ON THE STRUCTURE OF LEAD(II) COMPLEXES IN AQUEOUS-SOLUTIONS .1. TRINUCLEAR CLUSTERS

Using semiempirical MNDO method of quantum chemistry the optimal geome tries and corresponding electronic structures of [Pb-3(OH)(n)](6-n) mo del systems as well as of their hydrated [Pb-3(OH)(n)(H2O)(8-n)](6-n) analogues (n = 4, 5) are investigated. The most stable trinuclear lead (II) complexes present in aqueous solutions correspond to cyclo-(mu(3) -OH)(mu(2)-OH)(3)Pb-3(2+), Pb(mu-OH)(2)Pb(mu-OHPb2+, Cyclo-(mu(3)-OH)( 2)(mu(2)-OH)(3)Pb-3(+), Pb(OH)(mu-OH)(2)Pb(mu-OH)Pb(OH)(+) and Pb(OH)( mu-OH)(2)Pb(mu-OHPb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discuss ed.