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Lanthanide(III) bis(porphyrin) sandwich complexes of octaethyltetraazaporphyrin (OETAP) were synthesized and characterized by UV-vis, IR, and NMR spectroscopies. Cyclic voltammetry results indicate that these neutral sandwich complexes are very easily reduced. Charge-transfer reactions were performed in solution with Ln-(OETAP)2 sandwiches and zirconium(IV) bis(porphyrin) sandwiches. The lanthanide sandwiches partially oxidize the zirconium sandwiches in solution, and a solvent dependence of the charge-transfer reaction was observed. The solid-state properties of these charge-transfer materials were also studied. Magnetic susceptibility results suggest weak intermolecular interactions between the sandwiches. The conductivities of the charge-transfer species are greatly improved relative to those of the insulating undoped sandwiches, but the conductivities are in the lower semiconducting region. The low conductivity values are thought to be due to poor intermolecular overlap.

A family of bis(porphyrin) zirconium sandwich complexes containing octaethylporphyrin (OEP) and octaethyltetraazaporphyrin (OETAP) was synthesized and characterized by UV−vis and NMR spectroscopies. The two ligands are structural analogues yet have dramatically different redox properties (the redox potentials of OETAP complexes are much more positive than those of the corresponding OEP complexes). Cyclic voltammetry results indicate that Zr(OETAP)2 is about 600 mV harder to oxidize and about 600 mV easier to reduce than Zr(OEP)2, while the mixed sandwich Zr(OEP)(OETAP) exhibits intermediate redox potentials. The structures of Zr(OEP)(OETAP) and Zr(OETAP)2 were determined by X-ray crystallography and compared to Zr(OEP)2. The solid-state structures were very similar, indicating that OEP and OETAP have similar steric parameters and that observed spectroscopic and electrochemical differences are due primarily to electronic factors. The one electron oxidized porphyrin sandwiches were also synthesized. Charact...