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

Six trinuclear Cu(II)M(II)Cu(II) compounds (M = Cu, Ni, Co, Fe, Mn, Zn) derived from the Schiff base ligand, H(2)L (2 + 1 condensation product of salicylaldehyde and trans-1,2-diaminocyclohexane) are reported in this investigation. The composition of the metal complexes are [{Cu(II)L(ClO(4))}(2)Cu(II)(H(2)O)]·2H(2)O (1), [{Cu(II)L(ClO(4))}{Ni(II)(H(2)O)(2)}{Cu(II)L}]ClO(4)·CH(3)COCH(3) (2), [{Cu(II)L(ClO(4))}{Co(II)(CH(3)COCH(3))(H(2)O)}{Cu(II)L(CH(3)COCH(3))}]ClO(4) (3) and isomorphic [{Cu(II)L(ClO(4))}(2)M(II)(CH(3)OH)(2)] (4, M = Fe; 5, M = Mn; 6, M = Zn). Two copper(ii) ions in 1–6 occupy N(2)O(2) compartments of two L(2−) 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 Cu(II)M(II) 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 = −2JS(1)S(2) type): J(1) = −136.50 cm(−1) and J = 0.00 for the Cu(II)Cu(II)Cu(II) compound 1; J(1) = −22.16 cm(−1) and J = −1.97 cm(−1) for the Cu(II)Ni(II)Cu(II) compound 2; J(1) = −14.78 cm(−1) and J = −1.86 cm(−1) for the Cu(II)Co(II)Cu(II) compound 3; J(1) = −6.35 cm(−1) and J = −1.17 cm(−1) for the Cu(II)Fe(II)Cu(II) compound 4; J(1) = −6.02 cm(−1) and J = −1.70 cm(−1) for the Cu(II)Mn(II)Cu(II) compound 5; J = −2.25 cm(−1) for the Cu(II)Zn(II)Cu(II) compound 6 (J is between two Cu(II) in the N(2)O(2) compartments; J(1) is between Cu(II) and M(II) through a diphenoxo bridge).