Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn)?

RSC Advances Pub Date: 2018-02-14 DOI: 10.1039/C7RA13763J

Abstract

Six trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn) derived from the Schiff base ligand, H2L (2 + 1 condensation product of salicylaldehyde and trans-1,2-diaminocyclohexane) are reported in this investigation. The composition of the metal complexes are [{CuIIL(ClO4)}2CuII(H2O)]·2H2O (1), [{CuIIL(ClO4)}{NiII(H2O)2}{CuIIL}]ClO4·CH3COCH3 (2), [{CuIIL(ClO4)}{CoII(CH3COCH3)(H2O)}{CuIIL(CH3COCH3)}]ClO4 (3) and isomorphic [{CuIIL(ClO4)}2MII(CH3OH)2] (4, M = Fe; 5, M = Mn; 6, M = Zn). Two copper(II) ions in 1–6 occupy N2O2 compartments of two L2? ligands, while the second metal ion occupies the O(phenoxo)4 site provided by the two ligands, i.e., the two metal ions in both CuIIMII pairs are diphenoxo-bridged. Positive ESI-MS of 1–6 reveals some interesting features. Variable-temperature and variable-field magnetic studies reveal moderate or weak antiferromagnetic interactions in 1–6 with the following values of magnetic exchange integrals (H = ?2JS1S2 type): J1 = ?136.50 cm?1 and J = 0.00 for the CuIICuIICuII compound 1; J1 = ?22.16 cm?1 and J = ?1.97 cm?1 for the CuIINiIICuII compound 2; J1 = ?14.78 cm?1 and J = ?1.86 cm?1 for the CuIICoIICuII compound 3; J1 = ?6.35 cm?1 and J = ?1.17 cm?1 for the CuIIFeIICuII compound 4; J1 = ?6.02 cm?1 and J = ?1.70 cm?1 for the CuIIMnIICuII compound 5; J = ?2.25 cm?1 for the CuIIZnIICuII compound 6 (J is between two CuII in the N2O2 compartments; J1 is between CuII and MII through a diphenoxo bridge).

Graphical abstract: Syntheses, crystal structures, magnetic properties and ESI-MS studies of a series of trinuclear CuIIMIICuII compounds (M = Cu, Ni, Co, Fe, Mn, Zn)
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