80%). Coursework will be broken down into 3 short, problem-based pieces of work covering each of the three sub-topics.

The applications of ligand design and coordination chemistry to a range of areas, including catalysis and bioinorganic chemistry, with an emphasis on the ability of controlling the properties and reactivity of metal complexes by ligand design.

The properties of d⁰ metals in polymerisation catalysis

A detailed mechanistic understanding of the properties and reactivity of d⁰ metal alkyl and alkyl cations will be discussed.  These complexes have most widely studied in the context of alkene polymerisation, and this type of reactivity will be used to exemplify the reactivity of d⁰ complexes.  The level of detail moves on from that covered in Year 3, encompassing the catalyst structures required for the production of stereospecific polymers.  This area will also cover the use of lanthanides in polymerisation catalysis, as well as the polymerisation of cyclic esters, commonly used as biodegradable polymers.

Heterofunctionalisation catalysis

The role of d⁰ metal complexes as catalysts for a range of organic transformations will be discussed, with particular focus on hydroamination, hydrogenation, hydrosilylation, hydrophosphination, and hydroboration.  A particular focus will be given to looking at the mechanisms of these reactions, for which there are less reaction steps possible (e.g. oxidative addition is precluded).

The applications of alkaline earth metals in catalysis

The quest for reducing the cost and environmental footprint of chemical processes has fuelled the development of catalysts based upon metals other than the Noble Metals (Pt, Ir, Rh, etc.).  The advent of the alkaline earth metals, particularly Mg and Ca, for catalytic processes will be discussed, including their role in hydroamination, hydrosilylation, and hydrogenation catalysis.  The scope and limitations, as well as catalytic reaction mechanisms will be covered.

Introduction to N-Heterocyclic Carbenes (NHC): Structure and Stability

Electronic Structure and Stabilization of N-Heterocyclic Carbenes (Ground-State Carbene Spin Multiplicity, Electronic & Steric Effects, Persistent Triplet Carbenes, Stable Singlet Carbenes)

N-Heterocyclic Carbene transition metal complexes

Synthesis of NHC Precursors

Preparation of Free N-Heterocyclic Carbenes

N-Heterocyclic Carbenes as Ligands

Comparison of Different Types of N-Heterocyclic Carbenes

Carbenes Derived from Four-membered Heterocycles

Carbenes Derived from Five-membered Heterocycles

N-Heterocyclic Carbenes Derived from Six- or Seven-membered Heterocycles

Routes to NHC Complexes

Reactions Catalysed by NHC-Coordinated Metal Complexes

p-Block organometallics

Introduction to p-block organometallics, including structure and reactivity

Introduction to frustrated Lewis pairs (FLPs), and their role in catalysis

Organotransition Metal Chemistry, from Bonding to Catalysis (Hartwig)

The Organometallic Chemistry of the Transition Metals (Crabtree)

Advanced Inorganic Chemistry (Cotton, Wilkinson, Murillo, and Bochmann)

Please see Essential Reading List.