TY - JOUR

T1 - Basicity of para-Substituted Tetraphenylporphyrins Studied by Two-Phase Spectropotentiometric Titration

AU - Starikova, A.A.

AU - Valiotti, A.B.

AU - Pendin, A.A.

PY - 2014

Y1 - 2014

N2 - The basicity constants of a series of para-substituted tetraphenylporphyrins have been determined by two-phase spectrophotometric titration with pH monitoring in the chloroform–aqueous electrolyte solution system; the pH ranges of prevailing of the dication and the neutral forms of the porphyrins have been estimated. With introducing the donor substituents at the para-position of phenyl fragments of porphyrins, the compound basicity increases. Ionization constant of the pyrrole nitrogen atoms depends on the donor-acceptor properties of the substituents according to the Hammett equation. Basing on the derived dependence, theoretical basicity constants of the para-substituted porphyrins bearing strongly donor groups have been predicted.

AB - The basicity constants of a series of para-substituted tetraphenylporphyrins have been determined by two-phase spectrophotometric titration with pH monitoring in the chloroform–aqueous electrolyte solution system; the pH ranges of prevailing of the dication and the neutral forms of the porphyrins have been estimated. With introducing the donor substituents at the para-position of phenyl fragments of porphyrins, the compound basicity increases. Ionization constant of the pyrrole nitrogen atoms depends on the donor-acceptor properties of the substituents according to the Hammett equation. Basing on the derived dependence, theoretical basicity constants of the para-substituted porphyrins bearing strongly donor groups have been predicted.

KW - tetraphenylporphyrins

KW - spectrophotometric titration

KW - Ionization constant

KW - the Hammett equation

U2 - 10.1134/S1070363214010150

DO - 10.1134/S1070363214010150

M3 - Article

VL - 84

SP - 98

EP - 102

JO - Russian Journal of General Chemistry

JF - Russian Journal of General Chemistry

SN - 1070-3632

IS - 1

ER -