Synthesis and Crystal Structure of Dissymmetrical Double Schiff Base Cu(II) Homobinuclear and Cu(II)-Mg(II)-Cu(II) Heterotrinuclear Complexes

Homobinuclear complex (HCuL)₂ (1) (H₃L: N-3-carboxylsalicylidene-N′-salicylaldehyde-1,2-diaminoethane) was obtained from self-organization of the reported complex HCuL, and its crystal structure was determined through X-ray diffraction at room temperature. The crystal of complex 1 belongs to monolinic system, the space group Cc, a=2.5326(5) nm, b=0.88861(18) nm, c=1.3738(3) nm, β=96.95(3)°, Z=4, R₁=0.0520, wR₂=0.1185. (HCuL)₂ is a dimeric molecule and has extended phenolic oxygen-bridged structure. In addition, using mononuclear complex HCuL as building blocks, Cu(II)-Mg(II)-Cu(II) heterotrinuclear complex 2 was synthesized, and its crystal structure also has been determined by X-ray analysis. The crystal of complex 2 is of monoclinic system, space group P_c, a=1.1816(2) nm, b=1.5599(3) nm, c=1.9642 (4) nm, β=98.22°, Z=2, R₁=0.0701, wR₂=0.1498. Each dissymmetrical cell unit of complex 2 contains two heterotrinucler neutral molecules: {[CuL(H₂O)]Mg[CuL(CH₃OH)]} and {[CuL]Mg[CuL(H₂O)]}.