Organometallics Flashcards
What is an L-type ligand?
A neutral 2-electron donor
What is an X-type ligand?
An anionic 2-electron donor
What does hapticity (greek symbol eta) mean?
How many atoms in the ligand are interacting with the metal
What does bridging (greek letter mu) mean?
How many metal centres the ligand is bridging
How can we produce transition metal alkyls?
Alkylation of metal halides
Electrophilic attack at a nucleophilic centre
Insertion into a metal hydride bonds
What drives the formation of the alkylation of metal halides?
Salt elimination is the driving force, which compensates for the weak M-C bonds that are formed
What reagent can be used for the alkylation of metal halides?
For example, LiMe (we need a nucleophilic Me group)
What reagent is needed for the synthesis of a TM alkyl from an electrophilic attack at a nucleophilic centre?
We need a strong reducing agent e.g. Na/Hg to break a double metal centre, and then we attack with MeI (something with an electrophilic Me group)
Why can TM complexes undergo agostic interactions?
They have low-lying vacant d-orbitals
What does beta-H elimination form?
A metal hydride and an alkene bonded to the metal
What happens to the electron count and the coordination number when a beta-hydrogen elimination occurs?
The electron count increases by 2
The coordination number increases by 1 (if the alkene occupies the site)
What are the prerequisites for beta-hydrogen elimination?
A vacant site is needed
A beta-H is needed
How can we synthesise a transition metal hydride?
Protonation of a nucleophilic metal centre
Reaction with a hydride source
Oxidation addition
Beta-hydrogen elimination
How can we protonate a nucleophilic metal centre?
A nucleophilic metal centre reacts with HX
What does reacting with Li[HBEt₃] do?
It adds hydride ligands as it is a hydride source
