title: The construction of open Gd(III) metal-organic frameworks based on methanetriacetic acid: new objects with an old ligand.
abstract: The preparation, X-ray crystallography and magnetic investigation of the first examples of methanetriacetate (mta)-containing lanthanide(III) complexes of formulae [Gd(mta)(H(2)O)(3)](n)4 n H(2)O (1) [Gd(mta)(H(2)O)(3)](n)2 n H(2)O (2) and [Gd(2)(mta)(2)(H(2)O)(2)](n)2 n H(2)O (3) are described herein. This tripodal ligand promotes the formation of 6(3) networks; thus 1 consists of a honeycomb structure, whereas in 2 two of these layers are condensed to form a rare five-connected two-dimensional (4(8)6(2)) network. Compound 3 can be seen as an aggregation of 6(3) layers leading to a three-dimensional (6,6)-connected binodal (4(12)6(3))(4(9)6(6))-nia net, in which the gadolinium(III) ions and the mta ligands act as octahedral and as trigonal prismatic nodes, respectively. The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. A close fit to the Curie law (1) and weak either antiferro- [J=-0.0063(1) cm(-1) (2)] or ferromagnetic [J=+0.0264(6) cm(-1) (3)] interactions between the Gd(III) ions are observed; the different exchange pathways involved [extended tris-bidentate mta (1) and mu-O(1);kappa(2)O(1),O(2) (2 and 3) plus single syn-syn carboxylate-mta (3)] accounting for these magnetic features. The nature and magnitude of the magnetic interactions, between the Gd(III) ions in 1-3, agree with the small amount of data existing in the literature for these kind of bridges.
authors.affiliation: Laboratorio de Rayos X y Materiales Moleculares, Departamento de Física Fundamental II, Facultad de Física, Universidad de La Laguna, Avda, Astrofísica Francisco Sánchez s/n, 38204 La Laguna, Tenerife, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Cañadillas-Delgado
authors.forename: Tomás
authors.initials: T
authors.lastname: Martín
authors.forename: Oscar
authors.initials: O
authors.lastname: Fabelo
authors.forename: Jorge
authors.initials: J
authors.lastname: Pasán
authors.forename: Fernando S
authors.initials: FS
authors.lastname: Delgado
authors.forename: Francesc
authors.initials: F
authors.lastname: Lloret
authors.forename: Miguel
authors.initials: M
authors.lastname: Julve
authors.forename: Catalina
authors.initials: C
authors.lastname: Ruiz-Pérez
mesh_terms: D000085:Acetates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005682:Gadolinium / Q000737:chemistry*; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*
chemical_list: D000085:Acetates; D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D005682:Gadolinium