Tetranuclear mixed-metal MII2CuII2 complexes derived from a phenol-based macrocyclic ligand having two N(amine)2O2 and two N(imine)2O2 metal-binding sites

The reaction of N,N ' -dimethyl-N,N'-ethylenebis(5-bromo-3-formyl-2-hydroxybenzylaminato)copper(II) with ethylenediamine in aqueous DMF with excess perchloric acid resulted in the [2:2] cyclic condensation of: the constituents, providing the dinuclear Cu-II complex [Cu-2(H2R)I(ClO4)(2). It crystallizes in the monoclinic space group P2(1)/c, with a 19.603(3) Angstrom, b = 13.370(2) Angstrom, c = 21.072(3) Angstrom, beta = 98.87(1)degrees, V = 5456(1) Angstrom (3),: and Z = 4. The ligand R4- has two N(amine)(2)O-2 and two N(imine)(2)O-2 metal-binding sites sharing two phenolic oxygens, and [Cu-2(H2R)](ClO4)(2) has the two Cu-II ions in the N(imine)(2)O-2 sites and two, protons in the N(amine)(2)O-2 sites. [Cu-2(H2R)](ClO4)(2) was converted by neutralization into [Cu-2(R)], from which mixed-metal (Cu2M2II)-M-II complexes [Cu2M2(R)Cl-4] (M = COII, Ni-II, Zn-II) were derived. [Cu2Co2(R)Cl-4]. 2CHCl(3).H2O crystallizes in the monoclinic space group C2/c, with a = 32.514(3) Angstrom, b = 12.246(3) Angstrom, c = 19.827(2) Angstrom, beta = 126.682(1)degrees, V = 6380(1) Angstrom (3), and Z = 4. [Cu2Zn2(R)C-4]. 2CHCl(3).H2O crystallizes in the monoclinic space group C2/c, with a = 32.53(1) Angstrom, b = 12.242(2) Angstrom, c = 19.729(9) Angstrom, beta = 26.03(3)degrees, V = 6354(4) Angstrom (3), and Z = 4. The two complexes are isotructural and have a dimer-of-dimers structure with two separated (CuMnII)-Mn-II units. In each dinuclear unit, the Cu-II is bound to the N(imine)(2)O-2 site and the Mn is bonded to a phenolic oxygen and two nitrogens of the N(amine)(2)O-2 site. The Cu-II and M-II ions are bridged by a phenolic oxygen and an exogenous chloride ion. The (Cu2Ni2II)-Ni-II complex has a defect double-cubane structure. Cryomagnetic studies for the Ci(2)(II)Co(2)(II) complex indicate an antiferromagnetic spin-exchange interaction within each dinuclear (CuCoII)-Co-II unit (J = -9.5 cm(-1) based on H = -2JS(Cu)S(Co)). The (Cu2Ni2II)-Ni-II complex shows a weak antiferromagnetic interaction between the adjacent Cu-II and Ni-II ions (-3.5 cm(-1)) and a weak ferromagnetic interaction between the two Ni-II ions (+2.0 cm(-1)).