B. Sankara Reddy

SYNTHESIS OF 2-ARYLOXY-6-METHYL-4-TRICHLOROMETHYL-4H-1,3,2-BENZODIOXAPHOSPHORIN 2-OXIDES/SULFIDES

Abstract Synthesis of 2-aryloxy-6-methyl-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxides and corresponding 2-sulfides and their IR, 1H, 13C and 13P NMR spectral analyses were reported. Long-range 3J H–P, 2J PDC and 3 J POCC couplings were determined. An X-ray diffraction analysis of a crystal of 2(2′,6′dimethylphenoxy)-6-methyl-4-trichloromethyl-4H-1,3,2-benzodioxaphosphorin 2-oxide suggested distorted-boat conformation for the dioxaphosphorin ring with P[dbnd]O directed away from the ring. Electron impact mass spectra exhibited M+, (M[sbnd]Cl) +, (M[sbnd]Cl)[sbnd]-HCl)+ and (M[sbnd]CCl3)+ as major ions with the dioxaphosphorin ring intact supporting the proposed structures of these esters. Toxicity of some of the compounds against the insect, P. americana, was evaluated and their LD50 values were reported.

Doping effect of Ag+, Mn2+ ions on Structural and Optical Properties of ZnO nanoparticles

Pure ZnO and co-doped (Mn, Ag) ZnO nanoparticles have been successfully prepared by chemical co-precipitation method without using a capping agent. X-ray diffraction (XRD) studies confirms the presence of wurtzite (hexagonal) crystal structure similar to undoped ZnO, suggesting that doped Mn, Ag ions are substituted to the regular Zn sites. The morphology of the samples were studied by scanning electron microscopy (SEM). The chemical composition of pure and co-doped ZnO nanoparticles were characterized by energy dispersive X-ray analysis spectroscopy (EDAX). Optical absorption properties were determined by UV-vis Diffuse Reflectance Spectrophotometer. The incorporation of Ag+, Mn2+ in the place of Zn2+ provoked to decrease the size of nanocrystals as compared to pure ZnO. Optical absorption measurements indicates blue shift in the absorption band edge upon Ag, Mn ions doped ZnO nanoparticles.

Synthesis and structural properties of pure and co-doped (Cu, Ag) ZnO nanoparticles

Pure ZnO and co-doped (Cu, Ag) ZnO nanoparticles (Zn0.90Cu0.05Ag0.05O) are synthesized by chemical co-precipitation method in the presence of capping agent polyethylene glycol 600 (PEG 600) and annealed at 500 °C for 1h. The XRD measurements indicate that the samples show hexagonal structure without any change and the nanocrystalline size decreased from 12 to 5 nm. SEM images are of hexagonal structure of the ZnO and co-doped ZnO samples, and EDAX spectra reveals that the successful doping concentration of Cu and Ag.

Preparation and structural properties of pure and codoped (Mg, Ag) ZnO nanoparticles

Pure and co-doped (Mg, Ag) ZnO nanoparticles (Zn0.90Mg0.05Ag0.05O) are synthesized by chemical co-precipitation method in the presence of capping agent Polyethylene glycol 600 (PEG 600) and annealed at 500°C in air ambient for 1h. The XRD measurements reveals that the pure and co-doped ZnO samples have hexagonal structure without any change and the size of ZnO nanoparicles were decreased from 17 nm to 13 nm. FESEM images indicates that they are flake like structures of the ZnO and co-doped ZnO samples and ED AX spectra reveals that the successful doping concentration of Mg and Ag. From the TEM results, the size of the ZnO nanoparticles which are in good agreement with the XRD results.

Structural and optical properties of Ag and Co doped ZnO nanoparticles

Undoped and Ag, Co doped ZnO nanoparticles were Synthesized by Chemical Co-Precipitation method without use of capping agent. The X-ray diffraction results indicated that the synthesized codoped ZnO powders had the pure Hexagonal structure with out any significant change in the structure affected by Ag and Co. Substitution dopants Ag and Co elements are present in the ZnO host material and it conformed with the EDS spectra. Light blue emission was observed by PL spectra.

Preparation and Characterization of Ag and Co Doped ZnO Nano Particles

Pure ZnO and Ag, Co doped ZnO nano particles [Zn1-xAgxCoyO, where x = 0.00 and 0.05, y = 0.05] were synthesized by chemical co precipitation method without use of surfactant. All the prepared samples calcinated in 1 hour at 500oC, after that the morphology of the samples were evaluated by Scanning Electron Microscope (SEM). The X- ray diffraction (XRD) results indicated that the synthesized co-doped ZnO nano crystals had the pure hexagonal structure without any significant change in the structure affected by Ag and Co substitution. Dopant elements Ag and Co are present in the ZnO host material and conformed by Energy Dispersive Analysis of X-ray Spectra (EDAX). The incorporation of Ag+ in the place of Zn2+ has made a considerable decrease in the size of nano crystals as compared to pure ZnO nano particles (It is to be noted that Co should be kept constant at 5 mol %). Blue emission was observed by Photo Luminescence (PL) Spectra.