Tetrapyrrolic Macrocycles with Magnesium, Alluminum, and Zinc in Hydrogen Peroxide Decomposition - Progress in Organic and Physical Chemistry: Structures and Mechanisms - page 126

different from the achieved for the samples with forced immobilization. As a result,
coordination of Chl with the OH-groups of silica in this case has little effect on the
photochemical process. It follows that in these systems use of the equilibrium adsorp-
tion is more effective.
Trend to photodecompose of H 2 O 2 , which is typical for natural Chl, was similar to
one observed for synthetic analogue AlClPc. Table 1 show that AlClPc exhibits photo-
catalytic activity growing with decrease of phthalocyanine adsorption degree on silica
(Figures 3 and 4). Adsorption isotherm for AlClPc is shown in Figure 2. Characteristic
plateau corresponding to achievement of the tetrapyrrol monomolecular layer on the
carrier surface is observed in the concentration range of 0.1-0.28 mmol/l with an aver-
age degree of adsorption a § 0.95 —mol/ g.
FIGURE 2 Isotherm of adsorption of alluminum phthalocyanine on silica, a - the value of
adsorption, c - concentration of alluminum phthalocyanine in DMF.
The dark activity of AlClPc decreases to ~1.5 times in the case of monolayer ad-
sorption and by ~70% in other cases (Table 1). In the absence of irradiation AlClPc ac-
tivity in the hydrogen peroxide decomposition was the greatest for monolayer coating