Ultrasound‐Mediated Synthesis of Novel α‐Aminophosphonates Using Graphene Nanosheets‐Silver Nanoparticles (GNS‐AgNPs) as a Recyclable Heterogeneous Catalyst

Abstract

A series of novel α-aminophosphonate derivatives were synthesized via simple and an efficient method from the threecomponent condensation reaction of 5-aminoindan or 3,4-(methylenedioxy)aniline, aromatic aldehydes and diethyl phosphite by employing graphene nanosheets-silver nanoparticles (GNS-AgNPs) as catalyst under ultrasonication and solvent-free condition. GNS-AgNPs was prepared in situ by simultaneous reduction of graphene oxide (GO) and silver nitrate (AgNO 3 ) using sodium borohydride (NaBH 4 ) as a reducing agent. The surface characterization of GNS-AgNPs was done using X-ray diffraction (XRD), Fourier transform infrared (FTIR), UV-Vis spectroscopy (UV-Vis), Thermogravimetric analysis (TGA), Raman spectroscopy and Field emission scanning electron microscopy (FE-SEM). The GNS-AgNPs are recyclable up to fifth run with minimal loss of its activity. Convenient operational simplicity, mild conditions, excellent yields of products, consistent performance and the reusability of catalyst makes this protocol feasible and attractive.

Rapid synthesis and characterization of silver-loaded graphene oxide nanomaterials and their antibacterial applications

“…GO had a large surface area and contained a large amount of oxygen-containing functional groups. These groups on the GO sheet provided the chemically active centres for the deposition of AgNPs, while the AgNPs were well separated from each other [ 7 ]. In addition, it was noteworthy that the C : O ratio in the T6 sample was less than that of the T9 sample, but the Ag content was higher than T9, mainly owing to the fact that the oxygen-containing groups on the GO sheet were the main active points in the reaction, which could attract Ag + onto the GO surface [ 22 ].…”

“…The development and application of new nanomaterials whose characteristics can combine MNPs with graphene or its derivatives have aroused much interest. To our knowledge, there are several ways to incorporate MNPs into graphene and its derivatives, such as chemical methods, chemical vapour deposition and wave radiation [ 7 , 11 ]. Among them, ultrasonic radiation from Ag + /GO to Ag/GO is the most suitable and effective method.…”

“…However, owing to strong plane-to-plane interactions, GO tends to accumulate layer by layer in aqueous solutions, which potentially limits its application. It is worth noting that if nanoparticles are coated on the surface of the GO layer, these nanoparticles (such as Ag, Au and Pt) will separate adjacent flakes and prevent their aggregation [7][8][9]. Meanwhile, the abundant functional groups on the surface of GO can act as nucleation centres or anchor positioning points, which limits their growth and improves the stability and dispersion of MNPs just like AgNPs on GO nanosheets.…”

Greener organic synthetic methods: Sonochemistry and heterogeneous catalysis promoted multicomponent reactions

“…A strategy well aligned with the green chemistry principles and which has been gaining prominence in recent years in the field of heterogeneous catalysis is the immobilization of nanoparticles (NPs) on solid supports, such as porous silica [85] , [86] , [87] , [88] , [89] , zeolites [84] , [90] , [91] , [92] , [93] , polymers [94] , [95] , [96] and carbon-based supports, including carbon nanotubes (CNTs) [97] , [98] , [99] , [100] , graphene [101] , [102] , [103] , graphene oxide (GO) [104] , [105] and graphene nanosheets (GNSs) [103] , [106] . A notable peculiarity of many of these supports – as is the case with graphene - is the property of having the surface easily modifiable, which is only possible due to the presence of large points of nucleation or stabilization [103] . Other characteristics of these materials that make them remarkable interesting from the point of view of catalysis are porosity, low interaction with supported materials, and good mechanical resistance [105] , [106] , [107] , [108] , [109] .…”

Investigation of thermal and mechanical properties of styrene–butadiene rubber nanocomposites filled with SiO2–polystyrene core–shell nanoparticles

“…Nowadays, nanoscience and technology gaining the fast momentum in the field of polymer science and technology due to drastic improvement in properties of materials as compared to bulk. 1–4 Due to addition of nano size materials such as SiO 2 , 5 TiO 2 , 6 CaCO 3 , 7 CaSO 4 , 8 Mg(OH) 2 , 9 MMT, 10,11 Cu, 12 CNTs, 13 and ZnO, 14 properties of polymer nanocomposites (optical, electrical, mechanical, thermal, and physical properties) were found to be improved drastically even at lower amount of loading. 15–17 This enhancement is due to increase in surface-to-volume ratio with improved polymer–filler interaction.…”