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

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.

Molecular Structures of the Products of a Diphosphonate Ester Building Block with Lewis Bases

By treating a suitable Wittig reagent under acid conditions, the phosphonate ester 1,4-bimethylenebenzene phosphonate ethyl ester (H₂[BBPE], 1) was obtained. As a building block, compound 1 has been reacted with the Lewis-base N,N-dimethylpiperazine, ammonia and NaOH yielded compounds 2–4. The crystal structures show that a 1D chain forming a tubular channel is constructed through hydrogen bonds in 1; hydrogen bonds form two 1D chains with left-hand and right-hand helixes and form 3D networks in compound 2; 1D hydrogen-bond chains are further connected together to afford a 3D network architecture in compound 3; the phosphonate is coordinated by two Na atoms which present different coordination environments in compound 4. Additionally, the relationships between the structure and fluorescence of the four compounds in the solid state and in different solvents have also been studied at room temperature.

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.

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.