Abstract
In the present work we report on the detailed structural features of the chiral N21- and N22-substituted benzyl and picolyl derivatives of tris(pentafluorophenyl)corrole [H3(tpfc)]. The main difference between the isomers is that substitution on N22 creates a much more crowded environment, reflected in higher deformation of the corrole ring from planarity and of the meso-aryls from perpendicular orientation. The effects of metal-ion chelation on corrole geometry are demonstrated by structural investigations of the zinc(II) and rhodium(I) complexes of the N21- and N22-alkylated corroles. The major finding is the intramolecular coordination of the pyridine moiety of the picolyl substituent in the case of [Zn11(N21-picolyl-tpfc)]. This pyridine is readily attracted to the zinc ion as an axial ligand, thus replacing the external pyridine molecule of the precursor [ZnII(N21-benzyl-tpfc)(py)]. The change is associated with a considerable flattening of the corrole ring in order to allow a more convenient coordination of the zinc ion to all four pyrrole nitrogen atoms (at Zn-N(pyrrole) distances of 1.956 - 1.987 Å for the nonsubstituted sites, and 2.224 - 2.247 Å for the substituted sites). These structural investigations also aid a good understanding of the spectroscopic characteristics of the derivatives.
Original language | English |
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Pages (from-to) | 2595-2601 |
Number of pages | 7 |
Journal | Chemistry - A European Journal |
Volume | 8 |
Issue number | 11 |
DOIs | |
State | Published - 3 Jun 2002 |
Keywords
- Chelates
- Chirality
- Corroles
- Rhodium
- Zinc