Different nuclearity silver(I) complexes with novel tetracyano pendant-armed hexaazamacrocyclic ligands

A new series of different nuclearity silver(I) complexes with a variety of tetracyano pendant-armed hexaazamacrocyclic ligands containing pyridine rings (Ln) has been prepared starting from the nitrate and perchlorate Ag(I) salts in acetonitrile solutions. The ligands and complexes were characterized by microanalysis, conductivity measurements, IR, Raman, electronic absorption and emission spectroscopy, and L-SIMS spectrometry. (1)H NMR titrations were employed to investigate silver complexation by ligands L3 and L.(4) The compounds [Ag2L2(NO3)2] (2), ([Ag2L2](ClO4)2.2CH3CN)(infinity) (4), [AgL3](ClO(4)).CH3CN (5), and [Ag4(L4)2(NO3)2](NO3)2.4CH3CN.2H2O (7) were also characterized by single-crystal X-ray diffraction. The complexes have different nuclearities. Complex 2 is dinuclear with an {AgN3O2} core and a significant intermetallic interaction, whereas complex 4 has a polymeric structure formed by dinuclear distorted {AgN4} units joined by nitrile pendant arms. Compound 5 is mononuclear with a distorted {AgN2} linear geometry, and complex 7 consists of discrete units of a tetranuclear array of silver atoms with {AgN3O} and {AgN4} cores in distorted square planar environments. Complexes 2 and 4 were found to be fluorescent in the solid state at room temperature because of the Ag-Ag interactions.