Isomers of β-substituted di and tri-nitrotetraphenylporphyrins and their copper(II) derivatives: Structure, optical and electrochemical redox properties
- 32 Downloads
Controlled nitration ofmeso-tetraphenylporphyrinatocopper(II) using fuming nitric acid leads to the formation of different β-substituted nitro derivatives. Five isomers of dinitro and three isomers of trinitrotetraphenylporphyrins have been isolated and characterised using FAB/MS,1H NMR, UV-VIS and IR spectroscopies. The single crystal X-ray data on the copper(II) derivative of one of the isomers of trinitrotetraphenylporphyrin revealed ‘saddle’ conformation of the porphyrin core resulting from the nitro group substitution at theβ-pyrrole carbons. The electrochemical redox behaviour of the free-base porphyrins and their copper(II) derivatives revealed that successive substitution of nitro groups at the pyrrole carbons shifts the one-electron ring oxidations anodically while the ring reduction occurs at a less cathodic potential relative to the unsubstituted porphyrin. The isomer specific shifts in the redox potentials bear a direct relationship with the relative energy levels of HOMO/LUMO obtained from AM1 calculations.
KeywordsIsomers di and trinitrotetraphenylporphyrins ring-redox potentials crystal structure trinitrotetraphenylporphyrinatocopper(II)
Unable to display preview. Download preview PDF.
- 4.Tsuchiya S 1991J. Chem. Soc., Chem. Commun. 716Google Scholar
- 5.Dahal S, Nethaji M and Krishnan V 1994Acta Crystallogr. C50 314Google Scholar
- 7.Bartoli J F, Battioni P, De Foor W R and Mansuy D 1994J. Chem. Soc., Chem. Commun. 23Google Scholar
- 9.Catalano M M, Crossley M J, Harding M M and King L C 1984J. Chem. Soc., Chem. Commun. 1533Google Scholar
- 14.Sheldrick G M 1985SHELXS86: Program for the solution of crystal structure, Univ. of Gottingen, GermanyGoogle Scholar
- 15.Sheldrick G M 1993SHELXL93, Program for the refinement of crystal structures, Univ. of Gottingen, GermanyGoogle Scholar