Experimental and computational characterisation of an artificial light harvesting complex

Area of Science:

• Artificial photosynthesis
• Photophysics
• Supramolecular chemistry

Background:

• Natural photosynthesis utilizes efficient energy transfer mechanisms.
• Artificial light harvesting complexes (LHCs) aim to replicate these natural processes.
• BODIPY pillar[5]arene is a potential candidate for artificial LHCs, but requires thorough characterization.

Purpose of the Study:

• To experimentally and computationally investigate the photophysical properties of the BODIPY pillar[5]arene LHC.
• To compare the light absorption of the BODIPY LHC with individual BODIPY chromophores.
• To assess the suitability of BODIPY pillar[5]arene as an artificial LHC.

Main Methods:

• Experimental measurement of light absorption spectra.
• Computational analysis of molecular orbital couplings.
• Comparison of spectral data between the complex and individual chromophores.

Main Results:

• Evidence of quantum coherence with oscillation frequencies at 100 cm⁻¹ and 600 cm⁻¹, attributed to vibronic coupling.
• Computational analysis revealed strong molecular orbital couplings due to stacked BODIPY units.
• A 40% reduction in light absorbance for the BODIPY LHC compared to individual chromophores was observed, attributed to electronic interactions.

Conclusions:

• The BODIPY pillar[5]arene complex exhibits quantum coherence and unique photophysical properties.
• Electronic interactions between BODIPY units and the pillar[5]arene backbone influence light absorption.
• Further investigation is warranted to optimize BODIPY pillar[5]arene for artificial light harvesting applications.