1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO2-nano-NiFe2O4 (BPBTCSF): As a novel and effectual mesoporous bi-functional magnetic catalyst for the synthesis pyrido[2,3-d:6,5-d']dipyrimidines

• Bi-functional magnetic catalyst with SiO 2 @NiFe 2 O 4 core. • Heterogeneous catalyst system with acidic and basic sites. • Rapid synthesis of pyrido[2,3- d :6,5- d' ]dipyrimidines. • Multicomponent reaction in water-green solvent at 25 ° C. • Represents advantages: appropriate reproducibility of the catalyst (6 runs), high TOF and TON numbers, easy separation by filtration in the presence of an external magnet, high efficiency (90% to 98%), and compliance with the principles of green chemistry. Here in, we report the synthesis of 1,4-Bis(pyridin-1-ium)benzene trifluoroacetate coordinated to chloropropyl functionalized SiO 2 -nano-NiFe 2 O 4 (BPBTCSF). Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), elemental mapping analysis, Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), vibrating-sample magnetometry (VSM) and X-ray diffraction (XRD) techniques characterized the framework of this catalyst. The catalytic activity of this nano-composite was then examined in the one-pot four-component reaction of 2-thiobarbituric acid, NH 4 OAc, and aldehyde for synthesis of pyrido[2,3- d :6,5- d' ]dipyrimidines under optimal conditions (5 mg of BPBTCSF, H 2 O, 25 ° C). BPBTCSF exhibits benefits as a heterogeneous catalyst, such as exciting performance in the production of derivatives (2 to 5 min, 90% to 98%), six times reproducibility with a slight decrease in catalytic activity, the simultaneous presence of acidic and basic sites (Hydrogen attached to the electronegative nitrogen atom and CF 3 COOˉ, respectively), convenient purification and separation from the reaction mixture.