KINETICS OF THE REACTION BETWEEN ZINC(II) AND TETRAKIS(2-FLUORO-3-SULFONATOPHENYL)PORPHYRIN

The kinetics of the reaction between Zn(II) ion and the peripherally n egatively charged tetrakis(2-fluoro-3-sulfonatophenyl)porphyrin (H(2)T 2FSPP) were investigated at 25 degrees C and 0.1 M ionic strength (NaN O3). The reaction was found to be first order in Zn(II) and porphyrin concentration. The rate of zinc ion incorporation was equal to k(1)[Zn 2+][H(2)T2FSPP], where k(1) = 0.349+/-0.002 M-1 sec(-1) at 25 degrees C and pH = 6.63. This rate is slower than the corresponding rates for the reaction of negatively charged tetrakis(p-sulfonatophenyl)porphyri n (H2TPPS) and a peripherally positively charged tetrakis(p-trimethyla mmoniumphenyl)porphyrin (H(2)TAPP). The reaction rate increased with a n increase in pH between 4.95 and 9.20.