Structural and magnetic properties of spin-1/2 dimer compound Cu₂(IPA)₂(DMF)(H₂O) with a large spin gap

Abstract

We present the synthesis and a detailed investigation of structural and magnetic properties of metal-organic compound Cu2(IPA)2(DMF)(H2O) by means of x-ray diffraction, magnetization, and heat capacity measurements. Single crystals of the title compound were synthesized by judicious selection of organic ligand and employing a selective hydrothermal reaction route. It crystallizes in an orthorhombic structure with space group Cmca. The structural analysis revealed that two Cu 2+ ions are held together by the organic component (-O-C-O-) in a square paddle-wheel to form spin dimers which are aligned perpendicular to each other and are further coupled through organic ligands (isophthalic acid) forming two-dimensional layers. Temperature dependent magnetic susceptibility χ(T ) could be described well using spin-1/2 dimer model. The spin susceptibility χspin(T ) shows an exponential decrease in the low temperature region, below the broad maximum, confirming the singlet ground state with a large spin gap of ∆/kB 409 K. The heat capacity Cp measured as a function of temperature also confirms the absence of magnetic long-range-order down to 2 K.

Stable Inner 2H Tautomer of N-Confused-like Porphyrin Embedded with a Carbazole Subunit: Synthesis, Metal Coordination, and Magnetic and Anion Sensing Studies

“…Further evidence for paramagnetism is obtained from the magnetic isotherm ( M vs H ) measurement at T = 2 K (inset of Figure a). The behavior of M vs H curve resembles the behavior of a Brillouin function, typical of a paramagnet . Moreover, the value of M saturates to a value of 0.9 μ B , which is close to the expected value 1 μ B for a spin-1/2 Cu 2+ ion.…”

“…The behavior of M vs H curve resembles the behavior of a Brillouin function, typical of a paramagnet. 46 Moreover, the value of M saturates to a value of 0.9 μ B , which is close to the expected value 1 μ B for a spin-1/2 Cu 2+ ion. Thus, we conclude that the Cu 2+ spins in this compound are isolated and behave collectively as a paramagnet.…”