We recently reported the synthesis and characterization of ruthenium “picnic-basket” porphyrin carbonyl complexes. These synthetic tetraarylporphyrins bear a rigid superstructure that defines a molecular cavity on one face of the porphyrin macrocycle. Photolysis of these carbonyl complexes in a coordinating solvent results in formation of bis-solvent complexes. The bis(pyridine) complex has been structurally characterized. General methods to control axial ligation in these ruthenium picnic-basket porphyrins are presented. A transient pentacoordinate ruthenium picnic-basket porphyrin, which reversibly binds both dinitrogen and dioxygen within the protected cavity, has been prepared. The N2 and 02 complexes have been characterized by UV-visible, 1H NMR, and IR spectroscopies. The diamagnetic dioxygen complex shows ν(16O-16O) at 1103 cm−1 and thus is described as containing coordinated superoxide ion. A correlation between dioxygen binding and the Ru(III/II) potential was observed.
ASJC Scopus subject areas
- Colloid and Surface Chemistry