Theoretical study of AlH(2+)n (n=1-7) dications.

The structures and stability of AlH(2+)n (n = 1-7 )dications were calculated at the ab initio MP2/aug-cc-pVTZ level of theory. The dications AlH(2+) 1 and AIH(2+2) 2 were characterized to be unstable thermodynamically. However, these and the stable dications, AlH(2+)n (n = 3-7) 3-7 have considerable kinetic barriers for deprotonation. Each of the structures 3-7 contains one or more two-electron three-center (2e-3c) bonds. Aluminum atoms of these dications carry most of the positive charges, as indicated by NBO charge calculations.