Synthesis, structure and magnetic properties of an inorganic-organic hybrid compound

Abstract

Hydrothermal reaction of a mixture of MnC₂O₄, H₃PO₃, piperazine and water at 423 K for 72 h resulted in a new inorganic-organic hybrid phase, [C₄N₂H₁₂][Mn^II ₂(HPO₃)₂(C₂O₄)], I. The structure comprises a network of Mn₂O₁₀ dimers, HPO₃ psuedo-tetrahedra and oxalate units, connected through their vertices forming a three-dimensional structure with one-dimensional channels. Protonated piperazine molecules are found in the channels. The formation of Mn(HPO₃)_∞ layers using only one type of secondary building unit, SBU-4, is noteworthy. Detailed magnetic investigations reveal that the antiferromagnetic layers are coupled in such a way to show magnetic polarizations on application of high magnetic field at low temperatures. This is unique and to the best of our knowledge has been observed for the first time in an open-framework solid.