Core size sensitive resonance Raman bands of metallooctaethyl and protoporphyrin complexes

✍ Scribed by Y.A. Sarma

• Book ID: 103907267
• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 347 KB
• Volume: 45
• Category: Article
• ISSN: 1386-1425
• DOI: 10.1016/0584-8539(89)80173-4

✦ Synopsis

The high frequency resonance Raman skeletal mode frequencies vl, vj, vi,,, v1 1 and y19 of iron complexes of metallooctaethyl porphyrins (MOEP) and metalloprotoporphyrins (MPP) are examined for their dependence on core size and methine bridge stretching force constants. The force constants of these complexes are estimated from a plot between the center-to-pyrrole nitrogen distances and the methine bridge stretching force constants of Ni, Co, Cu and Zn(OEP). Another plot between these constants and the skeletal mode frequencies of MOEP and MPP complexes confirm that as the porphyrin core size increases, the methine bridge stretching force constants are reduced and the skeletal mode frequencies are lowered. These structural correlations are used to determine the possible expansion, doming or ruffling of the porphyrin core of the complexes under study. Ferrous low spin complexes of OEP and PP and Ru"(OEP) (Py), show large deviations from these correlations, indicating strong metal-porphyrin n back-bonding.