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The structural, electronic, magnetic and theoretical study of the complex [Co3(HL)2(μ-AcO)2(AcO)2], 1, (HL is the dianion obtained by deprotonation of N,N’-bis(salicylidene)-2-hydroxy-1,3-propanediamine and AcO is acetate) shows that 1 crystallizes with two independent molecules in the asymmetric unit. Each molecule is a trinuclear complex. Both molecules have similar geometry, and correspond to a spin system based on trapped mixed valences on six-coordinate metal centres, CoIII(s=0)-CoII(s=3/2)-CoIII(s=0). The rigid framework formed by the tetradentate Salen-type ligands HL and the syn-syn bridging acetate anions is a characteristic feature observed in other related complexes. However, the here reported compound is the first one in this family having Z’>1. UV-Vis spectrum shows a broad band in the visible region where d-d transition for ions CoIII and CoII are. EPR spectra and the electronic energy estimations of the ground state show the presence of two conformers s=3/2. The χMT product at 300 K is 3.24 emu mol−1K per trinuclear unit, this product is expected for CoII where the contribution of orbital angular moment is taken into account (3.38 emu mol−1K for L=3). |
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