Ternary oxalate-bridged lanthanide complexes from hydrothermal reactions

Abstract

Four ternary lanthanide compounds: {[Gd 2(OX)(BC) 2(H 2O) 4]·2H 2O} 1 (OX=oxalate, BC=1,3-benzenedicarboxylate); {[Ln 2(OX)(NBC) 2(H 2O) 6]·4H 2O} (Ln=Eu 2, Gd 3) and {[Tm 2(OX)(NBC) 2(H 2O) 4]·2H 2O} 4 (NBC=5-nitro-1,3-benzenedicarboxylate) have been hydrothermally synthesized and structurally characterized. Compound 1 and 4 crystallizes in the monoclinic space group P2(1) c with a=13.483(5), b=12.814(4), c=7.076(2) Å, β=104.188(5)°, U=1185.3(7) Å 3 for 1, a=11.211(4), b=12.851(4), c=9.689(3) Å, β=111.726(5)°, U=1296.8(2) Å 3 for 4. Compound 2, and 3 are isostructural and crystallize in the triclinic space group P-1 with a=7.451(2), b=9.234(3), c=11.585(3) Å, α=73.989(6), β=71.656(6), γ=79.707(6)° U=723.54(3) Å 3 for 2, and a=7.495, b=9.293(4), c=11.649 Å, α=73.820, β=71.618, γ=79.844°, U=736.0(11) Å 3 for 3. Thermogravimetric analyses on compound 2, 3 and 4 show their high structural stability as far as to 370 °C. For compound 2, the intensity of the 5D 0– 7F 2 transition is stronger than that of the 5D 0– 7F 1 transition. This solid-state luminescent spectroscopy is consistent with the asymmetric construction.