Cadmium diruthenium(ii,iii) carbonates showing diverse magnetism behavior arising from variety configuration of [Ru2(CO3)4]n3n− layer

Abstract

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)₄³⁻ 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]_n³ⁿ⁻ 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)₄³⁻ 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]_n³ⁿ⁻ 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.