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 = -2 JS 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).