Structure and chemistry of N-substituted corroles and their rhodium(I) and zinc(II) metal-ion complexes.
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 [ZnII(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(pyr-role) distances of 1.956-1.987 A for the nonsubstituted sites, and 2.224-2.247 A for the substituted sites). These structural investigations also aid a good understanding of the spectroscopic characteristics of the derivatives.
Department of Chemistry and Institute of Catalysis Science and Technology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Liliya
L
Simkhovich
Parameswar
P
Iyer
Israel
I
Goldberg
Zeev
Z
Gross
D008024:Ligands; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D013057:Spectrum Analysis; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry*
D008024:Ligands; D009942:Organometallic Compounds; D011166:Porphyrins; C431863:corrole; D012238:Rhodium; D015032:Zinc