Structural and photophysical characterization of a tin(IV) porphyrin-rhenium(I)(diimine) conjugate

We report here the synthesis, solution and solid state (single crystal X-ray structure) of a novel robust conjugate, obtained via axial coordination of two Re(diimine) fragments to one tin(IV) porphyrin center. The photophysical behavior of the conjugate was investigated by emission and absorption time resolved experiments. The conjugate exhibits distinctive supramolecular features, different from those of the molecular components. Upon excitation of the Re(I)(diimine) units, the typical rhenium MLCT emission is completely quenched and efficient sensitization of the Sn-porphyrin triplet state occurs. The synthetic method proposed here may be easily extended to the facile and efficient obtainment of a large number of tin(IV) porphyrin–Re(diimine) conjugates, with tuned photophysical features.