MnO4- as a source of manganese in the direct synthesis of heterobimetallic Cu/Mn complexes

Complexes [Cu(en)2MnCl4] · Solv [en = ethylenediamine, Solv = DMF (1), DMSO (2)], [Cu(phen)2Cl]2[MnCl4] · DMF (3) and [Cu(phen)2Cl]2[Mn(phen)Cl3]Cl · 2H2O (4) [phen = 1,10-phenanthroline] have been synthesized by the interaction of copper metal with MnO4- in DMF, DMSO or CH3OH solutions of ethylenediamine or 1,10-phenanthroline. X-ray crystallographic studies of 1 and 2 have shown that the complexes included [Cu(en)2]2+ and [MnCl4]2− building blocks forming zigzag chains, which originate from H-bonding of DMF or DMSO guest molecules. In the crystal structures of 3–4, [Cu(phen)2Cl]+ cations and [MnCl4]2− (3) or [Mn(phen)Cl3]− (4) anions form 3D supramolecular frameworks through π–π stacking interactions between phen surfaces, C–H···Cl interactions and H-bonding supported by the solvent molecules.The EPR spectra of the polycrystalline compounds 1–3 are different as compared to spectrum for 4 due to the dominant effect of Mn(II) coordination geometry; tetrahedral in the former compounds and square pyramidal in the latter. The hyperfine splitting of frozen solution spectra indicates separation of the Mn(II) and Cu(en)22+ centers under the solvents influence.

A novel route for the preparation of the heterometallic complexes, in which MnO4- is used as a source of manganese, was successfully applied. Four previously unknown heterobimetallic Cu/Mn complexes have been obtained, their spatial structures determined by single crystal X-ray analysis, and X-band EPR spectra along with magnetic and thermal behaviors have been studied.Figure optionsDownload as PowerPoint slide