A 2D rhomboidal system of manganese(ii) [Mn(3-MeC6H4COO)2(H2O)2]n with spin canting: rationalization of the magnetic exchange

Abstract

The crystal structure of Mn(II) carboxylate with 3-methylbenzoate as a bridging ligand [Mn(3-MeC₆H₄COO)₂(H₂O)₂]_n shows a rhomboidal layer, where each pair of neighbor Mn(II) ions are bridged through only one carboxylate group with a syn–anti conformation. The magnetic exchange between neighbor ions is weakly antiferromagnetic (J = −0.52 cm⁻¹, g = 2.04), and at low temperature the system shows spin canting with T_B = 3.8 K. Computational studies, based on periodic calculations of the energies of the significant spin states on the magnetic cell and some higher supercells, corroborate the weak AF interaction between the adjacent Mn(II) ions and preclude the negligible effect of frustration caused by very weak interactions between the non-adjacent ions in the magnetic response of the system. The results provide compelling evidence that the observed spin canting is due to the local coordination geometry of the manganese ions leading to two antiferromagnetically coupled subnets with different axial vectors.