• Presentation
  • Reactions
  • Contact
  • Addition reactions
    • Simple addition
    • Oxidative addition
    • Addition with insertion
    • Addition with elimination
  • Substitution reactions
    • Dissociative mechanism
    • Associative mechanism
    • Exchange mechanism
  • Double sustitution or exchange reactions
    • Halide exchange mechanism
    • Exchange mechanism in other compounds
  • Rearrangement or isomerization reactions
    • Isomerization mechanisms in compounds of representative elements
    • Isomerization mechanisms in coordination compounds
  • Proton transfer reactions
    • Proton transfer in compounds of representative elements
    • Proton transfer in compounds of transition elements
  • Electron transfer reactions
    • Proton transfer in compounds of representative elements
    • Proton transfer in compounds of transition elements

Exchange mechanism in other compounds

Similarly to halides, molecular compounds EXn, where X= OR, NR2, etc., are Lewis acids through E atom and Lewis bases through oxygen atoms nitrogen of the terminal groups, so they can exchange these groups by four centers mechanisms.

Examples

Me3SiOMe + [AlH4]- ⇄ Me3SiH + [AlH3OMe]-

Me3SiOMe + [AlH4]- ⇄ Me3SiH + [AlH3OMe]-

Me3SiOMe + [AlH4]- ⇄ Me3SiH + [AlH3OMe]-

In this reation H- and MeO- are exchanged between silicon and aluminum. The reaction proceeds via an intermediate with alcohóxido and hydride double bridge.

Td E-XA3 + Y ⇄ E-YA3 + X

The reaction intermediate, with a coordination number one unit higher than the starting compound, has the structure of trigonal bipyramid. Both groups, incoming Y and outgoing X groups, are bonded to the central atom. The subsequent dissociation of the leaving group X restores the tetrahedral geometry of the compound.

D4h E-XA3 + Y ⇄ E-YA3 + X

The reaction intermediate, with a coordination number one unit higher than the starting compound, has square planar structure.

Oh E-XA5 + Y ⇄ E-YA5 + X

The reaction intermediate has a coordination number 7, one unit higher than the starting compound. These heptacoordinadas species are fluxional; here we present one of the suggested intermediate geometries for the intermediate reaction.