Molecular aggregates between octaethyltetrathiaporphyrin dication (OTP2+) and octaethylporphyrin (H2OEP) and its metal complexes

Atif Mahammed, Mordecai Rabinovitz, Roy E. Hoffman, Itamar Willner*, Emanuel Vogel, Michael Pohl

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The octaethyltetrathiaporphyrin dication, OTP2+, forms 1:1 intermolecular donor–acceptor complexes with NiII‐, VIVO‐ and FeIII‐octaethylporphyrins. The association constants of the complexes are governed by the oxidation potential of the metallo‐octaethylporphyrins and by secondary electrostatic interactions. Octaethylporphyrin, H2OEP, forms intermolecular complexes with OTP2+. Kinetic analyses of the formation of the various complexes revealed the formation of a primary complex exhibiting the stoichiometry (OTP2+)2(H2OEP). This intermolecular complex transforms into a thermodynamically stabilized intermolecular assembly with a stoichiometry corresponding to (OTP2+)4H2OEP. The activation barrier associated with the conversion of the primary complex to the thermodynamically stabilized assembly is Ea = 16·5 kcal mol−1 (1 kcal = 4·184 kJ). The association constant of the complex (OTP2+)2(H2OEP) is K1 = 1·3 × 1010 M−2 and the equilibrium constant between the two coexisting intermolecular complexes (OTP2+)4(H2OEP) and (OTP2+)2(H2OEP) is K2 = 7·4.

Original languageEnglish
Pages (from-to)659-670
Number of pages12
JournalJournal of Physical Organic Chemistry
Volume8
Issue number10
DOIs
StatePublished - Oct 1995

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