Reaction of zerovalent copper with cobalt(II) acetate and triethanolamine (H₃Tea) in DMF solution in air yields the unique pentanuclear mixed-valence complex [Cu^II ₂Co^IICO^III ₂(O₂CMe)₄(H₂Tea)₂(Tea)₂]·2(HO₂CMe), 1, which has been characterized by a range of spectroscopic methods and structurally by X-ray crystallography. In the centrosymmetric unit of 1 five metal ions are linked together by eight oxygen atoms of the four triethanolamine ligands and by two acetate anions in the sequence Cu(II)–Co(III)–Co(II)–Co(III)–Cu(II), with the metal–metal separations being 2.823(2) and 2.964(1) Å for Cu(II)···Co(III) and Co(III)···Co(II), respectively. Discrimination between Co(II) and Co(III) atoms is based on bond length considerations; the Co(III) is low spin. The lattice hydrogen-bonded network involving the non-coordinating acetic acid molecules links the pentanuclear units together and results in the formation of an extended one-dimensional structure. Magnetic measurements for 1 showed a marked decrease of the χT value at low temperature, indicative of antiferromagnetic interactions between magnetic centres. A fit was attempted assuming an effective S = 1/2 ground state for Co(II) and an Ising-type anisotropy, considering only intramolecular interactions. The obtained value for J_z of 36 cm⁻¹ must originate from the efficient role of the diamagnetic Co(III) in transmitting the interaction between Cu(II) and Co(II) below 40 K.

An unprecedented antiferromagnetic exchange mediated by two –O–Zn–O– bridges, with singlet–triplet splitting J = 35.0 cm⁻¹, was observed between two copper centers separated by 5.7062(9) Å in the heterometallomacrocyclic diethanolamine (H₂L) complex [Cu₂Zn₂(NH₃)₂Br₂(HL)₄]Br₂·CH₃OH.

Three kinds of Cd^II/Cu^II compounds of different nuclearity: tetranuclear [Cd₂Cu₂I₄L₄(dmso)₂] 1, pentanuclear [Cd₂Cu₃Br₆L₄(dmso)₂] 2 and hexanuclear [Cd₄Cu₂Cl₆L₆(H₂O)₂] 3, have been synthesised by the reaction of zerovalent copper and cadmium halides with non-aqueous (dmso, CH₃CN) solutions of 2-dimethylaminoethanol (HL) in air. The choice of counteranion in the initial cadmium salt provides a useful method of altering the nuclearity and structure of the heterometallic Cd/Cu complexes. Crystallographic investigations reveal that 1 has a centrosymmetric tetranuclear structure with a zig-zag Cd–Cu–Cu–Cd skeleton. The molecular structure of 2 consists of a pentanuclear centrosymmetric core in which four metal atoms are linked together by bridging oxygen atoms of L groups and bromide anions to form a parallelogram Cu–Cd–Cu–Cd centred on the fifth Cu. The hexanuclear complex 3 is made up of two symmetry-related units with triangular CuCd₂ cores linked by amino alkoxo bridges, involving cadmium centres of both units.