Unequal coordination environment in complexes of the type [Au2Ag2(R)(4)(L)(2)](n). An immiscible solvent mixture as a key point in the control of ligand replacement

摘要

Following an acid-base strategy, based on the reaction between gold(I) basic fragments and acid silver salts, it is possible to obtain heterometallic polymers of the general formula [Au2Ag2(R)(4)(L)(2)](n) (R = C6Cl2F3; L = pyrimidine). Using this new heterometallic complex [Au2Ag2(C6Cl2F3)(4)(pym)(2)](n) (1) as a starting material, and a good coordinating solvent such as acetonitrile, it is possible to modify the arrangement of the ligands connected to the silver centres and to obtain three different tetranuclear Au2Ag2 building blocks leading to the new polymer [Au6Ag6(C6Cl2F3)(12) (mu(2)-pym)(2)(NCMe)(6)](n) (2). Both complexes display very intense luminescence emission. Structural, experimental and computational studies have been carried out in order to identify the origin of these properties and the factors that can affect them, such as, the presence of metallophilic interactions as well as different coordination environments for the metallic centres.