Tetranuclear manganese complexes with [Mn~(II)_4] and [Mn~(II)_2Mn~(III)_2] units: Syntheses, structures, magnetic properties, and DFT study

摘要

Two tetranuclear manganese compounds, [Mn_4(μ3, η~2-L)_4Br_4-(LH)_4] (1) and [Mn_4(μ_3,η~2-L)2(μ,η~2-L) _4L_2Br_2] (2), with cubane and defect dicubane-like cores were synthesized and characterized by single-crystal X-ray diffraction, magnetic measurements, and DFT calculations (LH = 2-methoxyethanol). The magnetic properties of the resulting [Mn_4] building blocks are presented and discussed in detail. In particular, in 2 the MnIII-O-MnIII angle 103.12(8)° is the largest observed to date for such a system. The conjunction of antiferromagnetic and ferromagnetic interactions within the tetranuclear mixed-valent Mn~(II) 2Mn~(III) 2 complexes results in an unusual ST = 1 ground state.