Synthesis, structure and NLO properties of a 1,3,5-substituted tricationic cobaltocenium benzene complex

• Synthesis of a homonuclear, tricationic 1,3,5-cobaltocenium substituted benzene complex.
• Further proof of the importance of a 1D attribute to a octopolar 2D arrangement of donor/acceptor functions, in the context of organometallic NLO chromophores.
• Presumably, the cleavage of a Cp anion during the second reduction step (Co2+/Co+) leads to the separation of redox waves corresponding to the three cobalt centers.

Interested in the nonlinear optical properties of multinuclear metallocene-substituted complexes, we were successful in synthesizing the homotrinuclear coordination compound [1,3,5-tris(η5-2,4-cyclopentadien-1-yl)(η4-2,4-cyclopentadienyl-1-ethynyl)cobalt(I)]benzene (1) via a threefold nucleophilic addition to cobaltocenium cations. Upon hydride abstraction, the target compound [1,3,5-tris(η5-2,4-cyclopentadien-1-yl)(η5-2,4-cyclopentadienyl-1-ethynyl)-cobalt(III)]benzene tris(hexafluoridophosphate) (2) was obtained. Both complexes were fully characterized and, in continuation of previous investigations, investigated in terms of the influence of an octopolar arrangement of acceptor functions on the nonlinear optical activity of organometallic compounds.

Metallocenes can be utilized as acceptor, as well as donor functions in nonlinear optically (NLO) active compounds. We are investigating their influence as 1D- and 2D-attributes in organometallic NLOphores. The next puzzle piece, presented herein, is a strictly acceptor-substituted tricationic cobaltocenium complex.Metallocenes can be utilized as acceptor, as well as donor functions in nonlinear optically (NLO) active compounds. We are investigating their influence as 1D- and 2D-attributes in organometallic NLOphores. The next puzzle piece, presented herein, is a strictly acceptor-substituted tricationic cobaltocenium complex.Figure optionsDownload as PowerPoint slide