Complex Hydrothermal Reaction Systems: A Systematic Investigation of Copper Phosphonatoethanesulfonates by High-Throughput Methods

The polyfunctional. ligand 2-phosphonoethanesulfonic acid, H2O3P-C2H2-SO3H (H3L), was used in a high-throughput (HT) investigation of a new class of compounds, the copper phosphonatosulfonates. An extensive HT study comprising 288 individual hydrothermal reactions was performed to systematically investigate the influence of temperature, pH, and molar ratio of Cu2+/H3L in the reaction system Cu(NO3)(2)/H3L/NaOH/H2O/temperature, The HT investigation led to five new compounds CU2[(O3P-C2H4-SO3)(OH)(H2O)](H2O) (1), Cu(2.5)3(O3P-C2H4-SO3)(OH)(2) (2), Cu-1.5[(O3P-C2H4-SO3)(H2O)]center dot H2O (3), Cu-2[(O3P-C2H4-SO3)(OH)(H2O)(2)]center dot 3H(2)O (4), and NaCu(O3P-C2H4-SO3)(H2O)(3) (5). Their fields of formation were established unequivocally and from the large amount of data reaction trends were extracted. Furthermore, a new compound CU1.5(O3P-C2H4-SO3)(H2O) (6) was synthesized under hydrothermal reaction conditions in a glass reactor. For compounds 1, 2, and 6 crystal structures were determined by single-crystal X-ray diffraction. The compounds exhibit a large structural variety. Thus, CUO4, CuO5, and CuO6 units are observed. Corner-, edge- as well as face-sharing polyhedra form chains, layers, or Cu3O12 clusters that are connected by the -CH2CH2- group of the ligand. Thermo-gravimetric investigations, magnetic measurements, IR spectra as well as chemical analyses of compounds 1, 3, 4, 5, and 6 are also presented. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)