abstract
The supramolecular salt [H(2)pip](3)[Ge(hedp)(2)]center dot 14H(2)O (1) H(2)pip(2+) = piperazine cation C(4)H(12)N(2)(2+); hedp(5-) = deprotonated form of etidronic acid, C(2)H(3)P(2)O(7)(5-)) is reported. This consists of an organic inorganic hybrid hydrogen-bonded nanoporous framework, the internal surface of which acts as a template for the three-dimensional (3D) clustering of water molecules. The structure and molecular dynamics of this material are characterised by single-crystal X-ray diffraction, thermogravimetric analysis, Raman (H/D isotopic substitution) spectroscopy, and (2)H solid-state (wide-line and MAS) NMR spectroscopy. Material 1 is shown to be unusual because 1) few nanoporous materials exhibit a well-organised 3D framework of water molecules, 2) it provides a unique opportunity to follow experimentally and to rationalise the deconstruction of a 3D water framework and 3) despite the fact that the hybrid framework is a supramolecular salt, the structure does not collapse after dehydration and the final material is crystalline.
keywords
COORDINATION POLYMERS; (H2O)(10) CLUSTER; CRYSTAL; COMPLEX; ACID; TRANSFORMATION; INCLUSION; HEPTAMER; CHAIN
subject category
Chemistry
authors
Rocha, J; Shi, FN; Paz, FAA; Mafra, L; Sardo, M; Cunha-Silva, L; Chisholm, J; Ribeiro-Claro, P; Trindade, T
our authors
Fa-Nian Shi
Researcher
Filipe Alexandre Almeida Paz
Principal Researcher
João Rocha
Full Professor
Luís Mafra
Principal Researcher
Mariana Coutinho Sardo
Assistant Researcher
Paulo Ribeiro-Claro
Associate Professor with Aggregation
Tito Trindade
Full professorProjects
Nanogotas de Água em Materiais Microporosos e Híbridos Orgânicos-Inorgânicos (PTDC/QUI/65805/2006)
PTNMR - Portuguese Nuclear Magnetic Resonance Network (REDE/1517/RMN/2005)
acknowledgements
We thank the reviewers for their useful comments. We also acknowledge Fundacao para a Ciencia e a Tecnologia (FCT) for funding (PTDC/QUI/65805/2006) and the Fundo Social Europeu. The NMR spectrometers are part of the National NMR Network and were purchased in the framework of the National Programme for Scientific Re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and FCT. Finally, we thank Prof. J. J. Cruz Pinto (Aveiro) for assistance with the TG measurements.