Ternary oxalate-bridged lanthanide complexes from hydrothermal reactions

Four ternary lanthanide compounds: {[Gd2(OX)(BC)2(H2O)4]·2H2O} 1 (OX ¼ oxalate, BC ¼ 1,3-benzenedicarboxylate); {[Ln2 (OX)(NBC)2(H2O)6]·4H2O} (Ln ¼ Eu 2, Gd 3) and {[Tm2(OX)(NBC)2(H2O)4]·2H2O} 4 (NBC ¼ 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 ¼ 13:483ð5Þ; b ¼ 12:814ð4Þ; c ¼ 7:076ð2Þ A ° , b ¼ 104:188ð5Þ8; U ¼ 1185:3ð7Þ A ° 3 for 1, a ¼ 11:211ð4Þ; b ¼ 12:851ð4Þ; c ¼ 9:689ð3Þ A ° , b ¼ 111:726ð5Þ8; U ¼ 1296:8ð2Þ A ° 3 for 4. Compound 2, and 3 are isostructural and crystallize in the triclinic space group P-1 with a ¼ 7:451ð2Þ; b ¼ 9:234ð3Þ; c ¼ 11:585ð3Þ A ° , a ¼ 73:989ð6Þ; b ¼ 71:656ð6Þ; g ¼ 79:707ð6Þ8 U ¼ 723:54ð3Þ A ° 3 for 2, and a ¼ 7:495; b ¼ 9:293ð4Þ; c ¼ 11:649 A ° , a ¼ 73:820; b ¼ 71:618; g ¼ 79:8448; U ¼ 736:0ð11Þ A ° 3 for 3. Thermogravimetric analyses on compound 2, 3 and 4 show their high structural stability as far as to 370 8C. For compound 2, the intensity of the 5D0 –7F2 transition is stronger than that of the 5D0 –7F1 transition. This solid-state luminescent spectroscopy is consistent with the asymmetric construction. q 2004 Elsevier B.V. All rights reserved