Abstract:
Spectroscopic analyses of boron-porphyrin complexes, synthesised by previously reported methods, have been performed using femtosecond transient absorption spectroscopy, fluorescence spectroscopy measurements, IR and Raman spectroscopy as well as DFT and TDDFT calculations. Transient absorption spectroscopy was used to study the dynamics of the transient species by exciting the molecule with a ~100 fs pulse of light at the wavelength corresponding to the Soret and Q band absorptions of those complexes and taking a spectrum at various time delays after the excitation. Porphyrin complexes of transition metals and many main group elements have been extensively explored in the past years due to the role they play in many important biological processes and their utilisation in various other fields. In recent years new boron-porphyrin complexes have been synthesised that exhibit features previously unobserved in porphyrin macrocycles.1 The most distinctive feature exhibited by these complexes is coordination of two boron atoms within the cavity of porphyrin macrocycle, where each boron atom is coordinated to two nitrogen atoms. This results in a large tetragonal elongation of the porphyrin ring along the B-B axis.2 The similarity in structure of some of the boron-porphyrin complexes to the BODIPY dyes used in fluorescent labelling is a feature that offers intriguing possibilities for the application of these complexes.