title: Copper phosphonatoethanesulfonates: temperature dependent in situ energy dispersive X-ray diffraction study and influence of the pH on the crystal structures.
abstract: The system Cu(2+)/H2O3P-C2H4-SO3H/NaOH was investigated using in situ energy dispersive X-ray diffraction (EDXRD) to study the formation and temperature induced phase transformation of previously described copper phosphonosulfonates. Thus, the formation of [Cu2(O3P-C2H4-SO3)(OH)(H2O)]·3H2O (4) at 90 °C is shown to proceed via a previously unknown intermediate [Cu2(O3P-C2H4-SO3)(OH)(H2O)]·4H2O (6), which could be structurally characterized from high resolution powder diffraction data. Increase of the reaction temperature to 150 °C led to a rapid phase transformation to [Cu2(O3P-C2H4-SO3)(OH)(H2O)]·H2O (1), which was also studied by in situ EDXRD. The comparison of the structures of 1, 4, and 6 allowed us to establish a possible reaction mechanism. In addition to the in situ crystallization studies, microwave assisted heating for the synthesis of the copper phosphonosulfonates was employed, which allowed the growth of larger crystals of [NaCu(O3P-C2H4-SO3)(H2O)2] (5) suitable for single crystal X-ray diffraction. Through the combination of force field calculations and Rietveld refinement we were able to determine the crystal structure of [Cu1.5(O3P-C2H4-SO3)] 2H2O (3) and thus structurally characterize all compounds known up to now in this well investigated system. With the additional structural data we are now able to describe the influence of the pH on the structure formation.
authors.affiliation: Institut für Anorganische Chemie, Christian-Albrechts-Universität , Max-Eyth Straße 2, D 24118 Kiel, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Feyand
authors.forename: Annika
authors.initials: A
authors.lastname: Hübner
authors.forename: André
authors.initials: A
authors.lastname: Rothkirch
authors.forename: David S
authors.initials: DS
authors.lastname: Wragg
authors.forename: Norbert
authors.initials: N
authors.lastname: Stock
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D056831:Coordination Complexes; D003300:Copper