Bis(amidophenolate)-supported pnictoranides: Lewis acid-induced electromerism in a bismuth complex

Abstract

The synthesis of the complete series of 10-Pn-4 bis(amidophenolate)-supported pnictoranide anions is reported. Coordination of these anions to the cyclopentadienyliron(II) dicarbonyl fragment, [CpFe(CO)₂]⁺, delivers the corresponding 10-Pn-5 complexes for P, As and Sb, while in the case of Bi an electron redistribution takes place, and the corresponding 12-Bi-5 compound is isolated. This case of Lewis acid-induced electromerism has been experimentally confirmed through X-ray diffraction analyses as well as IR, UV-Vis and Mössbauer spectroscopy. Effective Oxidation State analysis of the Fe-complexes assigns an oxidation state +3 to all Pn, while it predicts the Fe-atom to be reduced to Fe(0) in the Bi-derivative. The mixture of the Bi(6p) orbital with the π-system of the bis(amidophenolate) ligand and the efficient electronic donation from this orbital to the Fe-center explain this situation.