Expedient, accurate methods for the determination of the degree of substitution of cellulose carboxylic esters: Application of UV–vis spectroscopy (dye solvatochromism) and FTIR
In the present study silver nanoparticles (AgNPs) have been synthesized through the cell-free extracts of the rooftop dwelling cyanobacterium Scytonema geitleri HKAR-12. UV-VIS spectroscopy, FTIR, X-ray diffraction, SEM and TEM were used for the determination of morphological, structural and optical properties of synthesized AgNPs. Extracts of Scytonema geitleri HKAR-12 have the ability to reduce AgNO3 to Ag0. Sharp peak at 422 nm indicated the rapid synthesis of AgNPs. FTIR results showed the presence of different groups responsible for the reduction of AgNO3 to AgNPs. XRD pattern confirmed the crystalline nature of AgNPs. SEM showed the bead shape structure of AgNPs. TEM confirmed the actual size of AgNPs to be ranging between 9-17 nm. AgNPs showed antibacterial activity against Pseudomonas aeruginosa, Escherichia coli strain1 and E. coli strain 2 and 11 μg/mL of AgNPs effectively inhibited the growth of MCF-7 cells. Hence, Scytonema geitleri HKAR-12, isolated from the rooftop could serve as a desirable biological candidate for convenient and cheap production of AgNPs having antimicrobial and anti-cancerous properties.
Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by 1H-NMR, 13C-NMR, IR, UV-Vis spectroscopy, mass spectrometry and elemental analysis. In addition, the X-ray single crystal structure of a representative azo dye was presented. For explicit determination of the influence of a substituent on radiation absorption in UV-Vis range, time-dependent density functional theory calculations were performed.
Non-destructive and direct determination of the degree of substitution of carboxymethyl cellulose by HR-MAS 13C NMR spectroscopy