PXRD and PDF analysis of multifunctional lanthanide nitrilotris-methylphosphonate-based proton conductors
Pérez-Colodrero, Rosario Mercedes,Cabeza-Díaz, Aurelio,Salcedo, Inés R.,Bazaga-García, Montse,Olivera-Pastor, Pascual
- Published
- 2017-10-01
- Language
- en
Abstract
Metal phosphonates are multifunctional solids which possess tunable properties, such as H-bond networks, while exhibiting high chemical and thermal stability. Depending on the protonation of the ligand, different crystalline phases can be obtained. Here, we report three different families of proton conductors based on lanthanide nitrilotrismethylphosphonates. Compounds having cationic layers compensate by chloride or sulfate anions were isolated: [Ln(H4NMP)(H2O)2]Cl·2H2O and Ln(H5NMP)]·SO4·4H2O [H6NMP = nitrilotris(methylphosphonic acid)]. The crystal structure of Gd-(H5NMP)]·SO4·4H2O was solved ab initio from synchrotron powder diffraction data (λ=0.4124 Å, beamline BL04-MSPD ALBA) and refined by the Rietveld method. Chloride containing phases show two irreversible solid state transformations take place: (1) a crystalline-to-crystalline phase transition, {Ln-H4NMP → [Ln2(H3NMP)2(H2O)4]·4.5H2O for Ln= La, Pr}, and (2) crystalline-to-amorphous phase transition, {LnH4NMP → [Ln(H3NMP)]·1.5H2O for Ln= Gd - Ho}, both implies the loss of HCl and structural rearrangements of the frameworks. Variations in average and local structure have been monitored by high resolution powder diffraction and PDF analysis, upon exposure the samples at high relative humidity and temperature (95% RH and 80 ºC), in order to understand their behavior as proton conductors.
Full text
90 PXRD and PDF analysis of multifunctional lanthanide nitrilotrismethylphosphonate-based proton conductors R.M.P. Colodreroa, A. Cabezaa, I. R. Salcedoa, M. Bazaga-Garcíaa, and P. OliveraPastora. a Departamento de Química Inorgánica, Cristalografía y Mineralogía, Facultad de Ciencias, Campus de Teatinos s/n, Universidad de Málaga, 29071 Málaga (Spain); colodr[email protected] Metal phosphonates are multifunctional solids which possess tunable properties, such as H-bond networks, while exhibiting high chemical and thermal stability1. Depending on the protonation of the ligand, different crystalline phases can be obtained. Here, we report three different families of proton conductors based on lanthanide nitrilotrismethylphosphonates. Compounds having cationic layers compensate by chloride or sulfate anions were isolated: [Ln(H4NMP)(H2O)2]Cl·2H2O2 and Ln(H5NMP)]·SO4·4H2O [H6NMP = nitrilotris(methylphosphonic acid)]. The crystal structure of Gd-(H5NMP)]·SO4·4H2O was solved ab initio from synchrotron powder diffraction data (λ=0.4124 Å, beamline BL04-MSPD ALBA) and refined by the Rietveld method. Chloride containing phases show two irreversible solid state transformations take place: (1) a crystalline-to-crystalline phase transition, {LnH4NMP → [Ln2(H3NMP)2(H2O)4]·4.5H2O for Ln= La, Pr}, and (2) crystalline-to-amorphous phase transition, {LnH4NMP → [Ln(H3NMP)]·1.5H2O for Ln= Gd - Ho}, both implies the loss of HCl and structural rearrangements of the frameworks. Variations in average and local structure have been monitored by high resolution powder diffraction and PDF analysis, upon exposure the samples at high relative humidity and temperature (95% RH and 80 ºC), in order to understand their behavior as proton conductors. Acknowledgements. The work at UMA was funded by MAT2016-77648-R, MAT201341836-R (MINECO, Spain) and FQM-1656 (Junta de Andalucía) research grants and CELLSALBA Synchrotron is thanked for the provision of synchrotron X-ray beamtime at BL04MSPD. 1 P. Ramaswamy, N. E. Wong and G. K. H. Shimizu, Chem. Soc. Rev. 2014, 43, 5913-5932. 2 M. Bazaga-García, G. K. Angeli, K. E. Papathanasiou, I. R. Salcedo, P. Olivera-Pastor, E. R. Losilla, D. Choquesillo-Lazarte, G. B. Hix, A. Cabeza and K. D. Demadis. Inorg. Chem. 2016, 55, 7414–7424. Poster Contributions P-32
