A study on oxygen insertion in dinuclear silver cryptates

Two novel silver(I) cryptates are reported in this paper. Ag(2)(L(1)O)](ClO(4))(2).H(2)O and Ag(2)L(1)](ClO(4))(2).1.5H(2)O were synthesized by the condensation of tris (3-aminopropyl) amine with m-phthalaldehyde in the presence of silver(i) ion, under aerobic and anaerobic conditions, respectively. (The ligand L(1)O represents the oxygen insertion product of L(1).) Cryptates 1, 2 and their hydrogenated ligand H(12)(L(1)O) 3 and H(12)L(1) 4 (obtained by reduction of the cryptates) were investigated by electrospray mass spectroscopy (ES-MS). 1 and 2 were also decomposed by HCl treatment and their products were separated and identified by HPLC and ES-MS. Our experiments show that cryptate 2 is able to activate dioxygen that results in quantitative aliphatic hydroxylation of L(1) on one of its HC=N bonds. Crystal structure analysis shows an interesting difference between 1 and 2 in that 1 is an oxygenated and 2 is a non-oxygenated cryptate. Up to date, ligand hydroxylation has not been achieved in silver(I) complex-O(2) systems.