Core–shell magnetic mesoporous N-doped silica nanoparticles: solid base catalysts for the preparation of some arylpyrimido[4,5-b]quinoline diones under green conditions

Abstract

Preparation of core–shell magnetic mesoporous N-doped silica nanoparticles as a new solid base catalyst was studied. obtained catalyst was used for the preparation of some arylpyrimido[4,5-b]quinoline diones under green conditions.

Loading of g‐C3N4 on Core‐Shell Magnetic Mesoporous Silica Nanospheres as a Solid Base Catalyst for the Green Synthesis of some Chromene Derivatives under Different Conditions

“…The procedure applied for the synthesis of mSiO 2 /g‐C 3 N 4 composite is presented in Scheme 2. After preparation of magnetic mesoporous silica nanoparticles (mSiO 2 ) (according to our previous work [23] ), acidic solution of melamine as a precursor of g‐C 3 N 4 was added to the synthesized mSiO 2 NPs. Therefore, most of the melamine molecules stuck into the channel pores and on the surfaces of mSiO 2 NPs.…”

“…Conforming our prior work, [23] 0.085 g FeCl 2 • 4H 2 O and 0.2 g FeCl 3 • 6H 2 O (the molar ratio of Fe 3 + /Fe 2 + being equal to 1.75) were added into 50 mL of deionized water at 85 °C. Next, ammonia solution (0.6 mL) was added to the mixture and stirred under an inert nitrogen atmosphere at 85 °C for 30 min.…”

“…The preparation of mSiO 2 nanoparticles was done according to our previous work. [23] 0.1 g of the synthesized magnetic NPs and 0.7 g CTAB were added into 160 mL of deionized water and the mixture was sonicated for 10 min in a bath sonicator. Then, the obtained mixture was added to 220 mL of ethanol containing 1.2 mL of the…”

“…Thus, restricting the formation of long layers of g‐C 3 N 4 can cause to break them to the short chains which cater numerous structural defects and high specific surface area on its layers [21,22] . In this regard, mesoporous silica nanoparticles (NPs), due to their properties such as high surface areas (more than 700 m 2 g −1 ), high chemical and thermal stability, appropriate particle size (2 to 10 nm), specific morphology and controllable porosity, are a useful option for catalyst support [23–25] . By using mesoporous silica as a support for the formation of g‐C 3 N 4 layers in their pores, incomplete polymerization occurs, causing an increase in the number of structural defects, edges and basic features.…”

Green Synthesis of Pyrazolo Pyrano Pyrimidine Derivatives Using ZnFe2O4/GA as a New Effective Catalyst in Water Media

“…Despite of their large surface area, usually make it very difficult to separate them from the reaction media, so nowadays, among the NPs, applying the magnetic NPs have been attracted great attention because can be separated easily by means of an external magnetic field. [5][6][7][8][9] Development of heterogeneous catalyst is an important issue in the progress of multicomponent reaction with the high efficiency under mild conditions. Multi component reactions (MCR) are in which more than two starting materials used to form the product.…”