Inter- and intra-molecular pathways in polyamine synthesis from diamines†
Characterisation, largely through crystal structure determinations of their metal complexes, of the polyamine products of several reactions between (in all but one case) polyalcohol benzenesulfonates and 1,2- and 1,3-diamines, confirmed that intramolecular reaction pathways are important only in the 1,2-diamine reactions. Even under conditions where the amine reactants are in large excess, however, it is possible to obtain products resulting from alkylation of a diamine by more than one molecule of sulfonate (or, in one case, of a bromochloroalkane). In metal ion complexes formed by the new ligands there are examples of only partial coordination of the N-donor sites, giving species which might be suitable for further, selective functionalisation at the unbound centres. Conversion of the complexes into macrocyclic derivatives also suited to further functionalisation is straightforward.