Fig. 4
Experimental evidence of subtle porphyrin ring distortion. a Resonance Raman spectra for compounds 1‒3 in the high frequency region recorded by exciting at 405 nm in dichloromethane at room temperature. With increasing chain lengths, the three bands centred at 1204, 1522–1523, and 1541–1542 cm–1 become prominent. b, c Eigenvectors calculated for the two Eu modes ν37 at 1535 cm–1 (b) and ν38 at 1545 cm–1 (c). These modes are associated with out-of-plane stretching of porphyrin ring. d Time-resolved fluorescence spectra of compounds 1‒3 collected at 40 ps of excitation, measured in toluene by exciting at 400 nm
