Pd/Halloysite as a Novel, Efficient and Reusable Heterogeneous Nanocatalyst for the Synthesis of p‐Phenylenevinylene Oligomers

Abstract

The potential applications of poly(p‐phenylene vinylene) derivatives and its oligomers in organic electronics have attracted great interest in recent years. In this study, a novel palladium supported on halloysite heterogeneous catalyst (Pd/HNTs) was prepared, characterized and its catalytic activity for obtaining p‐phenylenevinylene oligomers was investigated in the Heck coupling of styrene and 2,5‐diiodo‐1,4‐dimethoxybenzene using conventional and environmentally benign solvents. Thus, in the presence of 0.75 mol% catalyst, the product was obtained in 76% yield using ethanol as solvent. To evaluate the versatility of the Pd/HNTs catalyst, the synthesis of a series of p‐phenylenevinylene oligomers and divinylbenzene derivatives was performed obtaining yields between 58 and 93%. In addition, the catalyst could be recovered and reused for four reaction cycles without significant loss of its catalytic activity. Finally, the photophysical characterization of the synthesized molecules was performed.

Catalytic degradation of real-textile azo-dyes in aqueous solutions by using Cu–Co/halloysite

“…X-ray powder diffraction profiles of the synthesized solids and Ha (fresh). a support[37]. A small amount of quartz (SiO 2 impurity) was also detected, in agreement with the chemical analysis of Ha.…”

“…Halloysite (Ha) is an interesting 1:1 clay mineral (1:1 aluminosilicate) with a nanotubular structure. This natural material has a tetrahedral sheet of silicates (SiO 4 units) covalently bonded to an octahedral sheet of hydrated alumina (AlO 6 ) (both Si 4+ and Al 3+ species coordinated with oxygen and/or hydroxyl groups) to form complete 1:1 layers [37]. In this clay mineral, layers are rolled to form nanometric tubular structures.…”

Study of the effect of the ligand structure on the catalytic activity of Pd@ ligand decorated halloysite: Combination of experimental and computational studies

“…This feature significantly increased the use of Hal in the catalysis. To date, vast heterogeneous catalysts with promising performances have been developed through immobilization of catalytic species on the surface of modified Hal …”

“…To date, vast heterogeneous catalysts with promising performances have been developed through immobilization of catalytic species on the surface of modified Hal. [15][16][17] In continuation of our research on the development of environmentally-benign catalytic protocols for chemical transformations, including hydrogenation reaction, recently we have disclosed the outstanding performance of Hal as a catalyst support in its functionalized or hybrid forms. [18][19][20][21] To shed light to the chemistry of Hal, we exploited both experimental and computational chemistry and attempted to find the relationship between the structural features and catalytic activities of Hal-based catalysts.…”

Oenothera Biennis Extract as Reducing Agent for the Synthesis of Pd NPs Supported on Halloysite Functionalized With Schiff Base: an Efficient Catalyst for Cu- and Ligand-free Sonogashira Reaction in Aqueous Media 

“…Moreover, metal complexes of Schiff bases display a diverse range of biological activities and also catalytic activity in different transformations. [14][15][16][17] Among palladium-catalyzed cross-coupling reactions, the Sonogashira cross-coupling which allows the construction of C (sp 2 )-C (sp) bonds by coupling aryl or vinyl halides with terminal alkynes is one of the prominent and practical synthetic methods in organic synthesis. 18 The resultant aryl alkynes and conjugated enynes are extensively utilized in the fabrication of polymers, pharmaceutical compounds, natural products, substituted alkynes, as well as optical materials.…”