Metallo Salicylidenetriazol Complexes Encapsulated in Zeolite-Y: Synthesis, Physicochemical Properties and Catalytic Studies

Abstract

Chromium(III), zinc(II) and nickel(II) complexes of thio-Schiff base derived from salicylaldehyde and 4-amino-2,4-dihydro-1,2,4-triazole-5-thione have been encapsulated in the nanopores of zeolite-Y by a flexible ligand method. The prepared encapsulated metal complexes have been characterized by surface analysis (XRD and N 2 adsorption/desorption), spectroscopic methods, chemical and thermal analyses. The various techniques of characterization used demonstrated that these complexes were effectively encapsulated in the zeolite supercages without structural modification or loss of crystallinity of the zeolite framework. The encapsulated complexes were screened as heterogeneous catalysts for various oxidation reactions such as phenol, cyclohexene and styrene oxidation, using H 2 O 2 as an oxidant. Under the optimized conditions, these catalysts exhibited high to moderate activity. After a few cycles these catalysts were found to be stable and could be reused after recovering without detectable catalyst leaching or significant loss of activity.

Mn(II) and VO(IV) Schiff base complexes encapsulated in nanocavities of zeolite-Y: catalytic activity toward oxidation of alkenes and reduction of aldehydes

“…In zeolite-Y, the peak intensity is in the order: I 220 > I 311 [21], while in Mn-exchanged and Mn-entrapped complex, the order of peak intensity became I 311 > I 220 (Fig. 1).…”

Encapsulation of a copper(II) tetradentate Schiff base complex in zeolite NaY: an efficient heterogeneous catalyst for the synthesis of benzimidazoles

“…Also, the catalyst showed a narrow BJH pore size distribution curve as shown in Fig. 4c [23]. BET surface area (S BET ), total pore volume (Vp), mean pore diameter derived from the BET plot (D BET ) and the BJH plot (D BJH ), surface area derived from Langmuir plot (S Lang ) and t-plot (S t ), micropore volume (V mic ), the external surface area of crystals derived from a t-plot (S ext ) of the encapsulated complex and also BET surface areas (S BET ), total pore volumes (Vp) of zeolite NaY and Cu(II)/ Y are listed in Table 3.…”

“…4). Abbo et al [23] have previously reported the N 2 adsorptiondesorption isotherm of pure zeolite NaY. According to IUPAC classification, the isotherms of zeolite NaY and the [20].…”

Biosorption of Heavy Metals – New Perspectives

“…Masoud Salavati-Niasari has devoted his work to preparing this type of catalysts for oxidation reactions such as cyclohexene, studying different metals and supports, although recurrently using Y zeolite for the encapsulation of the metal complexes [111][112][113]. In a recent paper, Abbo and Titinchi reported the in-situ synthesis of thio-Schiff base complexes of Cr m , Zn 11 and Ni" in Y zeolite [114]. The authors conducted the oxidation of cyclohexene with H 2 0 2 at 80°C and observed that both Ni and Cr encapsulated complexes present good activity for the reaction, achieving more than 70% conversion, whereas the Zn counterpart was not as active.…”