title: Multifunctional lanthanum tetraphosphonates: flexible, ultramicroporous and proton-conducting hybrid frameworks.
abstract: A new flexible ultramicroporous solid, La(H(5)DTMP)·7H(2)O (1), has been crystallized at room temperature using the tetraphosphonic acid H(8)DTMP, hexamethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid). Its crystal structure, solved by synchrotron powder X-ray diffraction, is characterised by a 3D pillared open-framework containing 1D channels filled with water. Upon dehydration, a new related crystalline phase, La(H(5)DTMP) (2) is formed. Partial rehydration of 2 led to La(H(5)DTMP)·2H(2)O (3). These new phases contain highly corrugated layers showing different degrees of conformational flexibility of the long organic chain. The combination of the structural study and the gas adsorption characterization (N(2) and CO(2)) suggests an ultramicroporous flexible framework. NO isotherms are indicative of a strong irreversible adsorption of NO within the pores. Impedance data indicates that 1 is a proton-conductor with a conductivity of 8 × 10(-3) S cm(-1) at 297 K and 98% of relative humidity, and an activation energy of 0.25 eV.
authors.affiliation: Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos s/n, Málaga, 29071, Spain.
authors.forename: Rosario M P
authors.initials: RM
authors.lastname: Colodrero
authors.forename: Pascual
authors.initials: P
authors.lastname: Olivera-Pastor
authors.forename: Enrique R
authors.initials: ER
authors.lastname: Losilla
authors.forename: Miguel A G
authors.initials: MA
authors.lastname: Aranda
authors.forename: Laura
authors.initials: L
authors.lastname: Leon-Reina
authors.forename: Maria
authors.initials: M
authors.lastname: Papadaki
authors.forename: Alistair C
authors.initials: AC
authors.lastname: McKinlay
authors.forename: Russell E
authors.initials: RE
authors.lastname: Morris
authors.forename: Konstantinos D
authors.initials: KD
authors.lastname: Demadis
authors.forename: Aurelio
authors.initials: A
authors.lastname: Cabeza