Aspects of investigating scrambling in the synthesis of porphyrins: different analytical methods

The porphyrin skelleton with a trans-A2B2 substitution pattern and NH-regions of 1H NMR spectra for mixtures of porphyrins. Each spectrum is recorded for a mixture of porphyrins and clearly show that the NH resonances depend on the meso-substituent. In comparison to other analytical methods used (e.g. HPLC and X-ray), the NMR method is superior for looking at product distributions from porphyrin synthesis.