Hybrid Organic−Inorganic Frameworks (MIL-n). Hydrothermal Synthesis of a Series of Pillared Lanthanide Carboxyethylphosphonates and X-ray Powder ab Initio Structure Determination of MIL-19, Pr[O3P(CH2)2CO2]

• Published in: Inorganic chemistry 1999-10, Vol.38 (21), p.4741-4744
• Main Authors: Serpaggi, F, Férey, G
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic981440i

A series of lanthanide and yttrium carboxyethylphosphonates has been hydrothermally prepared (200 °C, 4 days) from the 1:1 mixture of carboxyethylphosphonic acid and the metal chlorides. The crystal structure of the praesodymium compound PrIII[O3P(CH2)2CO2] has been determined ab initio from X-ray powder diffraction data and refined by the Rietveld method. The compound crystallizes in the monoclinic space group P21/m (No. 11) with cell parameters at 20 °C a = 8.3617(2) Å, b = 7.1899(2) Å, c = 5.4586(2) Å, β = 103.784(2)°, and Z = 2. The final agreement factors converged to the values R p = 0.139, R wp = 0.177, Bragg R = 0.123, R F = 0.055, and χ2 = 3.50. The hybrid framework consists of inorganic Pr/O/P/C layers connected by organic groups, with an interlayer spacing of ∼8.36 Å. The praesodymium atoms are 7-fold coordinated in this pillared layered structure. Isostructural compounds were prepared for yttrium and the entire series of the lanthanide elements.