Stannyl porphyrins

In terms of relative Co—C bond energies, those in the trihalomethyl complexes Co(OEP)CX3 are observed to be qualitatively weaker than in Co-alkyl porphyrin complexes. The high thermal stability of the cobalt porphyrin stannyl complexes was interpreted as an indication that, surprisingly, the Co—Sn bond is stronger than the Co—C bond in Co(Por)(alkyl) complexes. " ... 

Krebs and Spanggaard synthesized a zinc porphyrin, 2.142, which was linked to regioregular octi(3-hexylthiophene) by Stille-type coupling reaction of a stannyl derivative of the octithiophene and 5,15-dibromo-10,20-bis(3,5-di-fert-butylphenyl)zinc(II)porphyrin in 15% yield (Chart 1.28) [240]. Photovoltaic devices based on 2.142 showed a poorer photovoltaic response than devices based on simple oligothiophene, which was ascribed to the internal conversion of the energy absorbed by the Zn-porphyrin constituent. 

---