Inorganic Chemistry Fluxionality
- Created by: jfel92
- Created on: 09-01-14 13:56
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- fluxionality
- definition
- transformation in a non-sterochemically rigid moecule that interconverts 2 chemically identical forms of the same molecule
- metal-ligand bond rotation
- rotation about C=C bond
- requires release and recoorination
- high energy
- Propellar-like rotation of M-L bond
- no breakage
- low energy
- Hindered by chelating complexes and bulky substituants
- rotation about C=C bond
- Metal Hopping
- allene with a 90 degree twist, C=C=C
- M 'hops' from one = to the other
- Ring Whizzing
- hapticity 1 bonded, unsaturated HC ligands
- hap 2 or 4 can undergo 1-3 shifts
- M whizzes around ringin series of 1-2 shifts
- result = interconversion of proton types
- all protons end up identical
- 1-3 shifts possible
- hapticity 1 bonded, unsaturated HC ligands
- Bond Mode Interconversion
- same ligand with different hapticity can switch
- slower the ring whizzing, so will occur last
- Pyramidal Inversion
- swaps any 2 groups on a pyramidal centre
- eg. NR3
- makes H environments on Et identical
- 4:6 signal at high temp
- 2:2:6 at low temp
- Berry Twist
- bending of interbond angles of TPB structures
- fluxion over all 5 positions
- too fast for NMR to detectdifferent enironments
- Ligand scrambling
- IR shows terminal and bridging but C13 NMR shows 9 identical environments
- ligand scrambling cuases this
- IR shows terminal and bridging but C13 NMR shows 9 identical environments
- definition
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