Study On The Coordination Chemistry Of Ag～I Complexes Of Thiazole Dithioether

Five new thiazole dithioether ligands with similar structure and seven Ag^I andone Co^II complexes, obtained by the reactions of these thioether ligands with differentAg^I salts and CoCl₂, have been prepared and characterized. Single-crystal structureanalysis revealed that these Ag^I complexes form diverse structures ranging from 1D to2D networks, while the Co^II complex is mononuclear. The factors that govern theframework formation of Ag^I complexes, including the nature of ligands, counter ionsand solvents, have been discussed. Additionally, other properties, including IR, UVand FL spectra of the ligands and their complexes, have been studied. The majorconclusions are as follows.1) The nature of the ligands plays a crucial role in the construction of thesupramolecular architectures. Firstly, the chain length and the type of the linkerunits affect greatly the coordination modes of the ligands, resulting in diversestructures. Secondly, the steric hinderances around the coordination atoms of theterminal groups influence the coordination modes of the metal ions and theligands, leading to the difference of the final frameworks of the resultantcomplexes.2) The change of the counter ions and the solvents with different coordinationabilities and template effects can influence the available coordination sites of themetal centers and the possible bridging modes between the metal centers and theligands, so that the different supramolecular architectures are formed.3) Both N and S atoms participating in the coordination with the Ag^I centers are onlyfound in two complexes. In other ones, the Ag^I centers are only coordinated withN atoms. The fact indicates that the N atoms of these thioether ligands havestronger coordination ability than the S atoms do.4) Activated by the positive charge because of the thiazolyl N atoms' coordinatingwith the metal ions, the thiazolyl H atoms are prone to the formination of theC–H···O interactions. Additionally, other contacts, such as Ag···O, Ag···S, S···S,S···O or Ag···Ag contacts are also found in most of the Ag^I complexes. These weekinteractions show great influence not only on the molecular arrangement, but alsoon the overall stabilization of the molecular packing.5) The characteristic peaks of the counter ions can be observed only in the IR spectraof the complexes, but no evident difference could be observed in the UV and FLspectra between the ligands and the complexes.