Zirconium Schiff-Base Complex Modified Mesoporous Silica as an Efficient Catalyst for the Synthesis of Nitrogen Containing Pyrazine Based Heterocycles

SBA-15 Supported Cesium Catalyst for Methyl Methacrylate Synthesis via Condensation of Methyl Propionate with Formaldehyde

“…Figure showed the IR spectra of the SBA-15 and supported catalyst. The spectrum of the pure SBA-15 (Figure a) exhibited three characteristic bands of the silica: Si–O–Si symmetric stretching vibration (804 cm –1 ), Si–O stretching vibration of Si–OH and Si–O groups on the surface (964 cm –1 ), and Si–O–Si asymmetric stretching vibration related to a broad absorption band (1080 cm –1 ). , In Figure b, the peak observed at 1380 cm –1 could be assigned to the stretching vibration of the nitrate. However, a significant decrease in the intensity of the absorption band at 964 cm –1 associated with Si–OH was observed, which implied the consumption of −OH groups due to anchoring of active components onto SBA-15.…”

“…SBA-15, a new type of mesoporous silica material composed of two-dimensional hexagonal arrays of channels, was synthesized by using a triblock copolymer (P123, EO 20 PO 70 EO 20 ) as structure-directing agent under strongly acidic conditions. As a result of its large specific surface area, uniform pore size distribution, and better thermal and hydrothermal stability, SBA-15 has received much attention as the most promising catalytic material. − …”

Comparative study for synthesis of novel Mn (II), Co (II), Ni (II), Cu (II), Zn (II) and Zr (IV)complexes under conventional methods and microwave irradiation and evaluation of their antimicrobial and Anticancer activity.

“…Thus, the tetrahedral geometry [22,31] has been suggested for Cu (II) complex, the electronic spectra of Zn (II) complex shows bands at 34602, 30488, 24875 cm -1 are assigned to π -π*, n-π*, ligand to metal transfer (LMCT) transitions respectively with diamagnetic properties suggesting an octahedral geometry around Zn (II) ion [2,22]. for Zr (IV) complex shows three bands at 35714, 31056, 25000 cm -1 are assigned to π -π*, n-π*, ligand to metal transfer (LMCT) transitions respectively with diamagnetic properties suggesting a distorted trigonal bipyramidal geometry around Zr (IV) ion [32][33][34].…”

Porous Catalytic Systems in the Synthesis of Bioactive Heterocycles and Related Compounds

“…Zirconium Schiff-base complex modified SBA-15 (Zr-SBA-15) was used as catalyst in the synthesis of quinoxalinebased heterocycles such as pyridopyrazine, pyrazine, and quinoxaline derivatives [156]. 2,3-Disubstituted quinoxalines among others were prepared, in water media, in good-to-excellent yields.…”