Inorganic Chemistry Fluxionality

HideShow resource information
View mindmap
  • 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
    • 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
    • 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

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Inorganic Chemistry resources »