FAST ATOM BOMBARDMENT STUDIES OF AMINO ACID AND PEPTIDE COMPLEXES OF THE URANYL ION - LIGAND ATTACHMENT, DISSOCIATION AND FRAGMENTATION

摘要

Fast atom bombardment in organic matrices of uranyl complexes of several amino acids (AA) and two dipeptides reveals that (i) the coordination sphere can expand in the gas phase to give pentakis species [UO2(AA)(5)](+); (ii) complete stepwise dissociation of ligands AA occurs; (iii) ligand fragmentation takes place via initial loss of non-ligated-NH3+ and CH3 groups, while the carboxy group is retained until the final stage; (iv) clustering of UO2 groups can give such species as [(UO2)(x)(AA)](+); (v) fragmentation of ligated dipeptides occurs mainly via carbon-(amide)nitrogen cleavage, indicating a role of UO22+ in steering molecular breakdown to give amide- or carboxy-containing fragments. [References: 31]