Stabilization of hexa-coordinated P(v) corroles by axial silyloxy groups.

We report the stabilization of the hexa-coordination environment for P(v) corroles by using alkyl/aryl substituted silyloxy groups as axial ligands. The P(v) corroles are highly fluorescent in a hexa-coordination environment compared to in a penta-coordination environment. However, P(v) corroles generally undergo axial ligand dissociation to form a mixture of penta- and hexa-coordinated P(v) corroles in non-coordinating solvents such as toluene, CH2Cl2, CHCl3. The usage of moderately bulkier and electron-donating silyloxy groups helps to restrict the axial ligand dissociation of silyloxy substituted hexa-coordinated P(v) corroles in non-coordinating solvents. The crystal structure confirmed the hexa-coordination geometry for the P(v) corroles. The P(v) corroles strongly absorb and emit in the visible region, with decent quantum yields and singlet state lifetimes. The hexa-coordinated P(v) corroles are highly stable under electrochemical conditions.