Lanthanide-ion-tuned magnetic properties in a series of three-dimensional cyano-bridged Ln(III)W(V) assemblies.

The reaction of [W(CN)(8)](3-) with Ln(3+) and pyrazine in acetonitrile yielded a series of isostructural compounds formulated as Ln(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (Ln = La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6), Gd(7)). The Ln(III) and W(V) centers in the structure are linked through cyanide groups to form two-dimensional (2D) layers, which are further pillared by pyrazine, generating 3D frameworks. The magnetic behavior for compounds 1-7 were driven by the lanthanide ions involved. The Ln(III) and W(V) ions in compounds 2 and 5 are ferromagnetically coupled with magnetic ordering occurring at 2.8 K, comparable with magnetic ordering with the critical temperature of 1.9 K for compound 4. In addition, the antiferromagnetic interactions were observed in compounds 3 and 7, while no significant magnetic couplings were found in compounds 1 and 6.

Tetra-aqua-tetra-kis-(4,4'-bipyridine dioxide-κO)terbium(III) octa-cyanido-molybdate(V).

In the title compound, [Tb(C(10)H(8)N(2)O(2))(4)(H(2)O)(4)][Mo(CN)(8)], both metal atoms are eight-coordinated. The Tb(III) atom displays a dodecahedral geometry, while the Mo(V) ion exhibits a distorted square-anti-prismatic geometry. The Tb atoms are located on a special position of site symmetry [Formula: see text], whereas the Mo atoms are located on a twofold rotation axis. The cations are linked by O-H⋯O hydrogen bonds.

Two octacyanometallate-based Ni(II)W(V) bimetallic assemblies with metamagnetism.

Reactions of the precursors [Ni(macrocyclic ligand)](2+) with [W(CN)(8)](3-) afford two octacyanotungstate-based assemblies, (H(2)L(1))(0.5)[Ni(L(1))][W(CN)(8)]·2DMF·H(2)O (L(1) = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) (1) and [Ni(L(2))](3)[W(CN)(8)](2)·4H(2)O (L(2) = 3,10-dipropyl-1,3,5,8,10,12-hexaazacyclotetradecane) (2). Single crystal X-ray diffraction shows that 1 consists of anionic one-dimensional (1D) linear chains, while 2 is built of 2D graphite-like layers with (6, 3) topology. Magnetic studies reveal that both complexes exhibit metamagnetic behavior from the spin-canted antiferromagnet to the ferromagnet induced by field.

Efficient synthetic strategy to construct three-dimensional 4f-5d networks using neutral two-dimensional layers as building blocks.

The reaction of neutral two-dimensional (2D) layer Tb(H(2)O)(5)W(CN)(8) with pyrazine in the acetonitrile solution has led to a 3D bimetallic complex, Tb(H(2)O)(4)(pyrazine)(0.5)W(CN)(8) (1). In the structure of 1, the eight-coordinated W center adopts a slightly distorted dodecahedron, while the Tb center exhibits a nine-coordinated slightly distorted tricapped trigonal prism. The Tb(3+) atoms and the [W(CN)(8)](3-) units are linked in alternating fashion in the ab crystallographic plane, resulting in an infinite 2D corrugated layers. The linear bis-monodentate pyrazine ligands acting as pillars link adjacent layers along the c axis to form an extended 3D open framework. The possible formation mechanism is proposed, and the temperature has played a crucial role for the formation of 1. Magnetic measurements revealed the presence of ferromagnetic interaction between Tb(III) and W(V) centers. 1 marks the first structural pattern using the neutral 2D layer as building block and the first 3D complex with Ln(III)-[W(V)(CN)](8) found in octacyanometallate-based system. Such a novel and effective building-block methodology will provide a new attractive path forward in developing functionalities of 3D 4f-5d system and may provide an opportunity to obtain 3D magnet in 4f-5d assembly.

4,4'-Diazenediyldipyridinium 4-(4-pyridyldiazen-yl)pyridinium octa-cyanidotungstate(V) dihydrate.

The asymmetric unit of the title complex, (C(10)H(10)N(4))(C(10)H(9)N(4))[W(CN)(8)]·2H(2)O, contains two 4,4'-diazenediyldipyridinium, [H(2)(4,4'-azpy)](2+), two 4-(4-pyridyldiazen-yl)pyridinium, [H(4,4'-azpy)](+), cations, two [W(V)(CN)(8)](3-) anions, and four uncoordinated water mol-ecules. Each of the W centers is coordinated by eight CN groups in a slightly distorted square-anti-prismatic geometry. In the crystal structure, intra- and inter-molecular N-H⋯O, N-H⋯N and O-H⋯N hydrogen bonds link the cations and anions in an alternating fashion, forming a two-dimensional layered structure, in which they are further linked through the very weak π-π stacking inter-actions [shortest distance = 4.640 (2) Å] and van der Waals forces between adjacent layers, forming a three-dimensional supra-molecular network.