Novel dinucleating ligand systems containing two adjacent coordination compartments of the potential triamidoamine-type-nickel(II) and cobalt(II) coordination chemistry

The preparation of novel dinucleating pyrazolate ligands H5L3 - H5L8 carryi ng chelating side arms with appending secondary amine functions is reported . Following different synthetic routes, either CH2CF3, C6H2F3, or C6F5 moie ties can be introduced as substituents at the terminal nitrogen atoms. Thes e systems are reminiscent of two coupled coordination compartments of the p otential triamidoamine-type. Crystallographic analyses of a series of bimet allic complexes of the CH2CF3-substituted ligand H5L4 with NiCl2 and CoCl2 reveal manifold coordination modes in the solid state, resulting from the f acile detachment of a single or several N-donor sites from the metal center s. Coordination number sets {4/6} (in (H5LCo2Cl4)-Co-4) and {5/6} (in (H4LN i2Cl3)-Ni-4 (H4LCo2Cl3)-Co-4 and (H5LNi2Cl4)-Ni-4) are thus observed. In th e non-deprotonated H5L-type systems the remaining protons are found to be s cavenged by a pyrazolate-N (in H5L4 Ni2Cl4) Or an amine function of a ligan d side arm (in (H5LCo2Cl4)-Co-4).