Co-ordination behaviour of a novel tristhiourea tripodal ligand; structural variations in a series of transition metal complexes

The co-ordination chemistry of a tristhiourea tris(2-pyridylmethyl)amine ligand () with a series of transition metal ions has been investigated. Crystallographic data show that large metal ions, with no geometrical preferences, such as Mn(ii) and Cd(ii), will form seven co-ordinate monocapped octahedral complexes, while smaller metal ions such as Zn(ii) favour five co-ordinate trigonal bipyramidal structures. In a similar manner to the related bisthiourea complexes, the Ni(ii) complex shows a strong preference for octahedral geometries resulting in the ligand binding asymmetrically. Spectroscopic (IR and NMR), spectrometric (MS) as well as electrochemical data for these complexes are reported.