Organometallic Chemistry

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Organometallic compounds are, probably unsurprisingly to you, most strictly defined as any complex in which there is a bond between a carbon atom (or functionality) and a metal atom. This isn’t the only definition, and you may want to look up some of the others, but holds true for what we’ll work with in this resource. Given the multitude of different metals in the periodic table and the variety of different functional groups that carbon is found in, you can probably imagine how many of different types of organometallic complexes exist (Figure 1 in the attached Figures.pdf resource.)

With this breadth, these species can exhibit a very wide range of behaviours, have found applications in many different areas, and have won lots of Nobel prizes [1]. Given this scope, this resource will be limited to only organo-transition metal chemistry, but if you’re interested, there’s a huge amount more out there (use a well-known online encyclopaedia - that your teacher probably hates - to look up ‘uranocene’, as just one example).

The first true transition-metal organometallic to be synthesised was Zeise’s salt (Figure 2 in the attached Figures.pdf resource), prepared in Copenhagen in 1830 by William Christopher Zeise [2]. This compound is an adduct of platinum and ethene, where the organic component is bound to the metal centre via a dative bond from its π-system. Despite this compound not being very useful for anything, it is of great importance as it very much kicked off research into organometallics and posed key questions into the nature of the bonding in these compounds.

Since this discovery, thousands and thousands of organometallic complexes have been made. One particular area where these species have been very heavily exploited is in catalysis (see the resource on ‘Catalysis’ in this series) both on massive industrial scales (synthesis of medicines, processing of oil, production of materials e.g. polymers, etc.) and on small academic scales (the development of new reactions and processes to address the changing needs of society). Furthermore, they’ve been discovered to be of great importance in biology - vitamin B12 (cobalamin) and its active derivative forms, found in breakfast cereals (check the box), are a set of organo-cobalt compounds [3]. I would draw one, but they’re big. Look one up, I particularly like adenosylcobalamin.

Use a search engine to find as many different places and applications where organometallic complexes are used as you can.

Presumed Knowledge

Just a few quick things you might want to make sure you’re familiar with/dimly recall before jumping straight into this work-sheet:

• The octet rule.
• The use of ‘skeletal’ formulae to represent molecules.
• How the electronic configurations of elements are described (sˆx pˆy dˆz, etc.)
• That there’s a spectrum of bonding between purely ionic and purely covalent interactions.
• Some understanding of how covalent bonding arises from the interactions between the individual atomic orbitals of a molecule.