chemistry help

i am measuring paramagnetism in transition metal complexes for a chemistry investigation what octahedral complexes would give me good results? the ligand must remain constant only the transition metal can be altered.

PLease help thanks.

Not sure if this will be of any help but towards the middle of this page there is a link that has some info on octahedral complexes

http://wwwchem.uwimona.edu.jm/courses/magnetism.html