Syntheses, structures and magnetic properties of trinuclear Cu ~(11)M~(11)Cu~(11) (M = Cu, Ni, Co and Fe) and Tetranuclear [2×1+1×2] Cu~nMn~n2Cu~n complexes derived from a compartmental ligand: The schiff Base 3-Methoxysalicylaldehyde diamine can also stabilize a cocrystal

摘要

The present investigation describes syntheses, characterization and studies of the mononuclear compound [Cu~(11)LC (H_2O)] (1), the triangular, trinuclear monophenoxido-bridged compounds [{Ci~(II)L} _2M~(II)(H_2o)_2](Clo_4) _2.nH_2O [2 (M = Cu, n = 0), 3 (M = Ni, n = 3), 4 (M = Co, n = 0), 5 (M = Fe, n = O)] and the tetrametallic self-assembled complex [(Cu ~(II)LMn~(II)(H_2O)_3)(Cu ~(II)L)_2] (ClO_4)_2-H_2O (6) derived from compartmental Schiff base ligand, H2L, which is the [2+1] condensation product of 3-m.ethoxysalicylaldehyde and trans-l.,2-diaminocy clohexane. Single-crystal X-ray structures of 2, 5 and. 6 were determined. Two pairs of terminal-central metal ions in the trinuclear cores in 2 and 5 are monophenoxido-bridged. Interestingly, the CuO_6 and FeO_6 environments have tetragonally compressed octahedral geometries. On the other hand, the structure of 6 reveals that it is a [2×1+1×2] cocrystal of one diphenoxido-bridged dinuclear [Cu~(II)LMn~(II)(H _2O)_3]~(2+) dication and two mononuclear [Cu ~(II)L] moieties. Cocrystallization in 6 takes place as a result of water encapsulation. The variabletemperature (2-300 K) magnetic susceptibilities of compounds 2-6 have been measured. The exchange integrals obtained are: the Cu~(II)_3 compound 2, J = -78.9 cm~(-1) the Cu ~(II)Ni~(II)Cu~(II) compound 3, J = -22.8 cm ~(-1) the Cu~(II)Co~(II)Cu~(II) compound 4, J = -7.8 cm~(-1) the Cu~(II)Fe~(II)Cu~(II) compound 5,J = -3.0 cm.~(-1); the Cu~(II)_3Mn~(II) compound 6,J = -15.1 cm-1. The monophenoxido-bridging core in 3 and 4 has been proposed after comparison of the structures and magnetic properties of these two compounds with those of 2, 5 and related other compounds. This paper presents rare examples of monophenoxido-bridged Cu~(II)M ~(II)Cu~(II) (M = Cu, Ni, Co and Fe) compounds, provides an understanding of the structures from magnetic exchange integrals, and, most importantly, reports on the first example of a cocrystal derived from, a 3-meth.oxysalicylaldehyde diamine compartimentai ligand.