A Tetrapyrrole Macrocycle Displaying a Multielectron Redox Chemistry and Tunable Absorbance Profile
AJ Pistner, GPA Yap, and J Rosenthal – The Journal of Physical Chemistry C, 116 (32), p 16918–16924.
Porphyrins are attractive chromophores for incorporation into light harvesting devices. Some of the most efficient porphyrin derivatives in this regard are synthetically complex platforms with specially tailored electronic properties. This work details the unique geometric and electronic structure of the phlorin framework. X-ray crystallography and NMR spectroscopy demonstrate that unlike typical tetrapyrrole macrocycles, the phlorin is not aromatic. These unusual electronics are manifest in distinct photophysical and redox properties, as the phlorin displays a rich multielectron redox chemistry. The phlorin also displays an intriguing supramolecular chemistry and can reversibly bind up to 2 equiv of fluoride in cooperative fashion. Accordingly, this synthetically accessible sensitizer displays a rich multielectron redox chemistry, excellent spectral coverage, and an intriguing anion binding chemistry that distinguishes this system from more commonly studied porphyrinoids… UV–vis Absorption Experiments UV/visible absorbance spectra were acquired on a StellarNet CCD array UV–vis spectrometer using screw-cap quartz cuvettes (7q) of 1 cm path length from Starna. All absorbance spectra were recorded at room temperature. View PDF.