title: Triangular oxalate clusters [W(3)(mu(3)-S)(mu(2)-S(2))(3)(C(2)O(4))(3)](2)(-) as building blocks for coordination polymers and nanosized complexes.
abstract: The reaction of aqueous [W3S7(C2O4)3](2-) with Ln(3+) and Th(4+) in a 1:1 molar ratio leads to oxalate-bridged heteropolynuclear molecular complexes and coordination polymers. La(3+) and Ce(3+) give a layered structure with big (about 1.8 nm) honeycomb pores which are filled with water molecules and lanthanide ions, in {[Ln(H2O)6]3[W3S7(C2O4)3]4}Br x xH2O (Ia and Ib). The smaller Pr(3+), Nd(3+), Sm(3+), Eu(3+), and Gd(3+) ions give discrete nanomolecules [(W3S7(C2O4)3Ln(H2O)5)2(mu-C2O4)] (with a separation of about 3.2 nm between the most distant parts of the molecule), which are further united into zigzag chains by specific S2...Br- contacts to achieve the overall stoichiometry K[(W3S7(C2O4)3Ln(H2O)5)2(mu-C2O4)]Br.xH2O (IIa-IId). Th(4+) gives K2[(W3S7(C2O4)3)4Th2(OH)2(H2O)10] x 14.33H2O (III) with a nanosized discrete anion (with a separation of about 2.7 nm between the most distant parts of the molecule), in which two thorium atoms are bound via two hydroxide groups into the Th2(OH)2(6+) unit, and each Th is further coordinated by five water molecules and two monodentate [W3S7(C2O4)](2-) cluster ligands. All compounds were characterized by X-ray structure analysis and IR spectroscopy. Magnetic susceptibility measurements in the temperature range of 2-300 K show weak antiferromagnetic interactions between two lanthanides atoms for compounds IIa, IIb, and IId. The thermal decomposition of Ia, Ib, and IIb was studied by thermogravimetry.
authors.affiliation: Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Lavrentiev Avenue 3, Novosibirsk 630090, Russia. caesar@che.nsk.su
authors.forename: Maxim N
authors.initials: MN
authors.lastname: Sokolov
authors.forename: Artem L
authors.initials: AL
authors.lastname: Gushchin
authors.forename: Konstantin A
authors.initials: KA
authors.lastname: Kovalenko
authors.forename: Eugenia V
authors.initials: EV
authors.lastname: Peresypkina
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Virovets
authors.forename: Joaquin
authors.initials: J
authors.lastname: Sanchiz
authors.forename: Vladimir P
authors.initials: VP
authors.lastname: Fedin
mesh_terms: D008280:Magnetics; D053758:Nanoparticles; D010070:Oxalates / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
chemical_list: D010070:Oxalates; D011108:Polymers