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

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), [Ag-2(tpt)(NO3)(PPh3)(2)(H2O)](NO3)center dot 2H(2)O (2), [Ag-8(tpt)(4)(NO3)(4)(mu(2)-CN)(2)](NO3)(2) (3) (PPh3 = triphenylphosphine). Complex 1 crystallizes in a chiral space group P2(1)2(1)2(1), giving a 1D chain and left-handed helical structure which is the first example of metal-tpt complexes with helical chains. Through the pi-pi interactions and C-H center dot center dot center dot 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 center dot center dot center dot O and C-H center dot center dot center dot 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 degrees C, respectively, and both display unusual yellow luminescence in the crystal-state at cryogenic temperature.