Synthesis and structural determination of polynuclear nine-coordinate {K[SmIII(Egta)] • H2O} n and mononuclear eight-coordinate (NH4)[LuIII(Egta)] • H2O

Abstract

Two novel rare earth metal coordination compounds, {K[SmIII(Egta)] · H2O} n (I) (H4Egta = ethyleneglycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid) and (NH4)[LuIII(Egta)] · H2O (II), have been successfully synthesized through direct heating reflux and characterized by FT-IR spectroscopy, thermal analysis and single-crystal X-ray diffraction techniques (NIF file CCDC nos. 966211 (I) and 966210 (II)). Complex I shaps a polynuclear and nine-coordinate structure with distorted monocapped square antiprismatic (MC-SAP) conformation and crystallizes in the monoclinic crystal system with space group C2/c. The central Sm3+ ion is coordinated by two nitrogens and six oxygens from one octadentate Egta ligand. Meanwhile, one oxygen atom comes from one carboxylic group of the neighboring Egta ligand, forming one dimensional unlimited polynuclear complexes. The cell dimensions are: a = 38.253(3), b = 13.7769(11), c = 8.7652(7) A, β = 100.696(2)° and V = 4539.0(6) A3. Complex (II) adopts a mononuclear structure with eight-coordinate pseudo-SAP conformation and crystallizes in the monoclinic crystal system with space group P21/c. The central Lu3+ ion is coordinated by two nitrogens and six oxygens all from one octadentate Egta ligand. The crystal data are as follows: a = 13.9817(10), b = 9.7392(6), c = 14.6305(13) A, β = 110.267(9)° and V = 1868.9(2) A3.