Search

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)43− and Mg2+ in aqueous solution. Compound 1 is composed of ionic crystals with the Ru2(CO3)4Cl25− : Mg(H2O)62+ : K+ ratio of 1 : 2 : 1. Compound 2 consists of two dimensional layer structures, in which each octahedral environment Mg(H2O)42+ 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)62+ is substituted by an oxygen atom of Ru2(CO3)43− 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}nn−. In compound 4, the neighboring squared-grid layers {Ru2(CO3)4}n3n−, similar to those in compound 3, are linked by each octahedral environment Mg(H2O)42+ in a cis manner forming the three-dimensional network {Mg(H2O)4Ru2(CO3)4}nn−. 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. [ABSTRACT FROM AUTHOR]

Isostructural heterometallic diruthenium carbonates KM(H2O)6[M(H2O)2Ru2(CO3)4Cl2]·4H2O [M = Zn (1) and Mn (2)] were synthesized from the reaction of the precursors [Ru2(CO3)4Cl2]5− and transitional metal ions in aqueous solution. Complexes 1 and 2 show layered structures in which Ru2(ii,iii) units are linked by four octahedral environment M(H2O)22+ ions in a cross fashion and vice versa giving a negative bimetallic square grid layer {M(H2O)2Ru2(CO3)4Cl2}n3n−. M(H2O)62+ ions, linked by K+ forming zigzag chain {KM(H2O)6}n3+, are located in the void spaces between the layers. The adjacent bimetallic carbonate layers are connected with K–O and K–Cl bonds, and hydrogen bonding, forming a supramolecular 3D framework structure. Their magnetic properties were characterized in detail, and intralayer ferromagnetic coupling between the Ru2 dimer and Mn2+ ion, as well as long-range ordering (Tc = 5.2 K) coexistence of domain movement behavior were observed for complex 2. [ABSTRACT FROM AUTHOR]

Self-assembly of Ru2(CO3)43− units and Cu2+ ions in the presence of halogen (Cl− or Br−) has resulted in two novel isomeric layered structural heterometallic carbonates, K2Li[Cu(H2O)2Ru2(CO3)4X2]·5H2O [X = Cl (1), Br (2)]. X-ray structural analysis reveals that complexes 1 and 2 contain a similar square-grid negative layer [Cu(H2O)2Ru2(CO3)4X2]n5n−, in which each Ru2(CO3)4X25− unit is linked by four Jahn–Teller distorted Cu(H2O)22+ ions in a cross mode and vice versa. The adjacent negative layers are connected by K–O, Li–O bonds, and hydrogen bonding, which led to the formation of a supramolecular 3D network structure. The two complexes show ferromagnetic coupling between the Ru2 dimer and the Cu2+ ion. Detailed magnetism measurement demonstrates that complex 1 exhibits soft magnetic ordering below 2.9 K coexistent with domain movement, and complex 2 shows long-range ferromagnetic ordering below 3.8 K. [ABSTRACT FROM AUTHOR]

The self-assembly of Ru 2 (CO 3 ) 4 3− and Zn 2 + in neutral aqueous solution forms heterometallic carbonate ZnHRu 2 (CO 3 ) 4 (H 2 O) 2 ·2H 2 O ( 1 ). X-ray crystallographic analysis and magnetic investigation show that 1 behaves as 2D antiferromagnetic layers. It is different from those light transitional metal d 1–9 centers (Mn, Co, and Ni), which merely exhibit octahedral MO 6 environment and trans - or cis -mode link Ru 2 dimers to form 2D and 3D frameworks, the production of 1 shows Zn 2 + adopting tetrahedral environment. Compared with Zn 2 + adopting octahedral environment in KZn(H 2 O) 6 [Zn(H 2 O) 2 Ru 2 (CO 3 ) 4 Cl 2 ]·4H 2 O, it proves that the axial position ligands (L) of Ru 2 dimers account for the tetrahedral ZnO 4 (L = H 2 O) or octahedral ZnO 6 (L = Cl − ) environments, and this is also due to the d 10 electronic configuration of Zn 2 + with the equivalent crystal field energy of the tetrahedral ZnO 4 and octahedral ZnO 6 symmetry. [ABSTRACT FROM AUTHOR]

Abstract: The temperature manipulation induces the aggregation of Ru2(CO3)4 3− paddle-wheel precursors and Mn2+ ions in lower temperature ~10°C forming layer structural complex, K[Mn(H2O)4Ru2(CO3)4]·5H2O (1). It composes of new negative layer {Mn(H2O)5Ru2(CO3)4} n n−, and magnetic exchanges between spin centers result in ordering below 3.8K. The observed critical temperature is like the previously reported 3D hetero-metallic carbonates H0.3K0.7Mn[Ru2(CO3)4](H2O)5.5, which demonstrates that it is independent of the interlayer connecting in such heterometallic complexes based on square-grid layer {Ru2(CO3)4} n 3n−. [Copyright &y& Elsevier]