title: The energetics of isomerisation in Keggin-series aluminate cations.
abstract: Electronic-structure calculations show that the ε-isomer of the polyoxoaluminate ion in the Keggin structure [AlO4-(Al(OH)2(H2O))12](7+) is the thermodynamically favoured one. Direct interconversion between the ε- and δ-isomers via cap rotation has a prohibitively high energy barrier in vacuo, suggesting that isomerisation in solution either proceeds via a dissolution-precipitation pathway, or that solvation and/or coordination to counterions reduces the barrier significantly. The implications for the formation of the [Al2O8Al28(OH)56(H2O)26](18+) ion are discussed.
authors.affiliation: School of Chemistry, Monash University, Melbourne, Australia. andy.ohlin@monash.edu.
authors.forename: C
authors.initials: C
authors.lastname: André Ohlin
authors.forename: James R
authors.initials: JR
authors.lastname: Rustad
authors.forename: William H
authors.initials: WH
authors.lastname: Casey