Grid-double-helicate interconversion.

An interconversion between a binuclear Cu(I) double helicate and a tetranuclear Cu(II) grid is reported. The passage from the Cu(I) double helicate to the Cu(II) grid occurs through oxidation of Cu(I) into Cu(II) or through displacement of Cu(I) by Cu(II). The conversion of the Cu(II) grid into the Cu(I) double helicate occurs through treatment of the grid with triflic acid, reduction of Cu(II) with ascorbic acid, and neutralization with triethylamine.

Modulation of self-assembly and magnetism of Cu(II) grids in solution.

Depending on the Cu(II)/ligand molar ratio, a pyrimidine-based ligand generates a tetranuclear grid (1/1) or a dinuclear stick (2/1). EPR, MS and visible spectroscopy studies suggest that dilution produces partial dissociation of the grid in solution. Replacement of 2-H-pyrimidine by a 2-phenyl-triazine unit prevents the dissociation of the grid.