SYNTHESIS AND O-2-BINDING PROPERTIES OF TETRAPHENYLPORPHYRINATOIRON(II) DERIVATIVES BEARING A PROXIMAL IMIDAZOLE COVALENTLY BOUND AT THE BETA-PYRROLIC POSITION

5,10,15,20-Tetrakis(o-pivalamidophenyl)porphyrins (TPVP) and their iro n(II) derivatives bearing a proximal imidazole covalently bound at the 2-(beta-pyrrolic) position have been synthesized. The visible absorpt ion maxima (lambda(max)) of the 2-substituted TPVP with an electron wi thdrawing group attached is shifted toward the red region (7-11 nm) co mpared with that of the original TPVP. The iron(II) complexes having a n imidazolyl group at the beta-pyrrolic position were five coordinated species with an intramolecularly bound base under argon and reversibl y formed a stable dioxygen adduct in response to O-2-pressure in tolue ne at 25 degrees C. These molecules act as efficient dioxygen carrying molecules. The kinetics of O-2 binding to the 2-substituted Fe(TPVP) complexes are described.