Thermally stable helical chain and octanuclear Ag(I) coordination networks with yellow luminescence

Abstract

The reactions of 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tpt) and Ag(I) ions under solvothermal or solvent evaporation conditions yielded three new coordination complexes with the interesting frameworks: [Ag(tpt)(NO3)]n (1), [Ag2(tpt)(NO3)(PPh3)2(H2O)](NO3)·2H2O (2), [Ag8(tpt)4(NO3)4(µ2-CN)2](NO3)2 (3) (PPh3= triphenylphosphine). Complex 1 crystallizes in a chiral space groupP212121, giving a 1D chain and left-handed helical structure which is the first example of metal-tpt complexes with helical chains. Through the π–π interactions and C–H⋯O hydrogen bonding, the 1D chains of 1 further form a 3D supramolecular structure. Dinuclear complex 2 gives a 3D network via intramolecular O–H⋯O and C–H⋯O hydrogen bonding, while the octanuclear complex 3 affords a 2D framework through weak Ag⋯Ag interactions and van der Waals force. Complexes 1 and 3 exhibit high thermal stabilities at 350 and 300 °C, respectively, and both display unusual yellow luminescence in the crystal-state at cryogenic temperature.