Transition metal complexes tropolones

The tropolones form transition-metal complexes of high affinity constants, for example [M(77 )3] with M = Co(n), Ni(H) and Zn(H), but M(77 )2 with M = Cu(II)2 . Moreover, these compounds form complexes with heavy metals (Os, Ir, Pt, Mo and W) , the lanthanides(in) and main-group metal ions (Ga, In, Sn, Sb and Pb) many have crystal structures determined and some show biological activities and potential... 

---