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

Six trinuclear CuMCu compounds (M = Cu, Ni, Co, Fe, Mn, Zn) derived from the Schiff base ligand, HL (2 + 1 condensation product of salicylaldehyde and -1,2-diaminocyclohexane) are reported in this investigation. The composition of the metal complexes are [{CuL(ClO)}Cu(HO)]·2HO (1), [{CuL(ClO)}{Ni(HO)}{CuL}]ClO·CHCOCH (2), [{CuL(ClO)}{Co(CHCOCH)(HO)}{CuL(CHCOCH)}]ClO (3) and isomorphic [{CuL(ClO)}M(CHOH)] (4, M = Fe; 5, M = Mn; 6, M = Zn). Two copper(ii) ions in 1-6 occupy NO compartments of two L ligands, while the second metal ion occupies the O(phenoxo) site provided by the two ligands, , the two metal ions in both CuM 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 ( = -2 type): = -136.50 cm and = 0.00 for the CuCuCu compound 1; = -22.16 cm and = -1.97 cm for the CuNiCu compound 2; = -14.78 cm and = -1.86 cm for the CuCoCu compound 3; = -6.35 cm and = -1.17 cm for the CuFeCu compound 4; = -6.02 cm and = -1.70 cm for the CuMnCu compound 5; = -2.25 cm for the CuZnCu compound 6 ( is between two Cu in the NO compartments; is between Cu and M through a diphenoxo bridge).