Synthesis, structure, magnetic properties and DFT calculations of two hydroxo-bridged complexes based on MnIII(Schiff-Bases)

Abstract

Two hydroxo-bridged complexes, {[Mn^III(3-CH₃O)salen]₂[Cr^III(salen)(OH)₂]}ClO₄·6H₂O (1) and {[Mn^III(5-CH₃)salen]₂(OH)}ClO₄·3H₂O (2) [salen = N,N′-ethylenebis(salicylideneiminato) dianion], have been synthesized by the hydrolysis of the corresponding Mn^III(Schiff-Bases) derivatives and [Cr(salen)(H₂O)₂]Cl precursors. X-Ray structure characterization reveals the discrete linear arched trinuclear structure of 1 and the 1D chain arrangement of 2. Magnetic experimental data and density functional theory (DFT) calculations both indicate the dominant antiferromagnetic interaction mediated by the hydroxo-bridges in both 1 and 2. Frequency-dependent AC susceptibilities reveal slow relaxation of 1 in low temperature. It is worth noting that the structure and magnetic properties of 1 is comparable to a reported cyano-bridged SMM, K[(5-Brsalen)₂(H₂O)₂Mn₂Cr(CN)₆]·2H₂O.