C3-symmetric trinuclear copper(ii) species as tectons in crystal engineering

Abstract

Three new complexes have been obtained using C₃-symmetric trinuclear complexes as tectons; [Cu₃(felden)(NCS)₃(dmf)₃] (1), [Cu₃(felden)(mand)₃]·(C₂H₅)₂O (2), and [Cu₃(felden)(dca)₃(C₂H₅OH)]·2H₂O (3) (H₃felden is the Schiff base resulting from the condensation of 2,4,6-triformylphloroglucinol with N,N-dimethylethylenediamine, mand⁻ is the anion of the R-mandelic acid and dca⁻ is the dicyanamide anion). Compounds 1 and 2 are discrete trinuclear species, while compound 3 is a 2D coordination polymer, constructed from trinuclear nodes and dicyanamido spacers. The variable-temperature magnetic properties of 1–3 have been investigated and they reveal the occurrence of weak antiferromagnetic interactions between the copper(II) ions (−J values ranging from 0.90 to 2.40 cm⁻¹) whose size and trend are dependent on the intramolecular copper–copper separation and nature of the basal chromophore at each copper atom.