Control of dual emission behaviour of μ-oxo-bridged Si(IV) corrole dimers by substituent bulkiness

The μ-oxo-bridged dimer of Si(IV) corrole has been recently reported to exhibit dual emissive properties depending on the solvent-viscosity. Here we examined the control of the excited-state dynamics and dual emission by meso-aryl substituents. Less hindered 10-unsubstituted and 10-phenyl-5,15-bis(pentafluorophenyl)-Si(IV) corrole dimers and more hindered 5,15-bis(pentafluorophenyl)-10-(2,4,6-trimethoxy)phenyl-Si(IV) corrole dimer were newly prepared and characterised. Interestingly, their solid-state structures are different; parallel, anti-parallel or orthogonal. In contrast, the energy-minimized structures in the excited-state have been suggested to be parallel in all cases owing to the significant excimer-like stabilization. As a result, different emission behaviours and viscosity dependence were observed.