Mixed-Valent Diruthenium Diphosphonate with Kagomé Structure

Homo-valent diruthenium(II,II) carbonates Na4[Ru2(CO3)4]·10H2O: synthesis, structure, properties, and calculation

Homo-valent diruthenium(II,II) carbonates have been underexplored hitherto. This paper reports the synthesis and crystal structure of a diruthenium(II,II) compound, Na₄Ru₂(CO₃)₄·10H₂O (1). It has a two-dimensional structure in which the paddle-wheel diruthenium units of Ru₂(CO₃)₄^4- are cross-linked through the carbonate groups. The investigation of the primary magnetic properties and theoretical studies with density functional theory (DFT) reveal that weak antiferromagnetic interactions are propagated between the Ru₂ units which contain two unpaired electrons in an electron configuration σ²π⁴δ²π*²δ*² with a ground state S = 1. According to Raman spectrum measurements combined with theoretical calculations, the strong peak at 356 cm^-1 in the small-wavenumber region was assigned to the stretching of the Ru-Ru double bonds.

Grinding enhances the magnetic hardness of heterometallic diruthenium(ii,iii) carbonates with a kagome lattice structure

A manual grinding strategy promotes the magnetic hardness of Cs₃Cd(H₂O)₆[{Cd(H₂O)₃}₂{Ru₂(CO₃)₄}₃]·10H₂O with a kagome lattice structure.

Towards a new type of heterometallic system based on a paddle-wheel Ru2 dimer: first results derived from the use of a high spin diruthenium(iii,iii) building block

Heterometallic diruthenium(iii,iii) compound shows a two-step relaxation and order below 14 K with a coercive field of 24.9 kOe at 1.8 K.

Chlorine and temperature directed self-assembly of Mg-Ru2(ii,iii) carbonates and particle size dependent magnetic properties

A series of heterometallic magnesium diruthenium(ii,iii) carbonates, namely K{Mg(H2O)6}2[Ru2(CO3)4Cl2]·4H2O (1), K2[{Mg(H2O)4}2Ru2(CO3)4(H2O)Cl]Cl2·2H2O (2), K[Mg(H2O)5Ru2(CO3)4]·5H2O (3) and K[Mg(H2O)4Ru2(CO3)4]·H2O (4), were synthesized from the reaction of Ru2(CO3)4(3-) and Mg(2+) in aqueous solution. Compound 1 is composed of ionic crystals with the Ru2(CO3)4Cl2(5-) : Mg(H2O)6(2+) : K(+) ratio of 1 : 2 : 1. Compound 2 consists of two dimensional layer structures, in which each octahedral environment Mg(H2O)4(2+) bonds to two [Ru2(CO3)4(H2O)Cl](4-) units in a cis manner forming a neutral square-grid layer {Mg(H2O)4Ru2(CO3)4(H2O)Cl}n. For compound 3, one water molecule of each Mg(H2O)6(2+) is substituted by an oxygen atom of Ru2(CO3)4(3-) forming [Mg(H2O)5Ru2(CO3)4](-), and then the neighboring Ru2 dimers are linked together by the rest of the two oxygen atoms of carbonates to form a layer structure {Mg(H2O)5Ru2(CO3)4}n(n-). In compound 4, the neighboring squared-grid layers {Ru2(CO3)4}n(3n-), similar to those in compound 3, are linked by each octahedral environment Mg(H2O)4(2+) in a cis manner forming the three-dimensional network {Mg(H2O)4Ru2(CO3)4}n(n-). Compound 3 shows ferromagnetic coupling between Ru2 dimers, and a long-range ordering is observed below 3.8 K. Compound 4 displays a magnetic ordering below 3.5 K, and a systematic study of the size-dependent magnetic properties of compound 4 reveals that the coercivity of 4 has been improved with reduced sample particle size from the micrometer to the nanometer scale.

Isomeric chain structures of {[Mn(H₂O)₄]₂Ru₂(CO₃)₄Br₂}n(n-): syntheses, structural diversity and magnetic properties

The self-assembly of Ru2(CO3)4(3-) paddle-wheel precursors and Mn(2+) ions in aqueous solution yields various carbonate complexes. With appropriate selection of the synthetic conditions, we are able to intentionally tune the composition and structure of Mn-Ru2-carbonate assemblies to form infinite chain structural complexes, e.g., K[{Mn(H2O)4}2Ru2(CO3)4Br2]·H2O (1) and H[{Mn(H2O)4}2Ru2(CO3)4Br2]·6H2O (2). Complexes 1 and 2 are obtained at different temperatures (25 °C for 1 and 5 °C for 2, respectively), and their crystal structures consist of brick-wall stacked chains, in which neighboring Ru2(CO3)4Br2(5-) units are linked by two disubstituted octahedral Mn(H2O)4(2+) in a cis manner, resulting in two isomeric (twisted and zigzag) negative double-chain α- and β-{[Mn(H2O)4]2Ru2(CO3)4Br2}n(n-). The magnetic properties of complexes 1 and 2 were highly characterized. The alternating current (AC) susceptibility analysis of complex 1 reveals a two-step magnetism transition at T1 = 5.0 K and T2 = 2.6 K, respectively. Complex 2 exhibits metamagnetism behavior, with a transition field H(C) = ~1.2 kOe at 2.0 K.

Cadmium diruthenium(II,III) carbonates showing diverse magnetism behavior arising from variety configuration of [Ru2(CO3)4]n(3n-) layer

Two hetero-metallic carbonates, namely KCd(H2O)3Ru2(CO3)4·4H2O (1) and KCd(H2O)3Ru2(CO3)4·3.5H2O (2), have been synthesized in a neutral aqueous solution. Both of the 3D dimensional structured complexes contain mixed-valent diruthenium(II,III) carbonate paddlewheel cores of Ru2(II,III)(CO3)4(3-) that are connected to each other in trans- or cis-modes by carbonate oxygen atoms, forming rectangular square-grid and isomeric parallelogram layers [Ru2(CO3)4]n(3n-) in 1 and 2, respectively. The reaction temperature is found to play an important role in directing the final products with particular topologies and their layered structural diversity is due to the various linking modes between the Ru2(CO3)4(3-) units. The magnetic studies show that ferromagnetic interactions are propagated between the diruthenium units in both complexes 1 and 2 but their magnetic properties differ at low temperatures, in which the trans linking mode parallelogram layer [Ru2(CO3)4]n(3n-) in complex 2 leads to long-range magnetic ordering below 4.0 K. However, no Curie ordering down to 1.8 K is detected for complex 1 containing the isomeric rectangle square-grid layer linking in the cis mode.

A series of novel lanthanide carboxyphosphonates with a 3D framework structure: synthesis, structure, and luminescent and magnetic properties

By introduction of 1,4-benzenedicarboxylic acid as the second organic ligand, a series of novel lanthanide carboxyphosphonates with a 3D framework structure, namely, [Ln(3)(H(2)L)(HL)(2)(bdc)(2)(H(2)O)]·7H(2)O (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8); H(3)L = H(2)O(3)PCH(2)NC(5)H(9)COOH; H(2)bdc = HOOCC(6)H(4)COOH) have been synthesized under hydrothermal conditions. Compounds are isostructural and feature a 3D framework in which Ln(III) polyhedra are interconnected by bridging {CPO(3)} tetrahedra into 2D inorganic layers parallel to the ab plane. The organic groups of H(2)L(-) are grafted on the two sides of the layer. These layers are further cross-linked by the bdc(2-) ligands from one layer to the Ln atoms from the other into a pillared-layered architecture with one-dimensional channel system along the a axis. The thermal stability of compounds has been investigated. Luminescent properties of compounds , and the magnetic properties of compound have also been studied.

Diphosphates and diphosphonates in polyoxometalate chemistry

In the wide area of polyoxometalate (POM) chemistry, diphosphate/diphosphonate-based POMs represent a more recent area of study. However, in this short time it has emerged to become very dynamic, as shown by the wide variety of compounds reported. Ever since the discovery of the first polyoxotungstate framework constructed from diphosph(on)ate ligands, a widespread investigation on the preparative chemistry and properties of such compounds has followed. The main focus of such a study is based on factors such as the oxidation state of the metal, the effect of pH and temperature during synthesis, and the presence of different functional groups on the diphosphonate. In this review we discuss in detail all diphosphate/diphosphonate-based POMs, beginning with early developments, subsequent growth in interest, and finally focusing on the very latest developments.

Template- and pH-Directed Assembly of Diruthenium Diphosphonates with Different Topologies and Oxidation States

In the presence of organic templates, six diruthenium diphosphonates, namely, [H3N(CH2)3NH3]2[Ru2(hedp)2] (1), [H3N(CH2)4NH3]2[Ru2(hedp)2].4H2O (2), [H3N(CH2)5NH3]2[Ru2(hedp)2].4H2O (3), [H3N(CH2)3NH3][Ru2(hedp)(hedpH)].H2O (4), [H3N(CH2)4NH3][Ru2(hedpH(0.5))2].2H2O (5), and [H3N(CH2)5NH3]2[Ru2(hedp)2][Ru2(hedpH)2]] (6) [hedp = 1-hydroxyethylidenediphosphonate, CH3C(OH)(PO3)2] have been synthesized under hydrothermal conditions. Compounds 1-3 contain homovalent paddlewheel cores of Ru2(II,II)(hedp)2(4-) that are connected through edge-sharing of the [RuO5Ru] octahedra, resulting in infinite linear chains. Compounds 4-6 contain mixed-valent diruthenium(II,III) phosphonate paddlewheel cores of Ru2(II,III)(hedpH(n))2(3-2n)- that are connected by phosphonate oxygen atoms, forming distorted square-grid layers in 4 and 6 or a kagomé lattice in 5. Both the templates and the pH values are found to play important roles in directing the final products with particular topologies and oxidation states of the diruthenium unit. The magnetic studies show that weak antiferromagentic interactions are propagated between the homovalent diruthenium units in compounds 1-3. For compounds 4-6, weak ferromagnetic interactions are observed.

Molecular Geometry Directed Kagomé and Honeycomb Networks: Toward Two-Dimensional Crystal Engineering

We present here the formation of a molecular Kagomé network within a two-dimensional (2D) crystal on a surface. This system provides a clear example of how, by design, molecular geometry can be expressed at the level of the 2D crystal lattice, leading to the formation of open networks. Key elements to control molecular network formation are core symmetry, location and orientation of interacting and connecting substituents, as well as symmetry matching between the networks and the surface.