Facile synthesis of two new hexa-/octa-nuclear silver clusters and investigation of their optical features

Abstract Two new silver clusters, [Ag6(PhC≡C)2(bpy)4(NO3)4] (1), bpy=2,2'-bipyridine, Ag8(Phen)4(NEA)8(CH3CN)2 (2), NEA = naphthalene acetic acid, were synthesized with assistance of ultrasonic irradiation and their unique structure investigated by single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction analysis (PXRD) and Ultraviolet-visible spectrum (UV-Vis). Thermal stability of the clusters were studied through thermogravimetric analysis (TGA).The photoluminescence analysis of 2 was also carried out. Clusters 1 and 2 show the absorption bands at λmax in the range 200-380 nm and 310 nm, respectively. The band gap widths for clusters are 3.05 eV and 3.20 eV. The Ag…Ag contact range in the cluster 1 is 2.7211(4) A–3.1102(3) A and for the cluster 2 is 2.867–3.047 A.