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The Construction of Open Gd III Metal–Organic Frameworks Based on Methanetriacetic Acid: New Objects with an Old Ligand
Author(s) -
CañadillasDelgado Laura,
Martín Tomás,
Fabelo Oscar,
Pasán Jorge,
Delgado Fernando S.,
Lloret Francesc,
Julve Miguel,
RuizPérez Catalina
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200903053
Subject(s) - crystallography , trigonal prismatic molecular geometry , lanthanide , octahedron , carboxylate , ligand (biochemistry) , chemistry , denticity , gadolinium , crystal structure , ion , metal organic framework , metal ions in aqueous solution , stereochemistry , adsorption , biochemistry , receptor , organic chemistry
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 μ‐ O (1) ; κ 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.