Applying the Oligomer Approach to Luminescent Conjugated Organoboranes
摘要:
A series of highly luminescent monodisperse fluoreneborane oligomers (n = 1-6) were prepared using a new iterative synthetic procedure that takes advantage of the highly selective and differential reactivity of bromoboranes with arylsilanes and arylstannanes. Cyclic and square wave voltammetry revealed a gradual decrease of the LUMO energy levels with increasing chain length, while absorption and emission data showed a bathochromic shift and increase in quantum efficiency. An extended conjugation length of n(ECL) = S was derived.
Applying the Oligomer Approach to Luminescent Conjugated Organoboranes
摘要:
A series of highly luminescent monodisperse fluoreneborane oligomers (n = 1-6) were prepared using a new iterative synthetic procedure that takes advantage of the highly selective and differential reactivity of bromoboranes with arylsilanes and arylstannanes. Cyclic and square wave voltammetry revealed a gradual decrease of the LUMO energy levels with increasing chain length, while absorption and emission data showed a bathochromic shift and increase in quantum efficiency. An extended conjugation length of n(ECL) = S was derived.
A highly luminescent conjugated organoboron macrocycle containing six Lewis acidic boron centers was synthesized. Comparison of the optical and electronic properties with those of a hexameric linear oligomer revealed important differences due to delocalization within the highly symmetric cyclic conjugated structure. Exposure of this unique electron-deficient bora-cyclophane to fluoride or cyanide results in amplified fluorescence quenching and can be exploited to switch between an electron-deficient macrocycle and a highly charged, electron-rich borate cycle.