Application of GO/COF as a novel, efficient and recoverable catalyst in the Knoevenagel reaction

Abstract

Hybrid composite based on graphene oxide (GO) and covalent organic framework (COF) [GO/COF] was developed via a simple solvothermal method, at which GO was applied as a platform to load COF based on melamine and terephthaldehyde. The synthesized hybrid nanocomposite was characterized by FT‐IR, XRD, EDX and SEM techniques. Morphological analyses carried out by SEM confirm the successful growth of COF over GO. Then, the resultant composite was employed as an amazing and cost‐effective catalyst in the condensation of several aldehydes with malononitrile and produced the corresponding coupling products in high yields (up to 84%) at room temperature under solvent‐free conditions with an amount of catalyst, 15 mg in a very short reaction time of 10 min. The catalyst could be reused without a noteworthy drop in catalytic activity at least eight times. The use of GO/COF catalyst outcomes under mild reaction conditions in very short reaction time, exceptional catalytic activity, high recyclability and an easy work‐up process for the Knoevenagel condensation.

Phenolic Hydroxyl‐Functionalized Covalent–Organic Frameworks for Formal [3+2] Reaction

“…Fourier-transform infrared (FTIR) and solid-state 13 C nuclear magnetic resonance (SS 13 C NMR) spectroscopy were used to characterize the synthesized COFs (Figure S1, Supporting Information, and Figure 1). The characteristic stretching peaks at 1611 cm −1 evidenced the formation of C═N at the joint of the COFs.…”

“…The characteristic stretching peaks at 1611 cm −1 evidenced the formation of C═N at the joint of the COFs. In the SS 13 CNMR spectrum of [OH] 0% -PyTTA-COF, the carbon signal of the C═N and CH 3 groups appeared at chemical shifts of 158.4 and 16.4 ppm, respectively, while the peaks of the pyrene and benzene rings appeared at 115.5-152.8 ppm. For [OH] 50% -PyTTA-COF, the peaks of C═N and CH 3 appeared at 160.2 and 15.9 ppm, respectively, while the peaks of the pyrene and benzene rings appeared at 115.4-153.1 ppm.…”

“…[1] The progress of synthetic chemistry has resulted in the construction of COFs with different structures for a variety of applications, including ion conduction, [2] catalysts, [3] gas storage and separation, [4] sensors, [5] energy storage and conversion. [6] In the past decades, COFs with different functionalities have been used as heterogeneous catalysts for many organic reactions, such as Suzuki-Miyaura coupling reaction, [7] Henry reaction, [8] Michael addition reaction, [9] Diels-Alder cycloaddition reaction, [10] epoxidation of alkenes, [11] addition of epoxides to CO 2 , [12] Knoevenagel reaction, [13] and a variety of tandem reactions. [14] Nitrogen-containing heterocycles are usually DOI: 10.1002/macp.202100462 important intermediates of pharmaceuticals and agrochemicals because of their various biological functions and properties.…”

Covalent-Organic-Framework-Based Composite Materials

“…The rGO/COF composite was also employed as an efficient catalyst in the condensation of some aldehydes with malononitrile. 78 The catalytic activity of the composite could be well retained after 8 cycles, showing decent recyclability. The graphene/COF composites discussed above generally show enhanced performance in batteries and capacitors, which greatly expand the scope of COF-based materials for energy applications.…”

In situ synthesis of a GO/COFs composite with enhanced adsorption performance for organic pollutants in water

“…Therefore, metal oxides, COFs, MOFs and various nanoparticles can be introduced to overcome this problem and make it more widely used. 21,23–26…”