New types of blue, red or near IR luminescent phosphonate-decorated lanthanide oxalates

Hydrothermal reactions of the lanthanide chlorides with MeN(CH2CO2H)(CH2PO3H2), (H3L1) (or Me2NCH2PO3H2, H2L2) and sodium oxalate lead to seven new lanthanide oxalate phosphonate hybrids with three types of 3D network structures, namely, [Ln(C2O4){MeNH(CH2CO2)(CH2PO3H)}]0.5 H2O (Ln=Nd: 1; Eu: 2; Gd: 3), [Ln4(C2O4)5(Me2NHCH2PO3)2(H2O)4]2 H2O (Ln=La: 4, Nd: 5), [Ln3(C2O4)4(Me2NHCH2PO3)(H2O)6]6 H2O (Gd: 6, Er: 7). Their structures have been established by X-ray single-crystal diffraction. Complexes 1-3 are isostructural and feature a 3D network formed by the interconnection of 3D network of {Ln(H2L1)}2+ with 1D chains of {Ln(C2O4)}+. Complexes 4 and 5 are isostructural and feature a complex 3D network built from 3D network of lanthanide oxalate and {Ln4(HL2)2} units. The isostructural 6 and 7 form another type of 3D network composed of porous lanthanide-oxalate network inserted by 1D chains of lanthanide-oxalate phosphonate. Compounds 1, 5 and 7 are luminescent materials in the near IR region. Compounds 3 and 6 exhibit a broad blue fluorescent emission band at 451 and 467 nm, respectively. Compound 2 displays very strong and sharp emission bands at 592, 616 and 699 nm with a long luminescent lifetime of 1.13 ms.