Synthesis and photoluminescence properties of silver(I) complexes based on N-benzoyl-l-glutamic acid and N-donor ligands with different flexibility

Abstract By changing the N -donor ancillary ligand, three novel silver (I) complexes {[Ag(HbzgluO) (4,4′-bipy)]·H 2 O} n ( 1 ), {[Ag 2 (HbzgluO) 2 (bpe) 2 ]·2H 2 O} n ( 2 ) and {[Ag(HbzgluO)(bpp)]·2H 2 O} n ( 3 ) (H 2 bzgluO =  N -benzoyl- l -glutamic acid, 4,4′-bipy = 4,4ˊ-bipyridine, bpe = 1,2-di(4-pyridyl)ethane, bpp = 1,3-di(4-pyridyl)propane) were synthesized. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). In this study, the N -donor ligands are changed from rigidity (4,4′-bipy), quasi-flexibility (bpe) to flexibility (bpp), the structures of complexes also change. Complex 1 features a 1D chain structure which is further linked together to construct a 2D supramolecular structure through hydrogen bonds. Complex 2 is a 1D double-chains configuration which eventually forms a 3D supramolecular network via hydrogen bonding interactions. Whereas, complex 3 exhibits a 2D pleated grid structure which is linked by hydrogen bonding interactions into a 3D supramolecular network. The present observations demonstrate that the modulation of coordination polymers with different structures can accomplish by changing the spacer length of N -donor ligands. In addition, the solid-state circular dichroism (CD) spectra indicated that compound 2 exhibited negative cotton effect which originated from the chiral ligands H 2 bzgluO and the solid-state fluorescence spectra of the three complexes demonstrated the auxiliary ligands have influence on the photoluminescence properties of the complexes.