Reactions of Nitro and Halonitro Derivatives of Aluminum(III) and Copper(II) Phthalocyanines with Concentrated Sulfuric Acid

摘要

Transformations of the complexes CuPc(4-NO_2)_4, CuPc(4-Br)_4(5-NO_2)_4, (OH)AlRs(4-NO_2)_4, and (OH)AlPc(4-Cl)_4(5-NO_2)_4 in concentrated sulfuric acid were studied by spectrophotometry. One protonasted form of CuPc(4-Br)_4(5-NO_2)_4 and (OH)AlPc(4-NO_2)_4 and two protonated forms of CuPc(4-NO_2)_4 and (OH)AlPc(4-Cl)_4(5-NO_2)_4 were detected experimentally and also by ZINDO1 calculations. Step protonation constants of CuPc(4-NO_2)_4 and (OH)AlPc(4-Cl)_4(5-NO_2)_4 were determined byu quantum-chemical cal-culations and acid-base titration; these complexes can be regatrded as weak bases with respect to H_2SO_4. The kinetics of dissociation of the complexes at the M-N bonds were studied. The rate of dissociation of the Cu(II) complexes and (OH)AlPc(4-NO_2)_4 is proportional to [MPc(R)_n] and [H_3O~+]~2. The rate of dissociation of (OH)AlPc(4-Cl)_4(5-NO_2)_4 showed a weak extremal dependence on the composition of the medium, which was explained by change of its structure in 17.0 M H_2SO_4. The electronic effect of substituents on the reaction center was considered with account taken of a complex mechanism of activation and fine details of the molecular structure of macrocyclic complexes.