Synthesis and crystal structure of novel samarium coordination polymer derived from sulfonic acid ligand

The self-assembly of HL (L=[5-(ethoxycarbonyl)-4-phenyl-3,4-dihydropyrimidin-2(1H)-one-6-yl]methanesulfonate) with Sm(ClO4)3·6H2O yielded a 2D coordination polymer {[SmL3(H2O)2]·4H2O}n(1). Its crystallographic data indicated that it belonged to a triclinic system, space group P-1, a=1.42233(8), b=1.47155(8), c=1.53868(9) nm, α=8.62710(10), β=6.35250(10), y=71.5790(10)°, V=2.7241(3) nm3, Z=2, R1=0.0693, wR2=0.1054. X-ray analysis revealed that the local coordination environment around Sm(III) was a slightly distorted dodecahedron in which Sm center was eight-coordinate geometry with eight oxygen atoms from three sulfonic groups, three carbonyl groups and two aqua ligands. Each L− acted as a bidentate spacer to link two Sm centers, resulted in the formation of a 2D hexagonally grid network. The discrete 2D planes in 1 were assembled into a 3D supramolecular network via strong hydrogen bonds among noncoordinated aqua O atoms, coordinated aqua O atoms, and noncoordinated O atoms of sulfonic groups and carbonyl groups. Furthermore, this metal-organic polymer exhibited strong photoluminescence maximized at 379 nm upon 274 nm excitation in the solid state at room temperature.