A very bulky carboxylic perchlorotriphenylmethyl radical as a novel ligand for transition metal complexes. A new spin frustrated metal system.

Reaction of a carboxylic perchlorotriphenylmethyl radical with Cu2(O2CCH3)(4).2H2O using different molar ratios yields two different transition metal complexes with strong intramolecular antiferromagnetic interactions, which in the case of complex 2 follows a butterfly spin frustrated model.