Journal of Porphyrins and Phthalocyanines 2001-12-31

Kinetics of zinc ion incorporation in base into a centrally aprotic beta-octabrominated cationic water-soluble porphyrin and its monolithium complex

Sabrina L. Bailey, P. Hambright

Index: 10.1002/jpp.549

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Abstract

The kinetics of zinc incorporation from pH 12 to 13 into the centrally aprotic BrP(4)2+ form of beta-octabromo-meso-tetrakis(N-methyl-4-pyridyl)porphyrin and its monolithium complex were studied at 25.0 °C, ionic strength (I) = 0.10. The reactions were first order in porphyrin and total zinc concentrations. For BrP(4)2+, the specific rate constant was 5.1 × 105 M−1 s−1 for Zn(OH)2aq, 9.9 × 104 M−1 s−1 for , and was unreactive. The Li-BrP(4)3+ complex had a formation constant with BrP(4)2+ of 1.1 × 103 M−1 from both kinetic and equilibrium measurements. In solutions containing both BrP(4)2+ and Li-BrP(4)3+, zinc incorporation proceeded only through BrP(4)2+. Copyright © 2001 John Wiley & Sons, Ltd.