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

Two hydroxo-bridged complexes, {[Mn-III(3-CH3O)salen](2)[Cr-III(salen)(OH)(2)]}ClO4 center dot 6H(2)O (1) and {[Mn-III(5-CH3)salen](2)(OH)}ClO4 center dot 3H(2)O (2) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized by the hydrolysis of the corresponding MnIII(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)(2)Mn2Cr(CN)(6)]center dot 2H(2)O.