Core-size marker resonance Raman bands of metallotetraphenylporphines

Resonance Raman spectra are reported for Ni(II), Cu(II), Pd(II) and Pt(II) tetraphenylporphine (TPP). Systematic examination of the resonance Raman frequencies of these and of previously reported TPP derivatives has revealed three bands which exhibit a linear correlation with porphyrin core size (Ct–N), near 1460 cm−1 (polarized), 1540 cm−1 (anomalously polarized) and 1570 cm−1 (polarized). Parameters derived from the correlations indicate a reasonable similarity between these TPP modes and those of biological‐type metalloporphyrins which also correlate with Ct–N.