Coordination complexes built with 3-nitrophthalate and different pyrazine derivatives: Syntheses, structures and photoluminescence

Abstract

Three Ag(I) coordination complexes (CCs), namely {Ag2(epyz)(npt)}n (1), {Ag2(tpyz)(npt)}n (2), {Ag2(npt)(NH3)2}n (3), [epyz=2-ethyl-3-methylpyrazine, H2npt=3-nitro-1,2-benzenedicarboxylic acid, tpyz=2,3,5-trimethylpyrazine, mpyz=2,3,5,6-tetramethylpyrazine] have been synthesized by solution phase ultrasonic reactions of Ag2O with H2npt and various pyrazine derivatives ligands under the ammoniacal condition. All the complexes have been characterized by X-ray diffraction, elemental analyses and IR spectra. Complexes 1 and 2 show two-dimensional network. Compound 3 exhibits 1D-chain structure. However, complex 3 shows 3D supramolecular structure results from the linkage of neighboring layers through a rich hydrogen-bonding system involving the ammonia molecules with carboxyl oxygen atoms and the nitro oxygen atoms. Zigzag Ag4 subunits (SBUs) were observed in compounds 1 and 3, while the complex 2 only shows Ag2⋯Ag2 interactions. The structural diversity of the compounds indicated the Ag⋯Ag argentophilicity, the coordination modes of carboxyl groups and the difference pyrazine derivatives play an important role in the formation of such coordination architectures. The thermogravimetric analyses and photoluminescence of the complexes were also investigated.