Tris amine ligand system

A number of other acyclic ligand systems have been developed that use tris(aminoethyl)amine (tren) as a central unit (for macrobicycles... 

Chromium(II) complexes of bipyridyls, terpyridyl and the phenanthrolines have been discussed in Section 35.2.2.1. Complexes of the ligands 2-aminomethylpyridine (pic, 2-picolyl-amine) and 8-aminoquinoline (amq), which have one heterocyclic and one amino nitrogen donor atom, have been prepared by methods similar to those in Scheme 10. The bis(amine) complexes are typical high-spin, distorted octahedral complexes, and the mono(amine) complexes, from their antiferromagnetic behaviour and reflectance spectra, are six-coordinate, halide-bridged polymers (Table 15).103 No tris(amine) complexes could be prepared so the attempt to find spin isomeric systems in octahedral chromium(II) systems was unsuccessful ([Cr(en)3]X2 are high-spin and [Cr(bipy)3]X3 and [CrX2(bipy)2] low-spin). 

There are certain classes of coordination complexes that are particularly well characterized with amine ligands. Among these are the /r-peroxo and /r-superoxo Co111 complexes with general formula (N5)Co(02)Co(N5)"+, where Ns can be a variety of amine nitrogen donors3 42 and the tri-/r-hydroxo Co111 systems (N3)Co(OH)3Co(N3)3+.43... 

Fig. 16 Structures of the redox catalyst tris(l,10-phenanthroline-5,6-dione) ruthenium(II) perchlorate 1 and the mixed ligand system consisting of l,10-phenanthroline-5,6-dione and one N,N, A-tris(aminoethyl)amine ligand 2...

---