Unusual catalytic activity after simultaneous immobilization of two metalloporphyrins on hydrozincite/nanocrystalline anatase

The Research on Porphyrins and Analogues in Brazil: A Small Review Covering Catalytic and other Applications since the Beginning at Universidade de São Paulo in Ribeirão Preto until the Joint Venture between Brazilian Researchers and Colleagues from Universidade de Aveiro, Portugal

“…Thus, the solid was used for the immobilization of one cationic FeP ([Fe(T 4 MPyP)], Figure 4, R = 17), one anionic MnP ([Mn(TDFSPP)], Figure 4, R = 20) and both ionic metalloporphyrins. 123 In spite of the low MP loading in all the solids prepared (about 10 -6 mol of MP per 1 g of solid support), all the three solids (named FeP-C, MnP-C and FeP-MnP-C) were more efficient than the non-immobilized metalloporphyrins when they were used as catalysts in the oxidation of cyclohexane under dark conditions. These results were attributed to the poor solubility of both MPs in the dichloromethane/ acetonitrile mixture (1:1, v/v) used as solvent in the reaction ( Table 2).…”

“…These types of materials occur in nature (e.g., natural clays) 64,[103][104][105][106][107][108][109][110][111]113,167,168,176 or can be prepared, yielding layered double hydroxides (LDH) 60,[115][116][117][118][119][120][125][126][127][128][129]177 or just layered hydroxide salts (LHS). [121][122][123] These compounds are robust, relatively inexpensive, easy to produce and use as supports, mainly for charged catalytic species.…”

“…The combination of the catalytic properties of MPs immobilized on layered solids and titanium-based supports generates great interest in the context of using the resulting material in photocatalysis. 186,187 In spite of the controversy in the literature about the preparation of layered compounds like layered double hydroxide containing Ti IV , [188][189][190] recently Mantovani et al 123 described the preparation of new solids based on layered solids containing titanium oxide. The authors applied the usual method to produce LDH-the urea hydrolysis method- 191 and studied the use as support for the immobilization of MPs in order to investigate the possible application of the resulting solids in catalysis and catalytic oxidation reactions assisted by light.…”

Recent Advances in Catalyzed Sequential Reactions and the Potential Use of Tetrapyrrolic Macrocycles as Catalysts

“…In this context, many efforts were made by researchers to propose heterogeneous processes to overcome these problems. Heterogeneous catalytic systems facilitate catalyst recovery via simple processes, such as filtration [ 6 ], decantation [ 8 ], and magnetic recovery [ 9 ] (if the solid is a magnetic particle), among others.…”

“…There are many reports of the preparation of solid catalysts via their immobilization onto inert and usually inorganic matrices, such as layered double hydroxides [ 10 ], mesoporous silica [ 11 , 12 ], titanium oxides [ 8 ], zeolites [ 13 ], magnetic particles [ 14 ], and many more [ 15 , 16 , 17 , 18 ], in order to recover the catalyst for reuse. In addition, catalyst immobilization on inert matrices can produce unusual activities and synergism between the interacting species [ 19 ].…”